Yeast

or Barn, is the froth or scum which rises on beer during the act of ferment a« tion. See BARM. Yeast is an article of the greatest unportance in domestic economy; forming a nece ary ingredient in bread, which would otherwise become heavy and unwholesoine. As it cannot at all times be obtained in sufficient quantities, we propose to state various methods which have been contrived for generating and preserving this commodity, In the 2d vol. of the Memoirs of the Phi logo phi cal and Literary Society of Manchester, Mr. Henry has published a method of preparing artificial yeast, by which goo! bread may be made, without the aid of any other ferment. He directs flour and water to be boiled to the consistence of treacle; and, when the mixture is cold, to satutate it with fixed air. Next, if must be poured into large bottles with narrow mouths, which should be loosely covered witht paper; and, over this, with a slate, and a weight to keep them; teady. The bottles ought now to be placed in a room, the temperature of which is from 70 to 80°; and the mixture be stirred two or three times in the course of 24 hours. At the end of about two days, according to Mr. H. such a degree of fermentation will have enstied, that the mixture acquires the consistence of yeast. In this state, the flour intended to be made into bread must be incorporated with such artificial barm, in the roportion of 6 lbs. of the foftier to one quart of the latter, and a due quantity of warm water. The whole is now to be kneaded together in a proper ve el, covered with a cloth, and suffers ed to stand for i2 hours, or till i be sufficiently loaves, and baked. Mr. Henry. adds, that this yeast would be more perfect if a decoetion of malt were substituted for water. ‘A. simple decoction of malt, however, now fully proved to be convertible into yeast, fit for brewing: this discovery was‘ made by Mr. Joseph Senyor, on whom the Society for the Encouragement of Arts, in the year 1790, conferred a bounty of 20/. He directs three wooden or earthen ve els to be procured, one being capable.of holding two quarts, the other three or four, and the third five or six quarts. A quarter of a peck of malt is then to be boiled for eight or ten minutes, in three pints of water; when one quart must be poured off the grains into the first ve el: as soon as the liquor becomes cool, such’ ve el ought to he removed towards the fire, or toa temperature of about 70 or 80° of Fahrenheit’s thermometer. the course of 30 hours the fermentation will commence; when two quarts of a similar cool decoction (made, we suppose, from the same malt) must be mixed with this yeast, in the second, or larger ve el; and be repeatedly stirred in the manner practised in common vats. As the fermentation increases a greater portion of the like decoction must be added, and be worked in the largest ve el: thus, at length, a sufficient quantity of yeast will be produced for brewing 40 gallons of beer. This useful contrivance of Mr. Senyor is farther confirmed by the recent experiments of a correspondent, whose plain and interesting account we are induced to quote in his own words: ‘* I caused (says he) a gallon of rather weak wort to be made; with part of which, when cool, I filled the middle part of Nooth’s machine: as soon as it was thoroughly saturated with fixed air, I mixed the whole and placed it in a wooden ve el near the fire, the weather being rather cool. In about 24 hours there were some faint signs of fermentation; yet, at the expiration of the fourth day, I obtained no more than two table-spoonfals of very indifferent yeast; and the wort had become extremely offensive. As the yeast was not only very poor, but in too small a quantity for any domestic purpose, I made an infusion of alt: and a decoction of hops, in the manner used among the inhabitants of the island of Jersey, when they find it nece ary to increase a small quantity of brewer's yeast. ‘To this oa beet I added my two spoonfuls of yeast; et the mixture stand 24 hours; then poured off the watery part; mixed the sediment with an increased proportion of the malt and hops; which fermented, and produced yeast enough to work a gallon of strong beer, that yielded a pint of very fine yeast, of which excellent bread was made. Having some reason to suspect that the fixed air was of little or no use in this experiment, and that a wort might’ be made which would ferment of itself, before the liquor were spoiled by too long keeping, I caused to be made four gallons of good wort, rather above porter strength, well hopped, and with a considerable quantity of colour, and was equally’ divided, one-half impregnated with fixed air, as in the first experiment; each was put into a wooden ve el; and both were placed in an equally warm situation. At the expiraticn of 24 hours, there being no signs of fermentation, I stirred in a tea-spoonful of salt, and shook a little flour on the surface of each. In 12 hours more, the unimpregnated wort shewed some appearance of fermentation, which went off, and was renewed by placing the liquor near the fire; and at the 74th hour it had a tolerably good head of yeasty but the impregnated wort was only beginning to ferment. In 24 hours after, we took a pint of yeast from the wort which was not impregnated with fixed air, and about a tea-cupful from the other, which was as inferior in quality as in quantity. The worts were then mixed, put into other ve els, and bid fair to become excellent beer.