4 THE ANALYEIT. THE ANALYSIS AND COMPOSITION OF ENGLISH BEERS. BY T. A. POOLEY, B.Sc., F.C.S. THE complete analysis of so complex a fluid aB beer is attended with considerable difficulty, and the methods at our disposal are by no means so perfeot M we might desire ; it is, however, a, subject of considerable importanae, and it is therefore surprising that so few analyses have been published. Our text-books give the compositions of several kinds of foreign beer, but the analyses of English beers have been few and far between, and relate principally to the determination of two or three of the principal constituents, such as the alcohol, extract, and ash.Believing that a comparative examination of various beers brewed in different parts of the kingdom under various systems and with a variety of materials would be interesting, I have lately occupied myself in performing such a series of analyses, and in this and some succeeding papere, it, is purposed to lay the results obtained before the readers, TheTHE ANALYST.6 object in view was to ascertain the exact proportions of all the more important constituents in the typical descriptions of beer brewed in this country, in order that a comparison may be made as to their respective values as foods and wholesome stimulants.Adulterants have not been especially sought for, as they are rarely, if ever, added by brewers, but the results may be of some value to brewers, who may, by com- paring the analyses of beers taken direct from the brewery with those taken from retailers, be able to ascertain whether their products are offered to the public in the state of purity they ought to be.These investigations have been undertaken in no prying spirit, but simply to ascertain the exact composition of many varieties of beer ; the results will naturally lead to certain deductions as to the nature of the materials used in the manufacture of each kind of beer, for that is one of the objects of the investigation, and it will be of considerable interest to trace the influenceof the mineral oonstituents of certain brewing waters on the chemical composition of the resulting beers.This subject was taken up some time since by Mr, C. Estcourt, of Manchester, who read a paper upon the desirability of fixing some standards of value for beer, before the Society of Public Analysts at their meeting at Dublin last year,':' but I cannot find that his investigations have been proceeded with ; his results are, however, interesting, and I shall have occasion to refer to them again.Some analysis of Burton Ales and Dublin Porter were also made last year by Messrs. Lawrence and Reilly, and their results were communicated to the Royal Irish Academy.In the analyses which will be given in these papers, it is proposed to take a wider field, and to examine the products of many breweries in different parts of the country; for this purpose I have already either been supplied with, or promised, samples by many brewers, and I trust to the kindness of others in assisting me in the same way. No analysis of any sample of beer obtained from a brewery will be published without the consent of the proprietor, and the analyses of samples obtained from retail establishments will be described in the same way as they were bought.To enter into a detailed and elaborate description of the processes employed in the analyses would be somewhat out of place in these pages. No claim is made to any originality of method, for as a rule, the best methods as laid down by well-known authorities on chemical analysis, have been closely followed, but when the exigency of the occasion require it, a modification has been introduced.The determinations usually made have been as follows :-Specific gravity-Original gravity-Carbonic acid- Alcohol-Extract-Acetic acid-Glucose-Dextrine-Lactic acid-Ash, including silica, ime, phosphoric acid and chloride of sodium-Nitrogen, and the corresponding quantity of albumenoid bodies, The methods at our disposal do not enable us to determine with anything like precision the quantities of hop extract, resin and oil, or such substances as tannic acid, glycerine, and fatty bodies, and, therefore, except in a few particular instances these determinations have not been attempted.I will now describe in as short a manner as possible the general method of analysis employed, leaving to future papers some special remarks on the various precautions which have to be taken to ensure correct results, Spec@ Gravity.-This has always been determined by the specific gravity bottle, * THE ANALYST, vol. iii., p. 325.6 THE ANALYST.and not by the saccharometer, as the last-named instrument scarcely gives sufficiently accurate results when great precision is required, on account of the impossibility of preventing the bubbles of carbonic acid gas from adhering to the bulb and stem of the instrument. The most convenient sized bottle is one holding 1,000 grains of pure distilled water at 60° F., which before use must be carefully cleaned and dried ; although not absolutely necessary, it is convenient to have a weight which is the exact counter- poise of the bottle when empty ; then by simply filling the bottle with the beer to be tested and weighing it, the specific gravity is ascertained.The bottle should be provided with a small stopper having a capillary tube through i t ; in this way great exactness of quantity can be ensured.It is of course of the utmost importance to take the specific gravities of different samples of beer at precisely the same temperature, and for this purpose 60° F. is the most usual standard, and the one I have always adopted. The specific gravity of English beers varies considerably between 1,003 and 1,012, but 1,012 is about the average. Original Gravity.