UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION CIRCULAR No. 278 September, 1924 Olive Pickling in Mediterranean Countries BY W. V. CEUESS Although olives are grown in the Mediterranean countries prin- cipally for oil, a considerable portion of the crop is used for the preparation of various kinds of pickled and cured olives. Some of the olives are prepared by processes similar to that in use for ripe olives in California; others by processes that are distinctly different. The various processes may be classified as follows : 1. The Spanish green olive process. 2. The French process. 3. The brine process. 4. The dry salt process. 5. The water process. 6. The Italian dried olive process. In the Spanish and French processes lye is used to destroy all or most of the bitterness ; in the other processes lye is not used. Brine or salt cured olives are preferred by southern European consumers, while the Spanish lye-treated, fermented olives are most in demand for export. However, important quantities of brine or salt cured olives are imported by the United States and consumed by people of southern European origin. While the Californian olive industry depends at present upon the black olive, it is probable that profitable markets could be developed for limited quantities of other types. It is for this reason that the European methods are described in this publication. The material presented was obtained during a recent visit to the olive districts of southern Europe. Thanks are due to the California Ripe Olive Association for financial assistance which made the trip possible. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION CULTURE OF OLIVES USED FOR PICKLING European cultural practices in the growing of olives for pickling differ in several important respects from those in use in California. A brief resume of observations upon olive culture in olive pickling districts of Spain and France should be of interest to California growers. Little first hand information on the growing of olives for pickling in Italy was obtained, most of the observations in Italy being made upon groves in which the olives are grown for oil making. Spain.- — The industry is confined to a small area surrounding Seville in southern Spain. Very few green olives are prepared at a distance exceeding twenty miles from this city. The reason given for this situation is that only the olives of the Seville district possess the proper quality for green pickling. The olives are grown for the most part on large estates known as "fincas, " in this respect differing from conditions in northern Spain and southern France, where small orchards prevail. Extent of the Green Olive Industry. — W. T. Gracey, former American consul at Seville, placed the total area of olive plantings in Spain in 1915 at about 3,600,000 acres. According to the same authority, the crop of Spain in a recent year was approximately 1,953,700 tons of olives for all purposes, and of these the province of Seville produced 379,300 tons. Only 21,000 tons, or about 1.7% of all the olives of Spain or 5.6% of those of Seville were used for green pickles. The production in 1922 was, according to the American Consul W. C. Burdette of Seville, 3,280,000 gallons of green pickles (20,500 fanegas = 9,900 tons) ; in 1921, 5,600,00 gallons and in 1920, 9,600,000 gallons (29,000 tons). Evidently production varies greatly from year to year, and apparently Spanish olive growers are unable to overcome the tendency for olives to bear irregularly. It is customary to assume 25 per cent of the total production to be unsuitable for export. According to Burdette, in 1922 the exports totaled 4,604,113 gallons (includes hold-over from 1921) and brought $4,308,807, f .o.b. Seville ; a price of approximately $0,936 per gallon. This represents an unusually high price — probably at least twice the average price of previous years. Propagation of Trees. — According to Mr. Gracey, former American consul, in the Seville district the average number of trees to an acre varies from 36 to 40. CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 3 Several systems of propagating trees are in common use. Of these the most important are the following : a. Estacas. — A piece of an olive branch 17 to 20 inches long and about 2% to 2% inches thick is planted vertically in the nursery in a hole about 18 inches deep. Three shoots only are allowed to grow for four years in the nursery. The estaca is then transplanted in the late summer or early fall. The young trees are planted in a hole about three feet deep in the bottom of which is placed a layer of manure covered with earth. Clay is mounded up around the tree to a height of two feet or more above the ground level giving the appearance of an ant hill. This mound retains the moisture and prevents formation of shoots near the base of the ' ' estaca. ' ' A hole is left half way up the mound and through this the tree is watered at the time of planting and several times during the fall, if rains are late. b. Garrotes. — These are pieces of pruning wood of about the size mentioned above for estacas, planted in the nursery two in a place, with the two pieces leaning toward each other forming a triangle with the apex even with the ground. Only one shoot from each "garrote" is allowed to grow, giving two trees from each hole for transplanting. Trees from estacas bear in four to five years; those from garrotes in eight to ten. c. Zuecas. — These are protuberances ("ovoli" of the Italians) cut from the tree and planted either direct in the orchard or in the nursery to be transplanted later. d. Raices. — These represent root cuttings used for propagation. e. Retofws. — These are suckers cut from the tree beneath the ground. /. Grafting. — Wild trees or undesirable varieties of cultivated trees are often grafted in place in the orchard. Seeds of wild olives are also planted in the nursery and the young seedlings from the nursery planted in the orchard to be grafted later. According to one of the large packers, who is familiar with cultural methods, the better olive growers prefer trees of Sevillano and other pickling varieties grafted on wild olive roots to trees grown from estacas or other forms of cuttings. March is considered the best month for grafting in the Seville district. Cleft grafts with four to five buds or bark grafts are used. Owing to the large demand for Sevillano and Manzanillo olives during the past two or three years, a considerable number of oil olive trees are being grafted with pickling varieties. 4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Irrigation. — In most seasons the rainfall is sufficient to produce fruit of good pickling quality and irrigation of the orchards is not usually practiced. Inadequate rainfall and very hot summers occa- sionally cause the fruit to be smaller than is desired for pickling. This was the case in 1923. Cultivation. — Soil moisture is conserved by three or more plowings or cultivations to prevent excessive growth of weeds and grass. In a few orchards wheat or some other field crop is grown between the rows, but this practice results in small fruit and poorly nourished trees. The usual plow is home made. It has one handle, a wooden beam and steel share. See fig. 1. Hi Fig. 1. — Typical plow and ox team. Near Seville. Pruning. — Pruning has a very important place in olive culture in the Seville district. Two systems are used, an annual and a biennial. In the annual system the trees are pruned lightly every year ; in the biennial, somewhat more severely once every two years. In each system the object is to promote regular bearing by causing the tree to exhibit a suitable supply of two-year wood every season. In both systems the center of the tree is made open and the crowding of branches and twigs prevented by thinning out surplus wood. The trees and particularly the centers are much more open than in Cali- fornia. The objects of pruning as practiced in the orchards: of Seville are given by Guillen-Gareia* as follows : * 101 Olivo, by D. Guillermo J. de Guillen-Garcia, 1917. Libreria de Francisco Ping, Plaza Nueva 5, y Capellanes 2, Barcelona, Spain. Publishers. Circular 278] olive pickling in mediterranean COUNTRIES 5 "1. To obtain new growth for the crop of two years hence. 2. To admit sunlight to aid in the setting of the fruit. 3. To eliminate upright branches, which do not bear fruit. 4. To remove dead and non-bearing wood. 5. To adjust the size of the tree to the water supply and the fer- tility of the soil. 6. To avoid excess of fruiting wood, which excess would give small fruit. 7. To avoid biennial bearing; leaving too little old wood stimu- lates excessive new growth and biennial bearing. 