UNIVERSITY OF CALIFORNIA. ABRWULTURAL EXPERIMENT STATIOH. BULLETIN NO. 54. Condensed Grape Must and Its Uses. the use ot the ordinary vacuum pan, how- ever, the process is of necessity interrupted The evaporation of mast for the parpose of from time to time, for the discharge of the con- rendering it cheaply transportable and capable '^^^^H^ product. It is evidently very desirable, . , 7. •, M . . , lor this as well as for many other purposes, to of almost mdefinite conservation, is an industry ,^ake the evaporating process a continuous one, of quite recent origin. Cider boiled down to as is done in the distillation of wines etc., by the consistency of jelly has been in the Eastern "^e of the De osne or Egrot apparatus, markets for some time, has found considerable This object has been very fully and couveniently ^ _ , . attained by the "i aryau evaporator, in which acceptance for table nse, and has formed a the must to be condensed flows through a means of utilizing fruit which, from various system of pipes that is suriounded, throughout causes, could not find its way to a profitable l^'ogth, by dmilar but vider pipe, forming a ^ 1 4. rp. „ ^ r .X Steam jacket by which the interior pipe is uni' market. The evaporation of grape must for formly heated throughout its length!^ By con- similar uses was begun by the late Mr. J. C. necting the latter with an air exhaust, as in the Weinberger, of St. Helena, at the time when it common vacuum pan, the boiling and conse- seemed necessary to find other outlets than '1"^"* evaporation of the must (or other liquid) , . . , , 1 - ^ takes place at so lOw a temperature that its wme making for the grape product oi Califor- nature is changed hut very little. It does not nia. Samples of the syrup then made are pre- acquire a '*cooked" taste, but simply loses its served at the University, and the results of its water; and when the latter is afterwards again examination were given in the report of the added to the proper extent, a must is produced agmultural department of the University for which few persons would distinguish from the 1877. Mr. Weinberger had, it seems, clarified freshly pressed product. Those desiring to see the grape juice just as is done in the case of grape juice supersede fermented wine in daily cane juice, with lime; thus throwing down all use could haidly find or desire a more complete the tartaric acid in the insoluble form, together solution of the problem of i?8 preservation for with other non saccharine ingredients. The use throughout the year. must thus treated formed, after boiling down, at The evaporated must issues from the appa- first a dark, molasses-like syrup, which soon ratus in the form of a brownish syrup; but on became so much filled with granulated grape cooling, it after some time congeals into a thick sugar as to render it wholly or partially solid, granular paste, possessing, in ihe case of the In that form it was unacceptable to the trade, Muscat, Catawba and similarly scented varieties, though very pleasant to the taste. From that the distinct flivorof the grape. The sweet, cause, as well as from the revival of the wine aciduous paste is quite tempting for table use | interest that soon followed, the manufacture in place of other sweetf; but it must not be i was abandoned. forgotten that it contains enough of cream of Within the last few years the evaporation of tartar to form quite a purgative dose if in- ' must has been prominently broached in Europe dulled in too freely. ' as a means of supplying to distant wine-making During the past vintage season a '*Yaryan" districts the ingredients needed to make up the evaporator was operated for some time at the deficiencies in the quality or quantity of their Bugby vineyard near Folsom, by Mr. T. D. wines, from regions where wine making could Cone, the agent in charge of its introduction in not be as advantageously carried on. It was at California. The must from about 60 tons of once understood that in order to maintain in grapes of various kinds was evaporated and the. evaporated must the conditions for a heal- shipped East to the "Lenk Wine Company" of thy fermentation, it is necessary to conduct the Toledo, Ohio, who fermented it in various condensing process at the lowest temperature ways, partly by itself, partly with other grapes possible; and the vacuum pans employed in of Eastern growth, in order to test itil behavior sugar rehning weie naturally resorted to for the in wine-making. Two series of similar tests purpose. Excellent results were reported from were made in California, one by the Viticul- the use of must so condensed, in the " correc- tural Commission and one at the University tion ' of more or less faulty musts or wines. It laboratory. In the latter only white wines thus becomes possible to apply the principles of were made, and from Zinfandel must, no other •!u V"^ '•petiotizmg" processes, being available at the time in suflicient quant ty. without the use of any ingredients foreign to The composition of the condensed musts used in t"®__^£*Bl' . . the latter experiments was as follows; Solid Contents Zinfandel, Ist crop 74.80 Zinfantlel, 2d cr.»p 68.00 Acid as Ash Tartaric 1 511 .967 1.639 .634 No analyses of the original grapes had been made; but it is evident from the figures of the table that in the first-crop must, the con- densation had been to the extent of about 3 to 1, which agrees with Mr, Cone's estimate: while in the second-crop must the evaporation had stopped short of that proportion, and the mass was noticeably more liquid. The char- acteristics of the second* crop are apparent in the high acid and low ash, as compared with the same data in the first crop. Under the microscope, both alike appear as a mass of minute glucose crystals, mingled with those of cream of tartar, and numerous fruit cells, partly whole, partly ruptured; showing that the must had not been filtered before evaporation. On October 27th, 1885, a quantity of the first-crop condensed must was diluted with water so as to reduce the solid contents to 24.13 per cent, making up five gallons of must, and was placed in the fermenting room at 70 degrees, without the addition of anything to start fermentation. Frothing and fermenta- tion commenced within 24 hours, and on Oct. 29th, reached the maximum temperature of 83 degrees. The temperature then fell slowly until on Nov. 10th, it reached the cellar tem- perature of 70 degrees, two weeks from the beginning. The wine was racked from the lees on Nov. 24th, fairly clear. A precisely similar experiment was started on November 6th, with must of the second crop, diluted to