SB 275 .G23 ^opy 1 I*. S. DEPARTMENT OF AGRICULTURE. BUREAU OF PLANT INDUSTRY— BULLETIN NO. 100, PART 17. B. '!". GALLOWAY, I Me/ of Bureau. lETHODS OF TESTING THE BUKNING QUALITY OF CIGAK TOBACCO. WIGHTMAN W. GARNER, Scientific Assistant, Plant Breeding Investigations. Issued June 9, 1906. WASHINGTON: GOVERNMENT PRINTING OFFICE, 1906 1tonoflr»pt» i^p t> CONTENTS. Page. Introduction .5 The smoking test 7 The effects of the filler, the binder, and the wrapper on the burn of the cigar. 9 Testing the capacity for holding fire and the evenness of the burn 11 Testing the burn of cigar-filler tobacco 14 3 ILLUSTRATIONS. PLATES. Page. Plate I. Variation in burn of wrappers due to different tillers 14 II. Variation in burn of iillers due to different wrappers and binders.. 14 TEXT KICI RES. Fig. 1. Apparatus for testing the burning quality of cigars 8 2. Apparatus for'testing the burning quality of wrapper tobacco 12 3. Construction of form on which leaf is wrapped for use in apparatus shown in figure 2 12 4 METHODS OF TESTING THE BURNING QUALITY OF CIGAR TOBACCO." INTRODUCTION. As has been pointed out in previous publications of the Bureau of Plant Industry, a systematic effort is being- made to improve the qual- ity and yield of the tobacco crop by employing- the latest and most approved methods of selection in the old varieties and by creating and establishing- new strains possessing to a marked degree those characteristics most to be desired in the various classes of tobacco which the market demands. This work necessitates the careful test- ing of a large number of types, as well as many individual selections from each of these types, and for this reason it is very desirable to have at our command methods capable of showing with certainty even slight "differences in the essential qualities of the various samples to be examined. It is our purpose to make a careful study of the subject of testing tobacco from a practical standpoint, as well as the relation of the chemical composition of the leaf to its good and bad qualities. In judging the merits of a cigar tobacco, due regard must be had for the particular use for which it is intended, since the finished cigar consists of three distinct components — the tiller, the binder, and the wrapper — each of which must possess certain characteristics. The «In the tobacco breeding experiments conducted by the Plant Breeding Investiga- tions of the Bureau of Plant Industry, particular attention is being given to the improvement of cigar tobaccos, including specially high-grade wrapper and tiller types. In connection with these experiments, which are being conducted by Messrs. A. D. Shamel and W. W. Cobey of this Office, it has been found necessary to emu- pare the characters of a large number of selected individual plants to determine which ones are superior in their important characters. The means and methods heretofore used in making such comparative tests were very imperfect, and one important preliminary part of the work is to devise special pieces of apparatus which will enable accurate tests to be made. The devices described by Dr. Garner in the present paper it is believed will greatly facilitate such testing and add to the accuracy of the results. The preliminary notes given by Dr. Garner on the influence of wrapper, binder, and filler on the "burn" of cigars open up an important field of investigation in connection with the testing and breeding of different types of tobacco. — Herbert J. Webber, Physiologist in Charge of Plant Breeding Investigations. 6 TESTING THE BURNING QUALITY OF CIGAR TOBACCO. filler must have, above all else, a tine flavor and aroma and a good "burn." In the case of the wrapper leaf there are a number of requirements to be met, among which are sufficient elasticity, proper color, size, and shape, fineness of veins, freedom from objectionable flavor and taste, a fiwe "grain," and a good burn. Many of these qualities can be determined by simple inspection, without the use of any specific tests, while others require special laboratory methods. The present article has to do only with the practical methods of testing the burn, deferring to a later day a consideration of the chemical characteristics of the tobaccos which have been tested. There are several elements which go to make a good or bad burn, chief of which are the capacity for holding tire, the evenness of the burn, the color of the ash and its firmness, the coaling or carboniza- tion, and the " puckering " of the leaf immediately in advance of the burning zone of the cigar. The final test of any cigar tobacco must, of course, rest in the smoking of the manufactured cigar, but, while this gives a direct means of determining the character of the ash, it does not furnish accurate information as to the evenness of the burn or the fire-holding capacity of any one of the components of the cigar except with reference to the other two particular