8. To avoid high trees, which are costly to harvest and which bear little fruit. 9. To be so conducted as to avoid cutting off main branches or trunk. ' ' Fig. 2. — Sevillano olive tree before and after pruning. Near Seville. Fig. 2 illustrates the two-year pruning method. Ringing. — Ringing is sometimes employed to obtain larger fruit, earlier ripening and better setting. A strip one-fourth to one inch wide is removed from the bark of the large branches when the tree has begun to blossom but before the flowers have completely developed. Girdling or ringing in this manner retards flow of sap downward and forces it into the fruit with results noted above. Fertilization. — Manure and commercial fertilizers are used in many orchards. The manure and fertilizer are buried in a circular ditch dug around each tree. Annual applications are considered better than biennial or triennial, because they induce more regular bearing. According to W. T. Gracey,* former American consul at Seville, 30 to * Gracey, W. T. Olive Growing in Spain. Special Consular Keport No. 79, From Superintendent of Documents, Washington, D. C. 5 cents. 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 40 pounds of barnyard manure and 3% pounds of superphosphate are applied to each tree. Sodium nitrate or ammonium sulfate 1% to 2 pounds, iy 2 to 2 pounds of potassium chloride, and 3 to 4 pounds of gypsum are also desirable. Proper fertilization promotes the setting of the fruit and increases the size ; but if too abundant, overstimulates leaf production and decreases fruiting. Spanish growers to whom the writer talked believed that irregular production in California may be due principally to improper pruning and lack of fertilizers. Superphosphate is considered the most import- ant ingredient of chemical fertilizers in causing fruit to set properly. Insect Pests. — The most important insect pest is the olive fly, Dacus oleae (in Spanish "la mosca del olivo, " in French "la mouche de 1 'olive")- The fly is much more destructive in olive districts of northeastern Spain than in Seville, although even here it does great damage in some seasons. The fly is a small dipterous insect about 5 millimeters in length (about one-fifth of an inch). According to a prominent olive packer of Seville, the first generation of the fly in the Seville district emerges from the soil in June or July. The female deposits its eggs in the flesh of the olive through the skin, usually one egg to each olive. One female may deposit 100 or more eggs. On the green olive a small black spot marks the spot where the ovipositor of the fly has been inserted. According to Minangoin,* the egg hatches in from 2 to 6 days, according to the temperature. The larva develops rapidly and reaches the pupal stage after 12 to 15 days. During this period it is very active in forming galleries, particularly around the pit, and in eating its way through much of the pulp. The olive becomes soft and rancid and wholly unfit for pickling. It is usually unfit also for good oil, yielding a rancid oil of poor flavor. The larva may pupate immediately beneath the skin of the olive or may emerge from the olive and pupate at some other point, such as under the bark or in the soil. In 10 or 12 days in warm Weather, or from 20 to 24 days in autumn, the adult insect appears and the cycle begins again by insertion of eggs in the olives. This second generation may appear in late summer or early autumn. In favorable years a third generation develops. It is the second and third genera- tions that are most destructive. In very dry years the olives are small and very hard at the time of the appearance of the first generation in early summer and very few of the insects find suitable fruit for the deposition of their eggs. Con- * Minangoin, N. Maladies et Insectes de 1 'Olivier. Compte-Kendu General de Congres Oleicole de Sousse, 1910, pp. 99, 119. CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 7 sequently, the second generation is few in numbers and the damage slight. This was the case during the 1923 season in the Seville district, where it was very difficult to find infested olives last October. In Tortosa, however, where weather conditions had been favorable to the insect, 90 to 100 per cent of the olives were infested and it was difficult to find specimens of sound fruit. Many olives contained two larvae. The danger increases as the fruit nears maturity ; hence every effort is made to harvest as soon as the olives are large enough for pickling. To allow the olives to reach the stage of maturity before pickling, at which olives are picked in California, would be very hazardous, accord- ing to growers and packers of Seville who were interviewed on this point. Although olives with a small amount of color can be used for green pickling, danger of injury by the fly is greatly increased by allowing the olives to reach this degree of ripeness. There is, there- fore, little probability that Seville olive packers will attempt to duplicate the California ripe olive pickle. Infestation is usually much less severe in the province of Seville than in the northern districts of Spain, and little effort is made to combat the pest. In Tortosa the Lotrionte method is employed. This consists in suspending in the tree a small box filled with leaves kept wet by frequent applications of syrup poisoned with arsenate of soda. The method is not very efficacious. The Berlese system consists in spraying the trees frequently with a sweetened arsenical solution. This has proved fairly satisfactory in Tuscany in Italy, where it has been applied in orchards over a very large area. The insect normally feeds on the honey dew secreted by insects or upon other sweet liquids — hence the use of poisoned syrups. The use of contact sprays is not effective. Control by insects parasitic upon the fly is under investigation but is still in the experimental stage. ' ' Opius concolor, ' ' an insect from northern Africa, gives most promise as a parasite. Dr. Silvestri of the College of Agriculture of Portici, Italy, has done a great deal of research upon the use of this and other olive fly parasites. In general, an effective method of control of the olive fly has not yet been found and its ravages are widespread and increasing. Unless an effective and economical method can be found, many olive plantings in northeastern Spain must be abandoned. Considerable damage, also, is done by the larvae of an insect that penetrates the seed of the small fruit, causing it to fall from the tree prematurely. Scale insects are common, and the honey dew secreted by them provides food for the sooty mold fungus ("la negra"), which often covers the leaves and may injure the appearance of the fruit for pickling. <3 « UNIVERSITY OF ' CALIFORNIA EXPERIMENT STATION Diseases. —Olive knot is very prevalent and undoubtedly reduces the crop.'- -One grower stated that it is frequently necessary to replace badly affected trees." Many large trees, about 10 inches or more in diameter, are affected by heart rot— many are hollow; See fig. 3. According to growers and agricultural experts interviewed, little effort is made to control these various pests and diseases, although ii Fig. 3. — Old olive tree showing heart rot. Near Seville. is believed that pruning exerts an inhibitive effect by admitting direct sunlight to all parts of the tree. Olive Varieties. — There are more than twenty varieties of olives grown commercially in southern Spain but only two are used exten- sively for green pickling. These are the Sevillano ("Queen" or "Gordal") and the Manzanillo — apparently the same as the varieties grown in California under these names. .Circular 278] olive pickling in mediterranean countries 9 The Zorzalena, a small olive similar in shape to the Mission olive, is the principal variety grown in southern Spain for oil and is some- times used for pickling for local consumption. The Rapasayo resembles the Manzanillo somewhat in form but is larger and of firmer flesh. It is not considered quite equal to the Manzanillo for green pickles but is occasionally used for green pickling, when the Manzanillo crop is small. The Cordovi is a very large olive, nearly spherical in shape, but said to be too tender for green pickling. The Murcal is a very large variety, but not so suitable as the Sevillano for green pickling, because of its large pit and poor texture. In several factories an olive very similar in appearance to the Mission of California was seen. By one pickler it was called the "Moron, ' ' but a prominent exporter stated that this name is generally used to designate a grade of