THE MICROBIOLOGY OP ALCOHOL PRODUCTS S3 1 



particularly subject to turning brown, owing to the large amount of 

 oxidase present in apple juice. 



The use of sulphurous acid for preliminary defecation, pure yeast in 

 the fermentation, and fining, followed by pasteurization soon after the 

 fermentation, seem to offer the best means of improving present 

 methods. 



These methods were introduced into a cider-vinegar factory in 

 California by W. V. Cruess with excellent results. 



Fermented Beverages or Various Fruits 



Many other fruits, especially those rich in sugar and with moderate 

 acidity, are used locally to produce alcohoUc beverages. The methods 

 of fermentation are similar to those used in wine making, but additions 

 of sugar and water are usuallyi made to correct defects of composition. 

 Very often distilled alcohol is also added after fermentation to preserve 

 the liquid, which is thus rendered unsuitable for an ordinary beverage. 



Hydromel or Mead 



An alcoholic beverage made by the fermentation of honey and water 

 is much used in eastern Europe. 



Honey contains from 65 to 74 per cent of reducing sugars and from 

 2 to 10 per cent of saccharose. It is diluted with water to reduce its 

 concentration to 22° Bal.*-'24° Bal. A few yeast cells are usually 

 present in the honey but these are of various kinds and often unsuit- 

 able. The use of a good pure yeast is therefore advisable. As honey 

 contains little mineral or nitrogenous yeast food, an addition of nutritive 

 substances is often necessary. 



The following formulae are recommended by Kayser and Boullanger 

 to be used in one liter: 



A. Dicalcic phosphate i g. 



Ammonia .• 2 g. 



Bitartrate of potash 2 g. 



Magnesium sulphate o. i g. 



B. Maltopeptone i ■ S g- 



Bitartrate of potash i ■ S g- 



Ammonium phosphate i . o g. 



• "Balling" refers to the degrees of the special hydrometer for determining the specific 

 gravity of saccharine solutions such as must or beer wort. Its purpose is to indicate directly 

 the percentage of solids in solution at a temperature of 6o.°F. 