-This is the term employed to indicate the strength of the wort from which the beer was made, and is determined by the method which is now familim to most brewers ; it consists in distilling a known volume of the beer until at least one- half has distilled over, and then diluting both distillate and residue with distilled water to the same volume as that of the beer used ; the specific gravity of each is then taken, and by reference to tables compiled for the purpose, the percentage of alcohol and extract can be ascertained; we are acquainted with the exact amount of malt extract necessary to produce a given quantity of alcohol, and therefore by adding this to the extract left after distillation, we arrive at the total extract originally present in the wort before fermentation.A correction has to be made for any acetic acid contained in the beer, but in sound sardples this correction is very insignificant. Great care must be taken in observing temperatures, as the specific gravity of a fluid varies considerably with every alteration of temperature; 60° F. is the usual standard; and all the determinations of specific gravity referred to in these papers have been made at this temperature.The specific gravities have been taken by means of the bottle and not by the saccharometer, and the weighings have been made on a balance of very delicate construction. An error in taking the specific gravity of beer is liable to arise in con- sequence of the presence of excess of carbonic acid, and therefore it is as well always to make the determinations in the beer after it has been well shaken to remove the excess of gas.Carbonic Acid.-This is a gaseous coustituent which ought always to be present in beer, as the pleasant fresh taste of this beverage is due to this gas. The quantity varies very considerably ; in bottled beer it is usually present in excess, but in cask beer the quantity is much smaller, and in some cases, where great flatness prevails, almost absent.The determination of carbonic acid is of interest under some circumstances, but as the proportion alters so rapidly when beer is exposed to the atmosphere, these determinations have but little value for the purpose of comparing one sample with another. In making an analysis of beer, it is well to previously remove any excess of carbonic acid gas by shaking the beer in a stoppered bottle until no further pressure is exerted on the stopper; in this way dl the gas is not removed, but different beers areTHE ANALYST.7 brought to the same standard as far as relates to their gaseous contents, and the results then obtained have some value for comparison.I n the aiialyses that will be given in future papers, all beers will have been thus treated, except in some cases of which special mention will be made. In case the determination of carbonic acid is necessary, the following method may be employed. A known qnantity of beer, say 100 cubic centimetres is placed in a good sized glass flask connected by means of a cork and bent tube with a vessel containing a, quantity of a solution of hydrate of baryta. This vessel must be carefully protected from the atmosphere in order that no carbonic acid is absorbed from that source.Upon heat being applied to the flask, the gas is gradually expelled, and having to bubble through the baryta water is all absorbed, with the formation of carbonate of baryta, which, being insoluble in water, separates in the form of a white powder.After all the gas has been expelled, this precipitate is filtered off and washed thoroughly, and is weighed in a platinum crucible with the usual precautions ; 197 parts of carbonate of baryta are equal to 44 parts of carbonic acid gas, and therefore by a simple calculation it is easy to ascertain the quantity of gas present in the 100 cubic centimetres of beer employed in the experiment.Great care must be taken that the gas is not given off too rapidly, otherwise some of it may escape absorption in the baryta water, and in filtering off the precipitate rapidity is important, otherwise there may be absorption from the atmos- phere, As it is impossible on the present occasion to find space for the remainder of the description of the method of analysis employed, I will conclude with giving the results obtained with one sample of beer.Analysis of sample of 4d. beer obtained from a publichouse in Messrs. Truman, Hanbury & Co.’s trade :- Specific gravity of beer .................................. 1012.16 9, 1 7 .. distillate .............................. 992.45 .. residual extract ........................ 1019.75 Original gravity of beer .................................. 1050.97 =18.36 lbs.per barrel. Alcohol ...................................................... 4.200 per cent. Total extract* ................................................ 4.810 .. Acetic acid .................................................. -034 .. Carbonic acid ................................................ *138 ..Water by difference ........................................... .90*824 .. 100*000 per cent. *Total extract contains the following constituents :- Glucose ...................................................... 1.390 per cent. Dextrine .................................................... 2.060 ,, Lactic acid .................................................. ,058 ,, ........................ I .................................. Phosphoric acid -046 Ash containing Lime ~603 -476 Chloride of sodium ...................... -115 Nitrogen.. ............................................ ,029 Extractive matters of the hop, fatty bodies, glycerine, &c., by t equal to dbuminous substances.. .............................. *204 ?, difference ................................................ -622 ,, 4.810 per cent. In the next paper the description of the method of analysis employed will be concluded, and further examples of the results obtained will be given.-Brewers’ G,uardian.