Manzanillo olives. The "Moron" olive is used for pickling for local consumption. The Madrileno is a very large olive with a small pit, according to Mr. Gracey, but the writer was unable to locate this variety in Seville. It is said to be satisfactory for pickling and equal to the Sevillano in size. It is probable that one or more of the larger varieties such as the Murcal, Cordovi, Rapasayo, and Madrileno, would be suitable for ripe pickling. France. — Olives are grown in France throughout the region border- ing the Mediterranean Sea, The most important pickling establish- ments are situated in the district surrounding Nimes. Most of the fruit in other districts is used for oil-making. Varieties. — Several varieties are used for pickling. The most important according to J. Bonnet, Director of the Olive Department of the French Ministry of Agriculture, are the Picholine, the Verdale, the Lucques, and the Amellau. Others used in commercial quantities, according to A. Rolet of the College of Agriculture at Antibes, are the Salonenque, Oliviere, Espagnole (Sevillano), Bouteillan, and Gros- sanne. The Amellau is a very large olive. Samples seen in the office of J. Bonnet equalled the Sevillano in size. The Picholine Is a large olive curved near the blossom end. It is not the Redding Picholine which is a very small seedling olive distributed by mistake in, California as the Picholine. The Verdale resembles the Manzanillo somewhat in shape but is probably larger. The Lucques is elongated and much curved, i.e., somewhat crescent-shaped. It is of excellent flavor. It is probable that the Amellau and Picholine would be of value for ripe pickling in California. Most of the ripe pickles seen in Nimes were of the Picholine variety. Culture. — The culture of olives for pickles in France differs from that in Seville, particularly in regard to pruning. The trees in the 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION neighborhood of Nimes and Aix-en-Provence are pruned much more severely than in Seville. The center of the tree is kept open ; horizont rather than vertical branches are retained; the tree is "headed back" after the fashion of apricot trees by a moderate "short pruning" system ; and in addition considerable thinning is done. The pruning is annual more often than biennial. It is believed that occasional severe pruning is necessary to induce the formation of new wood and the object is to obtain a good supply of two-year-old wood, which bears Fig. 4. — Olive tree after pruning. Nimes, France. Illustrating severe pruning given once in three or four years. the fruit. See fig. 4. It must be remembered that the climate at Nimes is cooler than at Seville and the soil poorer. Therefore, it is possible that these conditions account for the difference in pruning methods in the two districts. In the Nice district on the shores of the Mediterranean the trees grow luxuriantly and become very large. Here pruning consists in "dehorning" (severely cutting back) the trees once in three or four years. Circular 278] olive pickling in mediterranean countries 11 Irrigation is seldom used in France. Fertilization, however, both with barnyard manure and commercial fertilizers is a common prac- tice. J. Bonnet stated that proper fertilization in France is essen- tial to regular bearing and that Californian growers would profit by making use of the experience of the French growers. He reports the following results of experiments to show the effect of fertilization on yields of olives in French olive groves. TABLE 1 Effect of Fertilization on Olive Yields. (After J. Bonnet) (Yields per Tree in Pounds) District Check untreated 1% lbs. ammonium Combination of Green cover crop sulfate, 2.2 lbs. preceding two plowed under. Barnyard manure superphosphate, columns No other 110 lbs. per % lb. potassium (Manure and addition tree sulfate per tree fertilizers) Villeneuve 14.08 37.07 38.72 40.04 42.90 La Fare 2.42 3.21 8.80 8.30 13.68 Ledenon 33.44 45.10 50.50 54.12 67.45 Le Luc 48.31 86.90 80.87 70.40 83.60 Fig. 5. — Typical olive tree near Florence, Italy, training of branches. Showing horizontal Mr. Bonnet points out that the amounts of fertilizing materials to be applied will vary greatly according to the age and condition of the tree, the fertility of the soil, and water supply. The proper amounts of each material must be determined for each region by trial. In experiments with the use of chemical fertilizers applied singly ammonium sulfate gave considerably greater increase in yield than did potassium sulfate or calcium superphosphate. 12 UNIVERSITY OF CALIFORNIA-^EXPERIMENT STATION Italy. — Observations made in Italy were upon the culture of oil olives rather than of pickling varieties. The principal varieties used for pickling are the Santa Catarina, a large olive grown in southern Italy and in Sicily ; the Castriciano, an olive larger than the Manzanillo but smaller than the Ascolano and somewhat like the Mission in shape; the Oliva Bianca d'Ascoli, prob- Fig. 6. — Olive grove on hillside near Viaregio, Italy. Trees planted closely together. ably the same as the Ascolano of California, although samples, said to be of this variety, seen in Rome and Florence appeared to be more enlarged at the blossom end than the Ascolano of California; .the Agostino, an olive of medium size ; the Santagatese and the Minuta. In southern Italy and Sicily the trees grow luxuriantly when properly cared for. Opportunity was not afforded to study cultural methods at first hand. In Sicily lemons have largely replaced olives and olive trees are for the most part neglected. Circular 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 12 In central and northern Italy it is customary to grow other crops such as hay, garden truck, etc., between the rows, which are planted far apart. In the Florence district the trees are small and similar in appearance to those of Nimes in France. They are severely pruned every three or four years and lightly pruned every year. Only' the Fig. 7.— Olive tree near Rome, Italy. ' Illustrating severe pruning given . once in three or four years in central Italy. horizontal and drooping branches are retained. Many of the trees are .actually . umbrella shaped. This method, of pruning facilitates picking and is believed to favor . regular bearing. (See figs. 5-8, inclusive^ )., Fertilization is regularly practiced but the trees are not irrigated. Calcium superphosphate and ammonium sulfate are the most commonly used commercial fertilizers. 14 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION PICKLING PROCESSES The processes of pickling olives in the various Mediterranean countries vary considerably according to the country, the nature of the raw material and the character of the market. For example the Spanish green olive pickling process is used for pickling olives for the Spanish export trade ; while the Greek and brine curing processes are applied largely to olives to be consumed in the countries where the olives are grown. J Pig. 8. — Olive pruning instruments. Castel Euggiero, Italy. A. SPANISH PROCESS About two months was spent in the olive districts of Spain in the study of olive pickling, and related subjects. The following description of the Spanish process is based upon observations made in the Spanish orchards and factories. Harvesting. — The picking season usually begins after September 15 and before October 1 and lasts until about November 1. The fruit is picked for green pickling after it has reached full size, but before it has ripened sufficiently to become tender. Fruit with a faint blush of color can be used, as this color disappears during pickling, but that which is entirely green or straw yellow in color is preferred. Ripe fruit is apt to soften or turn gray during pickling. CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 15 Picking. — The fruit is picked into small woven grass or wicker baskets suspended from the neck of the picker. It is done from the ground or from straight ladders. See fig. 9. Great care is taken to avoid bruising, and the fruit is selected for size and maturity as it is picked. Several pickings are necessary, as in California, in order to obtain fruit of fairly uniform quality. Fig. 9. — Harvesting Sevillano olives near Seville. Sorting. — The olives are transferred to larger baskets holding about 60 pounds. See fig. 10. These are carried by cart or on donkey-back to the field sorting tables in the orchard or to similar tables at the orchard headquarters (hacienda). Here the olives are placed on low tables, before which sit women who sort out ripe fruit, that injured by the fruit fly, very small fruit and that which is bruised. See fig. 11. The ripe and small fruit is sold to peddlers who pickle it and sell it locally — the processes of pickling used for this fruit will be described later. The damaged fruit is used for oil-making in the grower's oil factory. 