—I cannot say that this is. a_very expeditious mode of making yeast; but I believe it is a sure one, and within the power of every person who can procure the nece ary. ingredients for making good beer.”—Our correspondent, therefore, conceives to have proved by this experiment, that fixed air is, at least, not requisite to produce a fermentation in beer. Dr. Lettsom (Hints for promoting Beneficence, . 1797) recommends the following preparation as a substitute for yeast: boil 4 oz. of flour in two quarts of waiter, for half an hour; and sweeten it with 30z of Muscovade sugar. When the mixture is nearly cold, pour it on four spoonfuls of yeast, into an earthen or stone jar sufficiently deep to admit the new barm to rise: it must now be well shaken; placed near the fire for one day; and then the thin liquor be poured off the surface. The remainder is next to be agitated, strained, closed use, and kept in cool place. Some of the yeast thus prepared ought always to be preserved, for renewing or making the next quantity that may be wanted. The following method of preparing excellent yeast we state from the Transactions of the Economical ‘Society of Peters burgh, on the authority of baron Von Mestmacher: when the wort is made, and it becomes nece ary to provide yeast for its fermentation, he directs 40 gallons to be drawn off into a ve el provided with a lid, and capable of holding one-third more than that quantity. Next, 7lbs of leaven are to be di olved in a little wort, and mixed with the 40 gallons: 17 lbs. of ryemeal, and an equal quantity of ground malt, must now be added, by agitation for some minutes, and suffered to stand for half an hour. At the end of that time, a spoonfal of the best yeast ought to be incorporated with this compound; the lid be placed upon the ve el; and the whole remain undisturbed for 48 hours; when the mixture will be found converted into 60 gallons of remarkable good barm. n the Ist vol. of Annals of Agriculture, Mr. Kirby suggests mealy potatoes to be boiled till they become perfectly soft; in which state they must be mashed with hot water, so as to acquire the consistence of yeast. ‘Two ounces of coarse sugar, or mola es, are then to be added to every pound of potatoes; and, when the mixture is luke-warm, two spoonfuls of barm must be stirred into it, according to the pro- portion above stated, This composition should now be removed towards the fire, or toa warm place, till the fermentation cease; when a certain portion may be kneaded with flour, which ought to stand eight hours before it is baked.—Mr, K. observes, that every pound of potatoes thus managed produces nearly a quart of yeast, which will remain good for three months,—The roots, however, ought, in the opinion of Mr. Bordley, to be perfectly ripe and well-sprouted; as tn the contrary case no fermentation will ensue. ‘Similar to this preparation is the substitute for yeast contrived by Mr. Richard Tillyer Blunt; in consequence of which he obtained - a patent, in October, 1737.—He directs g lbs. of potatoes to be boiled in water, in the same manner as for the table: after which they must be mashed; and, while they are warm, 20z. of honey, or other saccharine matter, and one quart of common yeast, should be at hive pints of this compound are suf- ficient, with the aid of warm water, for making the sponge; and, when this begins to sink, the dough ought to be formed into Joaves and baked. An useful substitute for yeast may be cb- tained by nearly filliag a bason or tea-cup with bruised or split pease, and pouring on them boiling water: the whole is now to be get on the hearth, or other warm place, for 24 or 48 hours, according to the temperature of the season: at the end of that time, a froth, po e ing all the properties of yeast, will appear on the surface of the Guid. This method, we understand, is commonly practised in the gastern countries; and the bar in thus rocured is said to render the bread light and vohatable, To the different modes of procuring yeast already specified we shall add an easy and ex- ‘peditious proce , which appears to be very plausible; and has lately been communicated ‘to the editor by an anonymous correspondent; though he cannot vouch for its succe . —Take six quarts of soft water, and two handfuls of wheaten or barley-meal; stir the latter in, before the mixture is placed over the fire, _ where it must very gradually simmer, and at length boil, till two-thirds of the fluid be eva- orated, so that it may consist of two quarts. Vhen this decoction becomes cool, incorporate with it (by means of a whisk) a powder “consisting of two drachm is of salt of tartar, and ‘one drachm of cream of tartar, previously ‘mixed. The whole should now be kept ina warm place.