388 FOOD AND FOOD ADULTERANTS. 



The estimation or rather the means of detecting the most of these substances has 

 already been given above with the exception of the aromas and ethers, for which no 

 method can as yet be recommended. 



The following substances may be mentioned here in particular, which serve for in- 

 creasing the sugar, extract, and free acid : Dried fruit, tamarinds, St. John's bread, 

 dates, figs. 



B. Rules for judging of the purity of wine. 



I. (aj Tests and determinations which are, as a rule, to be performed in judging 

 of the purity of wines : Extract, alcohol, sugar, free acids as a whole, free tartaric 

 acid qualitative, sulphuric acid, total ash, polarization, gum, foreign coloring mat- 

 ters in red wines, (b) Tests and determinations which are also to be carried out 

 under special circumstances : Specific gravity, volatile acids, bitartate of potash, and 

 free tartaric acid quantitative, succinic acid, malic acid, citric acid, salicylic acid, 

 sulphurons acid, tannin, manuite, special ash constituents, nitrogen. 



The Commission considers ifc desirable, in giving the estimations generally per- 

 formed, to adhere to the order of succession given above (under (a) ). 



II. The Commission cannot regard it as their province to give a guide' for judging 

 of the purity of wine, but thinks it advisable, in the light of its experience, to call at- 

 tention to the following points : 



Wines which are made wholly from pure grape juice very seldom contain a less 

 quantity of extract than 1.5 grams in lOOcc. wine. If wines poorer in extract occur 

 they should be condemned, unless it can be proven that natural wines of the same 

 district and vintage occur with a similar low content of extract. 



After subtracting the "fixed acids" the remaining extract (extractrest) in pure 

 wines, according to previous experience, amounts to at least 1.1 grams in lOOcc., and 

 after subtracting the " free acids," at least 1.0 gram. Wines which show less extract- 

 rest are to be condemned, in case it cannot be shown that natural wines of the same 

 district and vintage contain as small an extractrest. 



A wine which contains appreciably more ash than 10 per cent, of its extract con- 

 tent must contain, correspondingly, more extract than would otherwise be accepted as 

 a minimum limit. In natural wines the r elation of ash to extract approaches very 

 closely 1 to 10 parts by weight. Still a considerable deviation from this relation does 

 not entirely justify the conclusion that the wine is adulterated. 



The amount of free tartaric acid in pure wines, according to previous experience, 

 does not exceed one-sixth of the entire " fixed acids." 



The relation between alcohol and glycerine can vary in pure wines between 100 parts 

 by weight of alcohol to 7 parts by weight of glycerine ; and 100 parts by weight 

 of alcohol to 14 parts by weight of glycerine. In case of wines showing a different 

 glycerine relation an addition of alcohol or glycerine can be inferred. 



As sometimes during its handling in cellars small quantities of alcohol (at-most 1 

 per cent, by volume) may find their way into wine this fact must be borne in mind 

 in judging of its purity. 



These proportions are not always applicable to sweet wines. 



For the individual ash constituents no generally applicable limits can be given. 

 The opinion that the better kinds of wine always contain more phosphoric acid than 

 others is unfounded. 



Wines that contain less than 0.14 gram of mineral matter in lOOcc. are to be con- 

 demned, if it cannot be shown that natural wines of the same kind and the same 

 vintage, which have been subjected to like treatment, have an equally small content 

 of mineral matter. 



Wines which contain more than 0.0f> gram of salt in lOOcc. are to be condemned. 



\Vinen that contain more than 0.0'J2 gram sulphuric acid (SO 3 ) corresponding to 

 II. '211 grams potassic sulphate (K S SO 4 ) in lOOcc., are to be designated :t.s wines contain- 

 ing too Hindi sulphuric acid, either from the use of gypsum or in sonic other way. 