16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Most packers insist that the grower carefully sort his fruit before delivery. This makes it unnecessary, in most cases, for the packer to sort at the factory before pickling. The Factories. — The factories are located either in Seville or in the small villages, such as Alcala, Dos Hermanos, San Juan, and Comas, near the city. The pickling factory usually consists of a large walled-in yard capable of holding 1000 to 3000 hogsheads of olives. At one side of the yard is a large, one-room stone building, in which are located the lye vats. Above this room or on an elevated platform in the yard Fig. 10. — At left: receiving basket used at factory. At right: field basket used in groves. I are the lye mixing and brine tanks. Some -factories* have these tanks below the floor and elevate the liquids by pump "to the vats or hogs- heads. Usually at some distance from the lye-treating room are one or more larger buildings, in which grading, pitting, stuffing (see p. 25), and packing of the pickled olives are conducted. Transporting and Receiving. — The olives are transported from the small or very hilly groves by burros. Large side-bags or ' ' angorillas ' ' hold the fruit — each animal carrying about 200 pounds. Trains of 12 to 15 burros are common. See fig. 12. From the larger groves the fruit is usually conveyed in large high- wheeled carts, the beds of which are lined with soft grass matting to minimize bruising. Flexible cloth or woven grass spouts beneath the CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 17 cart or "angorilla" permit the olives to be unloaded without much handling" and bruising. Some of the fruit is carried on flat cars or in carts in large woven grass baskets. A few motor trucks are in use, but oxen and mules are more usual. See figs. 13 and 14. Shallow, rather flexible, "two-man" baskets receive the fruit and are used in place of the lug boxes found in California factories. See fig. 10. The packers usually insist that the fruit be delivered before it has begun to heat in the field baskets after picking. Heating" is evidence of bacterial growth. This is a common source of infection and causes Fig. 11. — Sorting olives at the orchard before delivery to factory. Near Seville. sliminess and deterioration during pickling, storage, and shipment. If affected fruit does not actually spoil, at least its quality is injured. It is difficult to avoid the occurrence of such fermentation after rains have prevented delivery for several days. Much heated fruit was seen near the end of the 1923 season. Lye Treatment — Lye treatment is for the purpose of removing most of the bitterness and rendering the skin of the olives permeable to brine and fermentation organisms. In all of the factories visited, concrete or brick vats lined with cement are used as containers for the olives during the lye and washing processes. These vats are about as wide as those used in California, but are shorter and about twice as deep as ours. Iron pipe lines supply each vat with lye solution and water. See fig. 15. 18 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Granular soda lye (sodium hydroxide), of Spanish manufacture in most cases, is used in preparing the lye solution. In one factory a concentrated solution is made in a sheet-iron tank, and this solution is diluted to the desired strength in a vat below the floor level. From this vat it is pumped to the pickling vats. The strength of the lye is varied according to the maturity and variety of the olives, the temperature, and other factors. According to Gracey, the average concentration for Sevillano olives is 2y 2 ° Baume (10° salometer) and for Manzanillos 3° Baume (12° salo- meter). A sample from the Barea factory analyzed by the writer contained 1.9% sodium hydroxide, approximately 2.8° Baume (7*4° salometer). Fig. 12. — Donkey with side bags of olives. Near Seville. The olives are completely covered with the solution, and are pre- vented from floating above the surface by means of floats (usually of heavy grass matting) . They are stirred occasionally and lye penetra- tion is carefully observed by frequently cutting samples to the pit with a knife. The solution changes the flesh to a yellowish green color to the depth of penetration. The lye is allowed to penetrate about two- thirds of the way to the pit — some of the fruit will be penetrated only one-half way and some completely to the pit, but the average penetra- tion is about two-thirds of the way. No definite period of time can be given for the duration of lye treatment. According to those inter- viewed, the time varies from 4 to 8 hours, but the depth of penetra- tion and not the length of treatment is the important consideration. CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 19 Too deep penetration will destroy all of the bitterness, bleach the olives, and may result in softening". . If penetration is not deep enough, the olives will remain too bitter, even after fermentation. Untreated flesh and bitterness are necessary, in order that fermentation will be normal and the finished pickle will have the proper flavor, color, and texture. Fig. 13. — Carts used for hauling olives. Seville Fig. 14. — Transporting olives by rail to pickling factory. Near Seville. In most factories the spent lye is discarded, but in at least one large factory, that of Don Diego Gomez, the used lye solution is forti- fied by the addition of a concentrated lye solution and used a second time. 20 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Washing. — The excess of lye is washed from the olives as in Cali- fornia by several applications of cold water in which the olives stand. They are stirred occasionally to hasten and equalize leaching of the solution from the fruit. The washing period is much shorter than in California, usually not more than 24 hours — the total time required for lye treatment and washing often being less than 24 hours. The olives still contain some lye when they are removed from the vats. In all cases where the washed olives were cut and tested with dilute phenolphthalein solution, a strong reaction for free lye was obtained. Olives from four different plants were tested in this man- ner. It seems very probable that much of the trouble encountered in Fig. 15. — Pickling vats in Barea factory. Seville. Seville factories with improper lactic acid fermentation and putre- faction, may be due to insufficient removal of lye from the fruit tissue, and the writer would advise washing until all or nearly all of lye- treated flesh is free from lye. Fermentation. — The fermentation process is responsible for the special flavor of Spanish green olives. The washed olives are placed in hogsheads (puncheons or "bocoys") of about 168 gallons capacity. Each "bocoy" holds about 1016 pounds (10% "fanegas") of olives and about 800 pounds of brine for covering the olives. To fill the "bocoy" the upper hoops are loosened, one head removed, and the washed olives added to the level of the inner side of the head. The head is then replaced and the hoops tightened. The bocoys are rolled into the fermentation yard, and usually placed on wooden skids to elevate them above the wet ground. (Figs. Circular 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 21 16 and 18 illustrate a typical yard and style of cask used.) They are then filled with a heavy brine, 10 or 11° Baume (40 to 44° salometer) — two samples from different factories were found to be 11° Baume at room temperature (about 60° F.). The pickler desires bright, warm sunshiny weather, in order to hasten fermentation by increasing the temperature of the olives and brine. The weather in Seville in September and October is much warmer than in California during our olive pickling season in late October and early November ; hence, it might be necessary in this state to store the barrels in a warm room in order to promote fermentation. During fermentation the salt content of the brine decreas3S because of its dilution by the water of the fruit ; the acidity of the brine Fig. 16. — Olmeda Company's pickling yard. San Jnan, near Seville. increases rapidly by the formation of organic acids, principally lactic, by bacteria ; froth appears at the bung of the barrel and gas is given off until the fermentation is complete; while the flesh "cures" com- pletely' to "file pit and acquires a yellowish green color, a characteristic aromati'cl flavor, and a sour taste. The flesh also absorbs salt and becomes tough. Fermentation in unusually warm weather, as in September and October, 1923, may be completed in one month ; in cool weather it may require three months or longer. If fermentation is not complete a1 the time of . shipment over-seas, it will commence again when the tempera- ture becomes favorable, causing bursting of bottles or blowing out of the corks. Several weeks before the olives are to be shipped careful picklers take:small samples which they bottle, cork and incubate al about 90° F. to determine whether gas formation will occur. 