Part I

I. Commercial wines may be defined as follows : (a) The product obtained by the fermentation of grape juice with or without grape skins and stems. (b) The product obtained by the fermentation of pure must, to which pure sugar, water, or infusion of grape skins has been added. It must contain not more than 9 pec cent. alcohol and 0.3 per cent, sugar, and not less than 0.7 per cent. acid,estimated as tartaric. (c) The product obtained in southern countries by the addition of alcohol to fermented or partly fermented grape juice. French wines are not included, however. (d) The product obtained by fermenting the expressed juice of more or less completely dried wine grapes.

II. The above definitions do not apply to champagnes.

III. The following include the operations undergone by wines in cellars (Keller-massige Behandlung): (a) Drawing and filling. (b) Filtration. (c) Clarification by the use of kaolin, isinglass, gelatine or albumin, with or without tannin. (d) Sulphuring. Only minute traces of sulphurous acid may be contained in wine for consumption. (e) Adulteration of wine. (/) Addition of alcohol to wine intended for export.

IV. Wines, even if plastered, must not contain more sulphuric acid than that corresponding to 2 grams potassic sulphate (K2SO4) per liter.

V. Medicinal wines are those mentioned in Parts I and IV, with the following restrictions : (a) They must not contain more sulphuric acid than corresponds to 1 gram potassic sulphate per liter. (b) They must contain no sulphurous acid. (c) The percentage of alcohol and sugar to be given on the label. (d) These restrictions apply only to wines expressly recommended or sold for medicinal use.

Part II

I. Improperly gallized wines are preparations of grape juice, pure sugar and water, or grape-skin infusion, that contain more than 9 per cent. alcohol or less than 0.7 per cent. acid, or both, and preparations in which impure glucose has been used. The following facts enable us to detect them: Small quantity of inorganic matter (phosphoric acid and magnesia), and right rotation if impure glucose is used. If the rotation exceeds 0.2° to the right, the wine is to be concentrated, freed from tartaric acid as far as possible, and again polarized.

II. Addition of alcohol is to be assumed if the ratio of alcohol to glycerine is greater than 10 to 1 by weight.

III. Addition of water and alcohol is recognized by the diminution in the quantity of inorganic matter, especially magnesia, phosphoric acid, and usually potash. Addition of water alone is recognized in the same way.

IV. Scheelization, i. e, addition of glycerine, is assumed if the ratio of glycerine to alcohol exceeds 1 to 6 by weight.

V. The presence of cane sugar is ascertained by a determination of sugar (by Soxhlet's or Knapp's method), before and after inversion.

A. Methods Of Investigation

By beer is to be understood a fermented and still fermenting drink, made from barley (or wheat) malt, hops, and water, and which was fermented by yeast.

I. Determination of specific gravity. - For this as well as all other determinations the beer is freed from carbonic acid, as far as possible, by half-filling bottles with it and shaking vigorously. It is then filtered. The specific gravity is then determined either by Westphal's balance or by a picnometer at 15° C.

II. Determination of extract. - Seventy-five cubic centimeters of beer are carefully weighed and evaporated in a suitable vessel to 25cc, care being taken to prevent boiling. After cooling, water is added until the original weight is reached, and the specific gravity of the liquid taken as in I. The per cent. of extract is obtained from this specific gravity by the use of a table constructed by Dr. Schultz, and is given as "per cent. extract, Schultz."1

1Hilger, p. 123.

III. Alcohol is determined by distilling the beer. A picnometer of about 50cc. capacity and with a graduated neck is used as a receiver. The picnometer is carefully calibrated. Seventy-five cubic centimeters of beer are distilled until the distillate reaches about the center of the scale on the neck of the picnometer. This is then cooled to 15° C, dried, and weighed, and the alcohol determined by means of Baum-ber's table.

A = D . d

g The percentage of alcohol by weight is to be given. In very acid beers it is necessary to neutralize before distilling.

IV. Original gravity of wort. - This may be ascertained, approximately, by doubling the per cent. by weight of alcohol found as above, and adding the per cent. of extract. As this procedure is not exact, it may be made more nearly so by using the formula

100 (E +2.0665 A) 100 + 1.0665 A

V. Degree of fermentation. This is estimated by using the formula

v1 = 100(1 - E/c).

VI. Sugar determination. - This is to be determined directly, in the beer previously freed from carbonic acid, by Soxhlet's method of weighing the reduced copper; 1.13 parts of copper correspond to 1 part anhydrous maltose.

VII. Determination of dextrin is seldom required, and if required is to be performed by Sachsse's method.

VIII. Nitrogen. - Twenty to thirty cubic centimeters are evaporated in a Hofmeister "schalchen" or on warm mercury, and the extract burned with soda-lime. The nitrogen may also be determined by Kjeldahl's method.