components used in the experiment. This is particularly true of the wrapper, as was shown by special experiments carried out to observe the effect of using different fillers and binders with the same wrapper. The result of these experiments will be more fully discussed below. Again, it should be remembered, in this connection, that cigars made by the same workman and from the same lot of tobacco often vary widely in their burn owing to the impossibility- of avoiding unevenness in the tiller, and this source <>!' error can only he eliminated by several times repeating the experiment. It is evident, therefore, that, in order to get reliable data concerning the relative merits of different wrappers with respect to their burning qualities, the cigar test must be supple- mented by some other method capable of giving sharp distinctions as to the fire-holding capacity and evenness of burn. A method which has long been in use is to ignite the leaf by means of a lighted cigar or a slow-burning match devised by Nessler," and note the number of seconds during which it continues to glow. The mean of several tests is taken as a measure of the capacity for holding fire; but the variation in the results obtained, even upon a single leaf, is so great that little reliance can be placed upon the figures except in a very general way. In this method no account is taken of the area of the leaf burned, and the wide differences obtained on a single leaf are due principal^ to the fact that frequently the ignited zone soon ceases to glow except for one or more very small streamers, which «Landw. Vers. Stat. ; XI, 399. THE SMOKING TEST. 7 continue to burn for u much longer period, thereby giving results altogether out of proportion to the true burning qualities of the tobacco in question. Another serious objection to the method is found in the interference of the veins of the leaf; for it seldom happens that the glow can cross these veins except around the outer edges of the leaf, while in the cigar the veins always run longitudinally and so do not interfere with the burn. The rational procedure would seem to be to test the burn of the leaf when wrapped in some such form as is actually found on the cigar, but without the use of binder or tiller. We have devised a method of this kind in which the leaf, after being properly wrapped and dried, is burned with the aid of a slow current of air. The current of air com- pensates in a measure for the absence of the tiller and binder, while its use obviates the unavoidable irregularities of the latter. A detailed description of the apparatus used and the method of carrying out the operation will be found on page 11. This test, combined with the smoking of the cigar, has enabled us to accurately classify a large number of samples of wrapper leaf with respect to their burning qualities. THE SMOKING TEST. It is evident that no two persons would smoke a cigar in exactly the same way, nor would the same individual smoke two cigars under exactly similar conditions. It is necessaiw, therefore, to use some means of smoking the cigars artificially in order to eliminate the per- sonal equation and secure uniformity of conditions. Dr. E. II. Jen- kins, in the Annual Keport of the Connecticut Agricultural Experi- ment Station for 1892, has described an apparatus for smoking cigars which was devised by Mr. S. L. Penfield, of Yale University. The " pull 51 on the cigar is secured by means of an aspirator which is tilled b} T a continuous inflow of water and emptied at regular intervals by a siphon. We have modified this apparatus in a number of details in order to adapt it to our needs, and we give herewith a description of the form and dimensions which we have finally adopted for use in our investigations. In this apparatus as many as four cigars may be smoked simultaneously, while held in such a position that they may be readily compared throughout the operation. By reference to the accompanying illustration (tig. 1) it will be seen that the holders (a, I, c, and d) for the cigars are so arranged that they all lie in the same vertical plane, each one 2 inches above and having its horizontal arm 2 inches shorter than the next lower. A screen with a white covering is placed immediately in the rear of the holders to serve as a background, thereby facilitating observation of the character of the ash. Between the flask bearing the holders and the aspirator and connected with these by means of glass tubing is a 8 TESTING THE BURNING QUALITY OF CIGAR TOBACCO. check valve consisting of a T-tube (e), the lower arm of which dips beneath the surface of the water in a suitable vessel (/), thus prevent- ing a backward draft through the cigars while the aspirator is filling. The smoke which escapes through this valve has a very disagreeable odor; hence, it is well to use a bottle fitted with a stopper with two holes, through one of which passes the lower arm of the T-tube {). The