22 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION During active fermentation a considerable quantity of brine is lost by frothing and as it is necessary to keep the barrels full to prevent growth of mycoderma (white film yeast) the barrels must be filled to overflowing frequently during this period by addition of fresh brine of 10 to 11° Baume. See fig. 17. Analyses which the writer was able to make of samples of brine from ' ' bocoys ' ' of olives at various stages of the curing process give an idea of the chemical changes taking place in the brine during the fermentation. Pig. 17. — Containers for brine used in filling barrels to replace brine lost during fermentation. Seville. TABLE 2 Changes Occurring in Brine During Fermentation (Sevillano Olives) Seville, 1923 Sample No. of days on olives Acidity as per cent lactic acid Salt —per cent by titration 1 Less than 2 hours Slightly alkaline 11.2 2 2 .045 8.4 3 12 .405 5.76 4* 17 .18 5 22 .765 5.26 6 25 .918 5.09 7 30 .81 8 365 (more or less) .855 .... * Sample No. 4 was slimy — evidently an unsuitable fermentation was taking place. CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 23 According to Mr. L. Boucher of the University of Seville, the salt concentration frequently decreases to 4.5 per cent. The Baume hydro- meter will indicate considerably more salt than this, because it is affected by soluble materials extracted by the brine from the fruit. Chemical analysis is the only reliable method of determining salt in such solutions. However, it is not necessary that salt determinations of the fermented brine be made; the essential condition to be deter- mined is the percentage of acid present after fermentation. If this is very low, the olives will spoil. Fig. 18. — A farmer's pickling yard. Italica, near Seville. Grading, Sorting, and Shipping. — When the fermentation is com- plete, the barrels are completely filled, sealed, and stored until needed for shipment. Properly fermented olives will keep at least two years. The shipping and packing season extends throughout the year but is most active during winter and spring. Before shipment in bulk to the United States or other foreign market, the olives are removed from the ' ' bocoys ' ' after first drawing off some of the brine and the removal of one head. They are graded roughly by hand-operated screens into three sizes. These are again carefully size graded by hand and sorted for quality. Three quality grades are made: First Quality, Second Quality, and Culls. Very little of the Second Quality and none of the culls are exported. Not more than 10 per cent of the First Quality should show slight imperfec- tions ; nearly all of the olives of the Second Quality show some sort of 24 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION imperfections; while the Culls are broken, insect-injured, and other- wise badly blemished specimens. The Culls and most of the Second Quality are sold locally. The size grades, according to W. T. Gracey, are reported as ' ' number of pairs of olives per half kilo, " as ' ' olives per kilogram, ' ' and as "olives per pound." The usual designation is number per kilogram or per "kilo." The range, according to W. T. Gracey, is 60-70 per kilogram to 400-450 per kilogram. The usual grades for Sevillanos are Large 70-80 to 90-100, Medium 100-110 to 130-140, and Small 140-200 per kilogram. The range for Manzanillos is 180- 200 to 380-400 per kilogram. One kilogram equals 2.2 pounds. After grading the olives are replaced in the barrels used during fermentation, and the original brine is returned to them. The barrels are headed up again; any brine lost during sorting is replaced by fresh brine of 10° Baume; and the barrels sealed. They are shipped by boat from the quay on the Guadalquivir River, which is at tide level. Packing in Glass and Tin. — A considerable quantity of olives is packed in glass and tin for export. In the United States most of the olives are packed in glass by the importers. For packing in tin cans the Manzanillo variety is used. These are graded for size; sorted; filled into lithographed tin cans holding from one-half to five kilograms ; the original brine is added ; and the cans are sealed with solder. They are not sterilized but are simply packed in cases and shipped without further treatment. The cans often swell slightly from gas formation, but it is said that loss from leaking or bursting of the cans is slight. These olives are shipped to Latin- American countries. Recently a satisfactory process of canning green olives has been developed in the eastern United States, according to Fitzgerald of the National Canners' Association. This consists in filling the olives into cans, brining, exhausting heavily in live steam and sealing. No further heating is required. For the fancy glass-packed fruit the olives are placed in the jars by means of a long slender wooden stick, or by long wooden or bronze tweezers. A loose pack is also made both in Spain and the United States by dropping the olives into the jars and tapping the jars lightly against the table to settle the olives. The olives, after packing by either method, are rinsed by immersing in a tank of water and inverting to drain. This is to remove bacterial cells, and other small particles adhering to the olives, in order to reduce the amount of sediment formed in the bottom of the bottle or on the olives during storage. The bottles are then filled with freshly pre- pared brine of about 9° Baume. The bottles in Spain are sealed with CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 25 long corks forced tightly into the necks. In the United States vacuum sealed jars are also used. The olives must be completely fermented before packing or gas will be formed and the corks forced from the bottles or the bottles broken. Slight gas pressure may do no harm. Pitting and Stuffing. — Stuffed Manzanillo olives are much in demand in the United States. The stuffing is done in the Spanish factories, and the olives are then barreled for export to the United States. The graded and sorted olives are first pitted by a small plunger Fig. 19. — Olive pitter. Seville. operated by a hand lever. See fig. 19. Each olive must be placed on end and carefully pitted to avoid undue tearing of the flesh and to insure a uniform appearance. Sevilla.no olives are difficult to pit, because they possess rough pits which cause a large percentage of the olives to break or tear excessively. Small strips of canned pimiento from Valencia or Logroiio, Spain, are folded and stuffed into the pitted olives by hand. These olives are then packed in barrels holding about 48 gallons ; these are filled with fresh brine (presumably 10° Baume) and allowed to stand in the sun and with the bungs open until fermentation of the pimiento flesh is complete — a month or longer is required. Unless this is done, f ermen- 26 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION tation and gas formation will occur during shipment or after packing later in bottles. The stuffed olives after arrival at American packing houses are packed in glass as described above for the whole olives. Spoilage and Deterioration. — The principal form of spoilage is known as "Zapatera." This is a bacterial decomposition resulting in such marked changes in flavor and odor that the olives are rendered unmerchantable. It usually does not become evident until the olives have been stored for several months or a year after curing. A promi- nent olive packer of Seville states that olives which have heated in the baskets or other containers before pickling are much more susceptible to this disease than are those pickled promptly after picking. He also states that the disease is very infectious and may be carried from one barrel to another in brine adhering to the fingers or sampler. This trouble is probably due in part to defective lactic acid fermen- tation and its occurrence might be greatly reduced in frequency if the brines in each of the fermentation casks were inoculated, at the time