practically the same sugar con- tents. Here also, the fermentation started spontaneously within 18 hours of the setting* It seemed rather more vigorous than in the first- crop must; reached the same maximum temper- ature of 83 degrees on November 9fch, but had already fallen to the cellar temperature of 69 degrees on November 12fch, thus completing its active fermentation much more quickly than the first-crop must. It was racked at the same time as the latter — on November 24th — quite clear. A third fermentation experiment was made with the must of the second crop, diluted, as before, but filtered before setting for fermenta- tion on November 21st. The starting of the fermentation seemed in this case to be as prompt as before, but it progressed very slowly. The keg was therefore transferred to a warm chamber and there completed the fermentation,, under an external temperature of 80 degrees, by December 14th, when the wine was racked from the lees. It showed a faint milky tur- bidity, which it has ever since maintained. Two blends were also made — one with 50 per cent of Burger, from D. C. Feely, Patchen; an- ; other, with two and one-hftlf per cent of I Verdal, purchased in the market, and which was first allowed to start into active fermenta- tion before blending. In both cases the course of the fermentation was very nearly the same as in the unblended must of the same (Brst) crop. It appears from the above experiments that the condensed must starts its fermen ation as readily as the fresh, but that for this purpose it should remain unfiltered, retaining the me- chanically floating matter that runs with it from the press. The second-crop must, with high acid, completed its fermentation quite as rapidly as any fresh must; but in the first-crop product the course of the fermentation seemed to lag somewhat. In taste the white Zinfandel wines thus made are remarkably neutral. The character of tiie grape, such as is perceived in white wines made from fresh must, is nearly or quite irrecogniz- able. Such neutral wine would, of course, find its good use in blending; but samples of Chasse- las, Muscat and Catawba wines made by the Lenk Company, at Toledo, do not exhibit this neutrality, but possess, in a marked degree, the peculiar aromas of the respective grapes. It will therefore be necessary to determine for each grape variety the effect produced upon the wine by the previous condensation of the must, and govern its proper blends accordingly. The tendency to a lagging ot the fermentation in the case of a first-crop must, alluded to above, with a certain lack of character observ- able in the young wines, alone points to the pro- priety of using the condensed must and wines mainly in blends; preferably of course in " grape blends," made before fermentation with the grape that is intended to give the prominent character to the wine. There is another point which thus far is merely a probable presumption from the short experience had, viz., that when fermented by themselves, the condensed musts have a tendency to go into "milksour- nesp," which is slightly perceptible in several of the samples, both in those fermented here and in those brought from the East. The second- crop -must fermented at the University is, how- ever, perfectly sound in every respect; and it can scarcely be doubted that a little study of the matter will teach how to counteract this tendency and thus obviate the possible danger to the soundness of wines. Taking this for granted it is not easy to over- estimate the possible importance of the con- densed must industry to the grape-grower. It enables the producer to transform his crop into a compact, merchantable product even more quickly than is done in raisin making, and to preserve it indt finitely for a variety of purposes, some of which may yet be developed. The invalid desiring to use the "grape cure" can have it where and whenever he wants it; and grape must can be dispensed at all seasons, from the torrid zone to the Arctic, at a cost originally much less than lime juice, and at one-tMfH the cost of transportation and pack- ages. Winemaking can be transferred from unfavorable localities and seasons to favorable ones; and a supply of condensed must, made up early in the season or kept over from the previous year, could be used to correct defects of fermentation such as occurred daring the past vintage, to overcome the **arrest of fer- mentation" so much complained of, and which has given rise to so much unsound wine. Expe- rience will soon show what kinds of must it would be especially desirable to devote to such purposes, and it id extremely probable that some grape varieties now little valued, but very productive, would be habitually utilized in this way, whether at home or after exportation. It still, of course, remains to be seen how far such advantages as these can be realized on the large scale, taking into consideration the cost and producing capacity of the apparatus. From the tact that it is now extentivtly employed in the utilization of sueh a Jow-value by-product as slaughter-house tankage, it would se» m prob- able that it would not fail of satibfactory per- foimance in the case of grape juice. It is to be hoped that a more extended experience during the corning vintage, both as regards the per- formance of the apparatus and the utilization of the product, set at rest all the more impor- tant questions connectfd with the subject. The table below shows the composition of some of the wines made from condensed musta,. ADalyses of Wines from Condensed Must, Vintage of 1865. WINBS MADE AT UNIWR8I1Y LABORATORY. 24.13 .4^8 .312 2.30 .481 .244 ■24.02 .579 .2-24 2.15 .525 .140 nie as No. 40 2.60 .57G .187 WINES MADE BY LENK WI.NE CO , No. 31— l8t Crop ( i Mu9l Zinfandel ) i Win< No. 40.- 2d Crop ( Musi Zinfandt 1 ( Win' No. 41.— 2d Crop f Mus' Zinfandel, filtrd) iWin. I Alcohol. 24.13 trate 11.23 24.02 none 10.54 24.02 none 10.54j Chasselas iWint Aiission Wint Muscat Wint Catawba Wine 2.58,.495i.f90 2.58;.436 . 300; 4.20|.750l.290' 2.C0;.69(j .250 13. 7S 13.00 13.00 TOLEDO. 10. 81113. 27 9.92 12.36 8.84 11.00 10.26il2.73 some some mu'h none It will be seen that in their composition these wines do not differ from those that might be looked for from fresh juice of the same grape varieties, save that tne last two show an ab- normally high acid. In the case of the Muscat sample this is acconripanied by veiy distinct "milksournesp," which is aUo perceptible in the Catawba, and very lightly in the University sample No. 31. That this fault is doubtless avoidable has been stated above. E. W. HlUJARD. Berkeley, April 23, 18S6.