—Thus, a very strong yeast for brewing, distilling, and baking, is said to be obtained. For the last mentioned purpose, ‘however, such barm ought to be first diluted ‘with pure water, and pa ed through a sieve, before it be kneaded with the dough; in order to deprive it of its alkaline taste. _ The preservation of yeast, for a considerable time, is an object of equal importance to that of producing it artificially: hence, it has been Tecommended to put a quantity of that com- modity into a canvas bag, and to submit the whole to the action of a screw-pre , sO as to deprive it of all moisture; in consequence of which, the barm will remain in the bag, as firm and tough as clay: in this state it must be packed in casks, well secured from the acce of air, and may be kept in a sound state for any period of time. We believe, however, it would be more safe and advisable to form the pasty yeast into circular, flat ve els, ree sembling tea-saucers, and in that state to dry the whcle ma , either in the open air under shade, or in the moderate warmth of a baker's oven. Mr. Felton Mathew’s mode of separating beer from yeast, and preserving the latter (for which he obtained a patent, in February, 1796), in many respects corresponds with that just described: the nbadtpil difference that he directs the bags to be placed in troughs perforated with holes, ‘to prevent the former from bursting; and then to submit them to the action of a lever, aided by incumbent weights, When the beer is thus expre ed, the yeast remaining in the bags will crumble into coarse powder: this must be spread on canvas, hair-cloth, or similar porous material, and gradually dried in a malt-kiln, or in any room or stove, where a regular temperature of from 80 to gO degrees is maintained; and, lastly, as soon as it becomes perfectly dry, the barm must be packed in bottles or casks, from a which the air is completely excluded, Another mode of preserving yeast consists in throwing a withy, or the young shoots of willows twisted together, mzo the ve el where the yeast is working; and suspending them in a warm room till the next opportunity of brew ing arrives. We conceive, however,. the following expedient to be preferable, both in point of cleanline and economy; it being succe fully practised by some careful housewives:—-Lake a clean wooden bowl, of such size as may be most convenient; spread a regular coating of yeast around its inner surface; and, as often as this dries, repeat the proce , till a thick cake be formed: the ve el must be kept in a dry place, When any barm is wanted, a small piece may be cut out; and after di olving it in warm water, the solution will answer all the purposes. of fresh yeast, whether designed for baking or for brew- Migs The following proce being advantageously employed in Germany, for preserving barm, so as to be fit for all domestic uses, after a considerable time, we have inserted it for the benefit of our country readers: When the yeast is taken from new beer, it must be put into a clean linen bag, and be laid in a ve el half full of dry sifted wood-ashes: the whole is then to be covered to the thickne of three or four inches with similar ashes, and be pre ed together. In this situation the barm should fernain for a day, or longer, if it be nece ary 5 when the ashes will absorb all the moisture, and the yeast acquire the consistence of a thick aste. Jt must now be formed into ‘small fain $5) or balls; dried in a moderate heat; and kept in bags, in an airy, dry place: when any barm is wanted, a few of such balls may be di olved in warm water; or, which is preferable, in beer; and they will answer every purpose of fermentation. Besides its utility in baking and brewing, late experiments have fully proved, that yeast is of - singular efficacy in putrid fevers, putrid sore throats, and similar malignant complaints: for the first discoverv of this important fact we are indebted ‘to the Rev. Edmund Cartwright. ‘The dose of barm, according to his experience, and that of other practitioners, is two large spoonfuls, to be repeated every threé hours; in some cases this has been sufficient 5 but, in others, it was nece ary to administer the Peruvian’ bark, between each dose.< In a few instances, indeed, emetics and laxatives were given previously to taking the yeast; but, in general, this simple remedy seldom failed to effect a cure; provided due attention was bestowed on the ‘diet and regimen of the patient. eae Yeast consists of gluten, sugar, and mucilage, with some alcohol, and a portion of malic, acetic, and carbonic acids; but the e ential parts of yeast are gluten mixed with a vegetable acid, and therefore dried yeast, which must have lost some of its component parts, is fit for fermentation equally with that which is fresh and new. hae 396 397 398