of filling, with 3 or 4 gallons of brine from a cask known to have under- gone proper fermentation, or if about 0.1 to 0.2 per cent of lactic acid were added to the brine before fermentation. The practice of leaving a considerable amount of free lye in the olives undoubtedly discourager the development of lactic acid bacteria and may favor the growth of bacteria responsible for "zapatera. " The free lye should be removed by more thorough washing. Acidification of the brine used in packing the cured olives in glass might also be advisable, since it would dis- courage the growth of putrefactive organisms. Slimy or "ropy" brines are common in many pickling yards, par- ticularly during the first month of fermentation. The sliminess dis- appears as the fermentation progresses ; nevertheless, it is evidence of growth of undesirable organisms and should be avoided, if possible. The means suggested above for control of zapatera might be effective in these cases. A white deposit is frequently found on the olives and the bottom of jars or bottles of green olives. Microscopical examination proves that in some cases the deposit consists of bacteria. These bacteria are in part those left by insufficient washing of the olives at the time of packing and in part those due to growth of bacteria in the container. In other samples the deposit does not consist of bacteria but of amor- phous particles. These may be particles of insoluble soaps formed by reaction between small amounts of soluble sodium soaps from the olive and calcium salts in the brine. Salt and water used for preparing green olives should be as free as possible from calcium and magnesium salts. CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 27 The growth of film yeasts on the brine during storage must be prevented by keeping the container full and sealed. Casts. — It was difficult to obtain estimates of cost of producing green olive pickles in Spain. However, certain costs are well known. The price paid for olives in the 1923 season varied from about 10 pesetas the fanega for oil stock to a maximum of about 30 pesetas the fanega for pickling fruit. One packer placed the average price range for pickling fruit at 20-25 pesetas the fanega. "With the peseta at 14 cents American, and the fanegas 96.8 pounds, this would represent prices of about $57.75 to $72.30 a ton for the average range and about $86.80 a ton as the maximum price. These prices are for fruit of pickling size carefully selected for size and sorted for quality before delivery. Wages for ordinary labor, according to the vice-consul, were in 1923, for men, 6 pesetas (84 cents) and for women and children, about 3 pesetas (42 cents). Those employed at piece work in packing olives (skilled labor) earn about 10 pesetas a day, according to one Seville packer. Salt at one factory costs less than $4.00 (American) a ton. W. T. Gracey placed the cost of pickling at 2 pesetas the fanega in 1918, or $8.00 a ton. This included cost of labor, lye, salt, and water but not cost of sorting, which is about $4.00 a ton. In 1922, according to W. C. Burdette, the price for green pickled olives (Queens) opened at 45 pesetas a fanega, f.o.b. Seville — a normal price (equivalent to about $130 a ton). Because of scarcity of fruit and keen competition among American importers, the price rose to 100 pesetas a fanega at the end of the season in June. This price is equivalent to about $300 a ton, f.o.b. Seville, and is considered unusu- ally high. Yet this is lower than the price often paid by the picklers in California for the fresh Sevillano olives. Evidently Spanish growers and packers can, if forced by competition, place green pickled olives on board ship at Seville at less than one-half the price of the fresh fruit in California. B. FRENCH PROCESS Several methods are in common use for preparing olives for sale in France, but for pickling olives for export one method is used almost to the exclusion of others and will be designated ' ' the French Process. ' ' This process was observed in several factories in Nimes. According to J. Bonnet,* France has an area of 120,000 hectares (296,400 acres) compared with Spain's 1,600,000 hectares (3,952,000 acres). Harvesting. — In the factories in Nimes both green and ripe pickles are prepared. As in Spain, the green fruit is harvested while still * Director of the French Olive Service. 28 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION green to straw yellow, but after it has reached full size. The ripe fruit is taken after it has acquired a cherry red to black color but before it has become too soft. Bruising must be avoided. Lye Treatment. — The lye treatment is more severe than in Seville or California. J. Bonnet of the Ministry of Agriculture informed the writer that the solution used for green olives varies from 3 to 5° Baume (12-20° salometer) according to the variety. This solution is applied in concrete vats in the Nimes factories and allowed to remain until the pit of the olive "comes free" from the flesh. Mr. Bonnet states that normally 12 hours or longer is required. The ripe olives receive somewhat weaker solutions: 2 to 3° Baume (8-12° salometer). A. Rolet of Antibes, France, recommends for the Verdale olives a solution of 6° Baume and for the other varieties 3.5 to 5° Baume. Washing. — Great care is taken to avoid exposure of the green olives to the air in order to prevent browning. Fresh water is applied and changed two or three times daily until the lye is completely removed. Brine Treatment. — The olives are not permitted to ferment and must therefore be preserved in a strong brine. In order to prevent shriveling, the concentration of salt is increased progressively at intervals of two or three days each as follows: 3°, 5°, 7%°, and 10° Baume salt solution, and finally in a solution of 12° Baume. This last solution is changed occasionally to avoid mold and bacterial decom- position. Wooden floats are used to submerge the olives. Packaging. — Wooden barrels are used for most of the fruit, which is shipped in fresh brine of 12° Baume (48° salometer). Much of the fruit is packed in glass in fresh brine of 10 to 12° Baume. Salt-cured anchovy meat is often used for stuffing the pitted olives. In a large cannery near Paris in which the packing of French cured olives was observed, the filled jars were not sterilized by heat — the strong brine was relied upon to prevent spoiling. 1923 Price for Fresh Olives. — According to Bonnet, the price for olives for pickling purposes was 2 francs a kilogram in 1923 — this is approximately 4.6 cents per pound at the rate of exchange prevailing at that time — or about $92.00 per ton. Oil olives sold at about one-half this price. C. SALT CUEING OF OLIVES For domestic consumption in Spain and Italy most olives are cured without the use of lye. There are two methods of applying the salt : dry, and in the form of a strong brine. The dry application is probably the more important. Circular 278] olive pickling in mediterranean COUNTRIES 29 The "Greek" Process. — According- to olive men interviewed in France and Italy there are several important processes in use in Greece, but the most important of these and the one in common use in northern Africa and Italy to produce ' ' Greek style ' ' pickled olives is the following : "Dead ripe" olives of large size and black color are used. These are placed in a barrel with alternate layers of salt — one pound of salt to 9 pounds of olives. The barrel is filled completely, headed up, and sealed. It is placed on its side and rolled every three or four days for the first month and once every fifteen days thereafter in order to pre- vent molding and the sticking of the olives together. The salt by osmosis draws juice from the olives and forms a heavy brine. The bitterness gradually decreases and at the end of two months the olives are usually ready for consumption. Barrels of 50 gallons are recommended. The retailer usually refreshes the olives in dilute brine for a day or two before placing them on sale. He may add herbs and other flavoring materials, such as bay leaves, fennel, sliced lemon, and sweet peppers. Usually the fruit as seen in southern European markets is drained free of brine and placed in little heaps on the market tables or in shallow baskets. In Spain. — For domestic consumption large quantities of ripe olives are cured by storage in barrels or casks in a brine of 10° Baume (40° salometer). After about one year's storage the fruit is sold. It possesses a pleasing fermented taste somewhat like that of the Spanish green cured olives. The process is to pack the fruit in barrels ; head up the barrels; fill with 10° Baume (40° salometer) brine and leave with bung open. The barrel is kept full to overflowing with brine of 10° Baume until fermentation ceases; then sealed and stored until edible — about one year. The product is plump, slightly bleached in color, and distinctly but not disagreeably bitter. Dry Salt Cure. — This was not seen, although dry salt-cured olives were observed on sale. Probably the process used was similar to that described by Caldis,* in which the olives are placed in baskets with alternate layers of rock salt and allowed to stand until edible. The brine drains through the basket as rapidly as it forms. These olives are often preserved in olive oil or soaked in oil before serving. * Caldis, A. Curing Olives in Greece. Proceedings of Olive Processors' Conference, Berkeley, 1923, p. 29. 