tube furnishing the water sup- ply is connected with a reservoir provided with a constant-level attach- ment, To the lower end of the small arm of the siphon is attached a glass tube (m) bearing a small bulb which materially assists in break- ing the flow of the water at the moment the aspirator is emptied. The tubing connecting the parts of the apparatus should not be less than EFFECTS OF FILLER, BINDER, AND WRAPPER ON BURN. 9 6 to 8 ram. internal diameter; otherwise the tubes will frequently become clogged by the, condensation products of the smoke. The container for the cigar holders (n) is filled about two-thirds full with dilute sul- phuric aeid, which serves as an acid wash for the smoke, retaining the organic bases and thereby further helping to prevent the choking up of the machine. The lower ends of all the cigar holders should, of course, extend to exactly the same depth below the surface of the aeid. In the machine which we now have in operation, the relation between the short arm of the siphon and the internal diameter of the aspirator is such that the volume of water delivered at each emptying of the latter is 600 e.c. This corresponds to an actual capacity of about 450 e.e. for the aspirator, the difference, of course, representing the volume of water entering the aspirator from the supply pipe while the siphon is in action. The rate of inflow from the supply tank is approximately 900 c. c. per minute. The internal diameter of the long arm of the siphon is 8 mm., while that of the short arm is 25 mm. The entire length of the long arm of the siphon exceeds that of the short arm by 40 em. An apparatus of the above-mentioned dimensions will smoke four cigars of the Perfecto type, ±1 inches in length, in about thirty minutes, a rate which is probably somewhat above that of the average smoker. The pull on the cigar occurs at intervals of thirty seconds and continues for a period of ten seconds. The frequency of the pull is controlled by the rate of inflow of the water from the supply tank, while its duration is governed principally by the relation between the diameter of the small arm of the siphon and the volume of the aspirator. THE EFFECTS OF THE FILLER, THE BINDER, AND THE WRAPPER ON THE BURN OF THE CIGAR. As preliminary to the use of the cigar test in examining wrapper leaf, a series of experiments was carried out to determine the relative effects of the three components of the cigar on the burn. For this purpose a number of cigars were made by an expert w T orkman, using four different types of wrapper on each of four different types of tiller. In a portion of the cigars the binder used was taken from the same leaf as the wrapper, while in the remainder a sample of Connecti- cut Broadleaf tobacco was employed for this purpose. These cigars were smoked in the above-described apparatus under conditions as nearly uniform as could be obtained, and the evenness of the burn and the character of the ash were carefully noted. With reference to the evenness of the burn, markedly different results were obtained when wrappers taken from the same sample were smoked on different types of tiller. A typical case of this kind is shown in Plate I. The twelve cigrars shown were all made from the same 10 TESTING THE BURNING QUALITY OF CIGAR TOBACCO. sample of wrapper, and in each case the binder was taken from the same leaf as the wrapper. In the first group (A), a sample of filler grown in Texas from Cuban seed was used; in the second group (B), a heavy filler grown in Ohio from domestic seed; in the third group (C), a tiller grown in South Carolina from Cuban seed; in the fourth group (D), an imported Cuban filler. The wrapper used on these cigars was a type of Sumatra tobacco grown in Connecticut and had a very good burn. The Texas and imported Cuban fillers were known to have an excellent burn, while the South Carolina tiller was markedly inferior in this respect and the Ohio tiller intermediate in burning qualities. It will be seen that this sample of wrapper burned quite evenly when used with the imported Cuban and Texas fillers, while with the Ohio and especially the South Carolina tillers the burn was decidedly uneven. On the other hand, the effect of using different types of wrapper on the evenness of burn of any one type of tiller was less marked (see PI. 11, A, B, and C; also PI. I, D). The tiller used in this experiment was the imported Cuban, while the wrappers were taken from four differ- ent types of Sumatra tobacco grown in Connectieut. Of these four types of wrappers, that shown in Plate I, group D, had the best burn and the one shown in Plate II, group C, the poorest, although little difference could be seen between the two when smoked on the Cuban tiller. The use of different binders did not cause any marked differ- ences in the evenness of the burn, as is shown in Plate II, groups C and D. The cigars used in this experiment were all made from the