IX. Acids. - (a) Total acids: The carbonic acid is driven off from 100cc. of beer by heating in beakers for a short time to 40o C. and the beer then titrated with baryta water (one-fifth to one-tenth normal). The saturation point is reached when a drop of the liquid has no longer any action on litmus paper. The acidity is to be given in cubic centimeters normal alkali required for 100 grams beer and as grams per cent. of lactic acid. The indication "acidity" or "degree of acidity" is insufficient.

(b) Normal beer contains but a very small quantity of acetic acid. The determination of fixed acid in the repeatedly evaporated extract is to be cast aside. The acetic acid produced by souring of the beer is shown by the increase in total acids. A qualitative test of the presence of acetic acid in the distillate from beers containing acetic acid is sufficient. Neutralized beer is to be acidified with phosphoric acid and distilled. Weigert's method is recommended.

X. Ash. - Thirty to fifty cubic centimeters of beer are evaporated in a large tared platinum dish and the extract carefully burned. If the burning takes place slowly, the ash constituents do not fuse together.

XI. Phosphoric acid. - This is to be determined in the ash obtained by evaporating and burning in a muffle 50 to l00cc. of beer to which not too much baric hydrate has been added. The phosphoric acid is determined in the nitric acid solution of the ash by the molybdenum method.

XII. Sulphuric acid. - The direct determination is not permissible. The determination is to be made by using the ash prepared by burning with sodic hydrate and potassic nitrate or baric hydrate and proceeding in the ordinary way.

XIII. Chlorine. - This is to be determined in the ash prepared with sodic hydrate.

XIV. Glycerine. - Three grams calcic hydrate are added to 50cc. of beer, evaporated to a sirupy consistence, about 10 grams coarse sea-sand or marble added, and dried. The dry mass is rubbed up, put into a capsule of filter paper, placed in an extraction apparatus, and extracted for six to eight hours with 50cc. alcohol. To the light colored extract at least an equal volume of ether is added, and the solution, after standing a while, poured into or filtered into a weighed capsule. After evaporating the alcohol and ether, the residue is heated in a drying oven at 100° to 105° C. to a constant loss of weight. In beers rich in extract the ash contained in the glycerine can be weighed and subtracted. In case the glycerine contains sugar, this can be determined by Soxblet's method and subtracted.

XV. Hop substitutes are to be determined by Dragendorff's method. Picric acid is to be determined by Fleck's method. In examining for alkaloids, check experiments with pure beer must in all cases be made.

XVI. Sulphites. - One hundred cubic centimeters of beer are distilled after the addition of phosphoric acid and the distillate conducted into iodine solution. After one-third has distilled over, the iodine-colored distillate is acidified with hydrochloric acid and baric chloride added. If sulphites were not contained in the beer no precipitate is observed, but at the utmost a turbidity.

XVII. Salicylic acid. - This may be shown qualitatively by shaking with ether, chloroform, or benzine. The solution is allowed to evaporate, the residue dissolved in water, and a very dilute solution of ferric chloride added. The addition of too much acid and too violent shaking is to be avoided. The smallest trace of salicylic acid may also be shown by dialysis, as it passes very readily through membrane.

Note

All the results of an investigation are to be stated in percentages by weight.

B. - Methods of judging purity of beers.

I. It is unjust to demand in a fermented beer an exact ratio of alcohol to extract, as the brewer cannot regulate the degree of fermentation within narrow limits. As a rule, Bavarian draft and lager beers contain from 1.5 to 2 parts of extract for each part of alcohol, but a smaller proportion of extract would not necessarily prove the addition of alcohol or glucose (the former to the beer, the latter to the wort).

II. The degree of fermentation of a beer must be such that at least 48 per cent. of the original extract has undergone fermentation.

III. If glucose or other bodies poor in nitrogen have been used in appreciable quantity as substitutes for malt, the nitrogen contents of the beer extract will fall below 0.65 per cent.

IV. The acidity of a beer should not be greater than 3cc. normal alkali to 100cc. beer. Acidity of less than 1.2cc. normal alkali to l00cc. beer indicates previous neutralization. If the acids are composed principally of lactic acid a larger quantity may be present.

V. The ash of normal beer is not above 0.3 grams to 100 grams beer.

VI. The amounts of phosphoric and sulphuric acids and chlorine in beer extract vary within such wide limits that their determination signifies nothing as to the purity of the beer.

VII. The amount of glycerine in pure beer is not greater than 0.25 gram to 100 grams beer.

VIII. The following methods of clarifying beer are legal: (a) Filtration. (b) Well-boiled hazel or beech shavings. (c) Isinglass.

IX. The following methods of preserving beer are legal: (a) Carbonic acid. (b) Pasteurizing. (c) Salicylic acid, this only for beers intended for export to countries where the use of salicylic acid is not forbidden by law.

Note

The preceding methods are also to be used in the examination of imported beer.

C - Administrative note.

It is absolutely necessary that the beer be preserved in well-corked green-glass bottles. Stone jugs and such vessels are not to be used. The beer samples are to be protected from light and kept at a low temperature. Care in making tests is, above all, necessary.