30 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION D. MISCELLANEOUS PEOCESSES Water Curing. — This is one of the favorite methods of removing the bitterness in the Seville district. It is also used in France and Italy. In Spain the olives are often slit lengthwise to the pit in three or four places ; this is done by hand or by means of three or four sharp blades mounted around a hole in a board. In the latter case the olive is slit by forcing it through the hole past the cutting surfaces. Slitting facilitates extraction of the bitterness. A more common method is to crush the olives lightly either with a wooden mallet or between wooden rollers so adjusted that the flesh of the olive is broken without breaking the pit. The slit or crushed olives are placed in tubs or open barrels of water, which is changed three or four times daily until the fruit is edible. The writer was told by one pickler that washing for about two weeks was required. Flavoring and Preserving. — If the olives are to be consumed at once, a light brine acidified with vinegar is added. Sliced sweet peppers, garlic, fennel, whole pepper seed, whole mustard seed, bay leaves, and other spices are added in most cases. After standing several days, the olives are ready for sale. Their life is short — spoiling soon begins unless a strong brine of 10 to 12° Baume or a high concen- tration of vinegar is used. This type of pickle was purchased in Seville in November, 1923, at retail for 7 cents a pound. The flavor was pleasing. This pickle is a favorite with Spanish consumers. Pickles of this type were found to be common also in Palermo and Messina in Sicily, in Florence and Lucca in Italy, and in Marseilles in France. Often, olives cured by the Spanish green process (usually culls or seconds from the packing houses) are broken after pickling and are sold in a vinegar brine flavored with garlic, peppers, and spices. While these products would probably not be practicable in America it is probable that the following modification would have possibilities. Pickle the green fruit by one lye, no exposure process. Crush lightly. Can in 4° Baume brine containing vinegar, sliced sweet peppers, bay leaves, fennel, and other suitable spices, and sterilize for sale to the Latin- American trade. Another product of a type somewhat similar to the crushed olives is made in the United States from the culls from imported Spanish green olives. The olives are pitted and ground coarsely for use in sand- CIRCULAR 278] OLIVE PICKLING IN MEDITERRANEAN COUNTRIES 31 wiches and as a relish. This product is excellent without mixing with other materials, but is improved by addition of pimiento. If California olive packers are to seriously consider the preparation and sale of small olives in the form of a relish or butter it is advised that experi- ments be made in which the fruit is first pickled by the Spanish green olive process. The olives might then be made into a rather coarse "butter" or sandwich filler by means of a tomato pulper equipped with a very coarse screen or by other suitable mechanical device. If pimiento is added it would be necessary to sterilize the product. How- ever, on account of the high acidity of the green pickles sterilization should not be difficult. A satisfactory imitation of the green oliv butter has been prepared in the Fruit Products Laboratory of the Col- College of Agriculture by first pickling the olives by the ripe process ; pitting; grinding coarsely; adding 10% by weight each of ground pimiento and horseradish and 20% of ground, sour cucumber pickles. This product is sour but the olive flavor predominates. It is not injured in flavor by sterilization at 240° Fahrenheit for 40 minutes. Dried Olives. — A popular olive "pickle" on the Italian table is the dried olive. A recipe given by a cook at Castel Ruggiero, near Florence, was as follows : ' * Use ripe olives. Dip in boiling water 2 or 3 minutes. Dry on cloth in the sun or, if the weather is unfavorable, in the oven. Store in baskets in a dry place. ' ' A variation consists in dipping in boiling water ; soaking in brine a day or two ; and then drying. SUMMARY AND CONCLUSIONS 1. Cultural Methods. — The methods of growing of olives for pick- ling purposes in Spain, France and Italy are distinctly different from those in use in California. In Europe the trees are pruned more severely and fertilized more regularly than in California. Irrigation even in semi-arid localities is much less common than in California. California growers should test the southern European methods of pruning and fertilization in order to ascertain whether they would induce more regular bearing than exists at present. More European olive sections could undoubtedly use irrigation to advantage. 2. Olive Fly. — The olive fly is a serious menace to the olive industry of southern Europe. All reasonable precautions should be taken to exclude it from California, Satisfactory control by sprays or other means has not been perfected although spraying frequently with a 32 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION sweet arsenical spray has given fair control in Italy. Olives in southern Spain to be used for pickling are harvested before full maturity in order to avoid damage by the olive fly. 3. Varieties for Pickling. — Several European varieties not now grown commercially in California might prove valuable in this state for ripe pickling. These are : (a) Spanish varieties : Murcal, Cordovi, Madrileno, and Rapasayo ; ( o ) French varieties : Amellau, Picholine and Lucques ; and (c) Italian varieties: Santa Catarina, Castriciano and the Ago- stino. Trees of the Santa Catarina and the Lucques are growing at the University Farm or elsewhere in the state. Attempts are being made to introduce grafting wood of the other varieties. 4. Spanish Green Olives. — The Spanish green olive pickling pro- cess was carefully studied in the factories in and near Seville and is described fully in this publication. It is believed that California picklers could utilize a considerable portion of the crop of some varie- ties for green pickling. It might be necessary to modify the process to suit our temperature and other conditions. Green olives in the eastern United States are made into a relish or sandwich filler by coarsely grinding the pitted olives. This is very popular. Perhaps our small olives could be pickled by the green process; coarsely pulped and pitted mechanically to give such a relish ; or the ripe pickled Oliver similarly pulped and flavored to give a relish with a flavor similar to that made from the green olives. 5. French Process. — The French process is essentially the old California process in which the olives are treated with one lye solution only, washed free of lye and preserved in a very strong brine. Its use probably should not be revived in this state. 6. Greek Process. — The Greek process as applied in southern Europe and northern Africa consists in curing the olives in sealed barrels. Ten per cent salt is mixed with the olives. This extracts juice from the fruit and forms a heavy brine. This process may be an improvement upon that in use in California for preparing salt-cured olives. 7. Other Processes. — Olives are slit or crushed, leached free of bitterness in water and then stored in dilute vinegar or brine flavored with spices and sweet peppers. These are popular for local sale in Europe. Perhaps spiced, crushed, canned and sterilized pickled Oliver could be sold in America to people of southern European origin. Dried olives are also common and popular as are also those cured in 10° Baume brine without the addition of lye. Circular 278] olive pickling in mediterranean COUNTRIES 33 SELECTED REFERENCES Spanish, French and Italian publications on Olive Culture, Oil Making, and Pickling are very numerous; a complete list would be of little value to California growers and packers; therefore, a few selected references only are given. Spanish Green Olives — 1. Wilbur T. Gracey. Olive Growing in Spain. Special Consular Report No. 79. 