APPENDIX B. 389 



Through various causes wines may become viscous, black, brown, cloudy, or bitter; 

 they may otherwise change essentially in color, taste, and odor. The color of red 

 wi nes may also separate in a solid form ; still all these phenomena in and of themselves 

 would not justify the condemnation of the wine as not genuine. 



If during the summer time an energetic fermentation commences in a wine, this 

 does not justify the conclusion that an addition of sugar or substances rich in sugar, 

 e. g., honey, &c., has taken place, for the first fermentation may have been hindered 

 in various ways or the wine may have had an addition of a wine rich in sugar. 



The methods adopted by the "Union of Bavarian Chemists" differ 

 considerably from the above in many particulars, so they are given also, 

 together with the methods adopted by the same body for the examination 

 of beer 1 in come v. hat condensed form. 



WINES. 



METHODS OF INVESTIGATION. 



I. Determination of specific gravity, This is to be done by means of a Westphal's 

 balance or a picnometer, and always at 15 C. 



II. Determination of extract. Ten to 50cc. wine at 15 C. are evaporated in a plati- 

 num dish on the water bath to the proper consistence and then dried in a drying oven 

 at 100 C. to constant loss of weight. Constant loss of weight is assumed when three 

 weighings, with equal intervals between the first and second and second and third 

 give equal differences between the successive weighings. 



Weighings are to be made at intervals of fifteen minutes. 



III. Inorganic matter. This is the incombustible ash obtained by burning the ex. 

 tract. Eepeated moistening, drying, and heating to redness are advisable to entirely 

 get rid of all organic constituents. 



IV. Acidity. After shaking .vigorously, to drive off carbonic acid, the wine is to be 

 titrated with an alkali solution and the acidity expressed in terms of tartaric acid. 



V. Glycerine. (1) This is determined in dry wines as follows : The alcohol is driven 

 off from lOOcc. wine, lime or magnesia added, and the mass evaporated to dryuess 

 The residue is boiled with 90 per cent, alcohol, filtered, and the filtrate evaporated to 

 dryuess. This residue is dissolved in 10-20cc. alcohol, 15-30cc. ether added, and the 

 mixture allowed to stand until it is clear. It is then decanted from the sticky pre- 

 cipitate into a glass-stoppered weighing bottle, evaporated to constautloss of weight, 

 and weighed. 



(2) The following method is employed for sweet wines : lOOcc. wine are measured 

 into a porcelain dish and evaporated on the water bath to a sirupy consistence, mixed 

 with 100-150cc. absolute alcohol, poured into a flask, ether added in the proportion of 

 1| volumes to each volume of alcohol used, the flask well shaken, and allowed to 

 stand until the liquid becomes clear. This is then poured off andlthe residue again 

 treated with a mixture of alcohol and ether. The liquids are mixed, the alcohol and 

 other driven off, the residue dissolved in water, and treated as in (1). 



(3) In all glycerine determinations it is necessary to take into consideration the 

 loss of glycerine due to its volatility with water and alcohol vapor, and accordingly 

 to add to the glycerine found 0.100 gram for each lOOcc. of liquid evaporated. 



(4) It is necessary to test the glycerine from sweet wines for sugar, and if any is 

 present it must be estimated by Soxhlet's or Kuapp's method and its weight subtracted 

 from that of the glycerine. 



VI. Alcohol. The determination must be made by distillation in glass vessels and 

 the results stated as follows : loucc. wine at 15 C. contain x grams or cubic centi- 

 meters alcohol. 



VII. Polarization. (1) The wine is decolorized with plumbic subacetate. 



1 Hi?ger, Vereinbaruugen u. s. w., p. 154. 

 4450 No. 33, pt. 3 9 