same wrapper and the same tiller, while in group D a sample of Con- necticut Broadleaf tobacco was used as the binder, and in group C the binder was taken from the same leaf as the wrapper. Another important factor in determining the evenness of the burn is the proper balancing of the component parts of the cigar. It was found, for example, that a very light" wrapper will not give good results on a heavy tiller, even though both of these may in themselves possess a good burn. It will readily be seen that a very thin wrapper which burns readily and very rapidly will, when placed on a heavy, slow-burning tiller, tend to burn in advance of the latter, and the effect will generally he an uneven burn. The same result is obtained when any cigar is smoked very rapidly, for the reason that the ox} T gen of the air has freer access to the outer edges of the burning zone and under the added stimulus it rarely happens that a cigar will burn evenly. As regards the character of the ash, the wrapper and the binder are relatively of much more significance. It was found, it is true, that some tillers give an ash lacking in compactness and liable to split asunder, but the tendency to flake seems to be controlled almost entirely «The terms //';//// and heavy as used in this connection refer to the body or thick- ness of the leaf, which largely controls the rapidity of the burn. EIRE-HOLDING CAPACITY AND EVENNESS OF BURN. 11 by the character of the wrapper and binder. Furthermore, this lack of cohesion in the ash of a wrapper may be largely overcome by the use of a good binder. As to the color of the ash, a binder having a good burn will impart to the ash of the wrapper a lighter tint and a more uniform color. The general results of these experiments may be summarized as follows: (1) In order to secure a good burn, due consideration should be given to the proper balancing of the components of the cigar; that is, a heavy tiller should be wrapped with a comparatively heavy wrapper, while a light -bodied tiller requires a light-bodied wrapper. (2) Of the three components of the cigar, the tiller exerts the strongest influence on the evenness of the burn. (3) The influence of the wrapper and binder is shown most strongly on the character of the ash, and the binder very materially influences the ash of the wrapper in this respect. TESTING THE CAPACITY FOR HOLDING FIRE AND THE EVENNESS OF THE BURN. The factors of holding tire and of burning evenly are of prime importance in judging the burn of tobacco, and any sample found markedly deficient in these points may be rejected without applying any further test. As has been previously stated, the old method of measuring the lire-holding capacity is likely to lead to erroneous con- clusions, while there has heretofore been no direct method of deter- mining the evenness of the burn of wrapper leaf. In the process which we have used for testing wrapper tobacco with regard to these elements of the burn, the area of the leaf consumed, rather than the time elapsing before the glow is extinguished, is measured. The form of the apparatus used in this method will be understood by reference to the accompanying illustration (tig. 2). The essential feature is the form on which the leaf is wrapped, consisting of a col- lapsible wooden tube, one end of which tits into a glass tube of the same diameter. This latter is in turn connected with a second glass tube through which is drawn a current of air. The best material for making the wooden form is well-seasoned cherry with a straight grain, but ash has also been found to answer the purpose very well. From the wood selected is made a cylinder 5 inches in length, f inch in diameter .at one end, and tapering slightly to the other end (see tig. 3). In the larger end of the cylinder a f-inch hole is bored to a depth of 3f inches, and the shell thus formed is separated into six equal segments by saw- ing to a depth of 3i inches. The smaller end is cut down for a dis- tance of H inches, so as to tit snugly into the glass tube. The shoulder thus formed should correspond in depth to the thickness of the wall of the glass tube. Near the larger end of the form a groove (c) is cut, into which is fitted a rubber band. The plug (d) has a diameter such 12 TESTING THE BURNING QUALITY OF CIGAR TOBACCO. that when inserted in the end of the form the latter is expanded to its original size. The receiver (a) for the form is made by drawing out jr IG 2.— Apparatus for testing the burning quality of wrapper tobacco: o, entrance of air current: b, wrapper to be tested: c, e, glass tube to which the form bearing the wrapper is attached by means of the cork, to; d, d.large glass tube fitted with corl&, n, //. through which passes c, c; f, flask containing water; o, small glass lube dipping beneath the surface of the water in /; ji, short glass tube leading from/; /<. pump by means of which the current of air is secured; , , , and g,