34 pages. 1918. Obtainable for 5 cents in coin from the Superintendent of Documents, Government Printing Office, Washington, D. C. 2. El Aceite de Oliva. Resumen hecho por la Junta Consultiva Agronomica. Madrid, 1923. Obtainable from Ministerio de Fomento, Madrid, Spain. Published by Hijos de M. C. Hernandez, Libert ad 16, Madrid, Spain. Contains a great deal of information on the grow- ing of olives in Spain, pickling of olives, and the manufacture of oil. In Spanish. French Process and Other Processes — 1. J. Bonnet. L'Olivier, 1924. Published by J. B. Bailliere et Fils, 19 Rue Hautfeuille, Paris. Price, 10 francs plus postage, a total of about 15 frances, about 95 cents, American. Written by the foremost olive expert in France. 2. A. Rolet. Les Conserves de Fruits. 449 pages, 171 illustrations, 1913. Published by J. B. Bailliere et Fils, 19 Rue Hautfeuille, Paris. Original price, 6 francs; probably not less than 15 francs at present. 3. Pour 1 'Olivier. Comptes rendu des Travaux du V° Congres International d'Oleiculture, Marakech et Rabat, 1922. Published by Libraire de l'Institut Agronomique, 58 Rue Claude Bernard, Paris. Price, 50 1 francs. This is the proceedings of the Fifth International Congress of olive culture. The proceedings of the Sixth Congress is now also available at the above price. Each contains numerous papers by experts on all phases of the olive industry. In French. 15m-9,'24 STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION No. 253. Irrigation and Soil Conditions in the Sierra Nevada Foothills, California. 261. Melaxuma of the Walnut, "Juglans regia." 262. Citrus Diseases of Florida and Cuba Compared with those of California. 263. Size Grades for Ripe Olives. 268. Growing and Grafting Olive Seedlings. 273. Preliminary Report on Kearney Vine- yard Experimental Drain. 275. The Cultivation of Belladonna in Cali- fornia. 276. The Pomegranate. 277. Sudan Grass. 278. Grain Sorghums. 279. Irrigation of Rice in California. 280. Irrigation of Alfalfa in the Sacramento Valley. 283. The Olive Insects of California. 285. The Milk Goat in California. 286. Commercial Fertilizers. 287. Vinegar from Waste Fruits. 294. Bean Culture in California. 298. Seedless Raisin Grapes. 804. A Study of the Effects of Freezes on Citrus in California. 312. Mariout Barley. 317. Selections of Stocks in Citrus Propa- gation. 319. Caprifigs and Caprification. 321. Commercial Production of Grape Syrup. 324. Storage of Perishable Fruit at Freezing Temperatures. 325. Rice Irrigation Measurements and Ex- periments in Sacramento Valley, 1914-1919. 328. Prune Growing in California. 331. Phylloxera-Resistant Stocks. 334. Preliminary Volume Tables for Second- Growth Redwood. 335. Cocoanut Meal as a Feed for Dairy Cows and Other Livestock. 336. The Preparation of Nicotine Dust as an Insecticide. 339. The Relative Cost of Making Logs from Small and Large Timber. 343. Cheese Pests and Their Control. 344. Cold Storage as an Aid to the Market- ing of Plums. BULLETINS No. 347. 348. 349. 350. 351. 352. 353. 354. 355. 357. 358. 359. 860. 361. 362. 363. 364. 366. 367. 368. 370. 371. 372, 373. 374. 375. 376. for and and Cali- Almond Pollination. The Control of Red Spiders in Decidu- ous Orchards. Pruning Young Olive Trees. A Study of Sidedraft and Tractor Hitches. Agriculture in Cut-over Redwood Lands. California State Dairy Cow Competition. Further Experiments in Plum Pollina- tion. Bovine Infectious Abortion. Results of Rice Experiments in 1922. The Peach Twig Borer. A Self-mixing Dusting Machine Applying Dry Insecticides Fungicides. Black Measles, Water Berries, Related Vine Troubles. Fruit Beverage Investigations. Gum Diseases of Citrus Trees in fornia. Preliminary Yield Tables for Second ftrowth Redwood. Dust and the Tractor Engine. The Pruning of Citrus Trees in Cali- fornia. Fungicidal Dusts for the Control of Bunt. Turkish Tobacco Culture, Curing and Marketing. Methods of Harvesting and Irrigation in Relation to Mouldy Walnut6. Bacterial Decomposition of Olives dur- ing Pickling. Comparison of Woods for Butter Boxes. Browning of Yellow Newtown Apples. The Relative Cost of Yarding Small and Large Timber. The Cost of Producing Market Milk and Butterfat on 246 California Dairies. Pear Pollination. A Survey of Orchard Practices in the Citrus Industry of Southern Cali- fornia. Results of Rice Experiments at Cor- tena, 1923. Sun-Drying and Dehydration of Wal nuts. CIRCULARS No. No. 70. Observations on the Status of Corn 161. Growing in California. 164. 87. Alfalfa. 165. 111. The Use of Lime and Gypsum on Cali- fornia Soils. 166. 113. Correspondence Courses in Agriculture. 167. 117. The Selection and Cost of a Small 170. Pumping Plant. 127. House Fumigation. 172. 129. The Control of Citrus Insects. 173. 186. Melilotus indie a as a Green-Manure Crop for California. 174. 144. Oidium or Powdery Mildew of the Vine. 178. 151. Feeding and Management of Hogs. 179. 152. Some Observations on the Bulk Hand- ling of Grain in California. 184. 158. Announcement of the California State 190. Dairy Cow Competition, 1916-18. 193. 154. Irrigation Practice in Growing Small 198. Fruit in California. 199. 155. Bovine Tuberculosis. 201. 157. Control of the Pear Scab. 202. 158. Home and Farm Canning. 160. Lettuce Growing in California. 203. Potatoes in California. Small Fruit Culture in California. Fundamentals of Sugar Beet Culture under California Conditions. The County Farm Bureau. Feeding Stuffs of Minor Importance. Fertilizing California Soils for the 1918 Crop. Wheat Culture. The Construction of the Wood-Hoop Silo. Farm Drainage Methods. The Packing of Apples in California. Factors of Importance in Producing Milk of Low Bacterial Count. A Flock of Sheep on the Farm. Agriculture Clubs in California. A Study of Farm Labor in California. Syrup from Sweet Sorghum. Onion Growing in California. Helpful Hints to Hog Raisers. County Organizations for Rural Fire Control. Peat as a Manure Substitute. CIRCULARS — Continued No. 205. Blackleg. 206. Jack Cheese. 208. Summary of the Annual Reports of the Farm Advisors of California. 209. The Function of the Farm Bureau. 210. Suggestions to the Settler in California. 212. Salvaging Rain-Damaged Prunes. 214. Seed Treatment for the Prevention of Cereal Smuts. 215. Feeding Dairy Cows in California. 217. Methods for Marketing Vegetables in California. 219. The Present Status of Alkali. 220. Unfermented Fruit Juices. 228. Vineyard Irrigation in Arid Climates. 230. Testing Milk, Cream, and Skim Milk for Butterfat. 231. The Home Vineyard. 232. Harvesting and Handling California Cherries for Eastern Shipment. 233. Artificial Incubation. 234. Winter Injury to Young Walnut Trees during 1921-22. 235. Soil Analysis and Soil and Plant Inter- relations. 236. The Common Hawks and Owls of Cali- fornia from the Standpoint of the Rancher. 237. Directions for the Tanning and Dress- ing of Furs. 238. The Apricot in California. 239. Harvesting and Handling Apricots and Plums for Eastern Shipment. 240. Harvesting and Handling Pears for Eastern Shipment. 241. Harvesting and Handling Peaches for Eastern Shipment. 243. Marmalade Juice and Jelly Juice from Citrus Fruits. 244. Central Wire Bracing for Fruit Trees. 245. Vine Pruning Systems. No. 247. 248. 249. 250. 251. 252. 253. 254. 255. 256. 257. 258. 259. 260. 261. 262. 263. 264. 265. 266. 267. 268. 269. 270. 271. 272. 273. 275. Colonization and Rural Development. Some Common Errors in Vine Pruniag and Their Remedies. Replacing Missing Vines. Measurement of Irrigation Water on the Farm. Recommendations Concerning the Com- mon Diseases and Parasites of Poultry in California. Supports for Vines. Vineyard Plans. The Use of Artificial Light to Increase Winter Egg Production. Leguminous Plants as Organic Fertil- izer in California Agriculture. The Control of Wild Morning Glory. The Small-Seeded Horse Bean. Thinning Deciduous Fruits. Pear By-products. A Selected List of References Relating to Irrigation in California. Sewing Grain Sacks. Cabbage Growing in California. Tomato Production in California. Preliminary Essentials to Bovine Tuber- culosis Control. Plant Disease and Pest Control. Analyzing the Citrus Orchard by Means of Simple Tree Records. The Tendency of Tractors to Rise in Front; Causes and Remedies. Inexpensive Labor-saving Poultry Ap- pliances. An Orchard Brush Burner. A Farm Septic Tank. Brooding Chicks Artificially. California Farm Tenancy and Methods of Leasing. Saving the Gophered Citrus Tree. Marketable California Decorative Greens.