442 
Half an ounce of this gas will delay fermentation in 100 gallons 
of grape juice 10 to 12 hours. 
One ounce Metabisulphite ot Potassium yields oz. of sul- 
phurous acid fumes. When used for checking too rapid a fermen- 
tation and the invasion of injurious moulds and bacteria into 
a fermenting wine a fairly heavy dose is used, as a good deal of the 
sulphur fumes become non-effective and are driven out during the 
tumultuous fermentation. : 
To control and check rapid fermentation, 80z. of Potassium 
Metabisulphite may be used per ton of grapes. Divide into four 
packets of 20z. each. Dissolve in a bucket with hot water; mix the 
first dose with the bulk of the pulp or of juice. Take the tempera- 
ture; when it rises fairly high add the second packet; then the 
third packet. The temperature is taken every few hours. The fer- 
mentation may be longer, but accidents will be averted. Even if 
sulphiting does not prevent hot fermentations it generally averts 
some of the worst consequences of hot fermentations by discourag- 
ing the growth of injurious moulds and of bacteria. 
FERMENTATION. 
Is the process of biological transformation of substances in 
solution in a liquid into products chemically different. This trans- 
formation is generally accompanied by movements similar to boil- 
ing (L. fervere, to boil). In the case of vinous or of alcoholic fer- 
mentation, there is production of bubbles of gas and also of alcohol 
and of other products. 
The active agents of fermentation are micro-organisms which 
float inside the liquid which affords them food; they are capable 
of transforming considerable quantities of material into other 
products. 
Although wine is the result of the fermentation of the juice of 
the grape, it is only when acted upon by microscopic living organ- 
isms which have received the name of “yeasts,” that the transforma- 
tion of the sweet juice of the fruit into wine is accomplished. 
On every sweet fruit, nature has placed some kind of ferment 
capable of converting its juice into a fermented liquor. In grapes 
these ferments, known in France as “levures,” in England as 
“Yeast,” are known to botanists all the world over—for yeast is a 
plant—by the name of Saccharomyces. 
Thus, of the ferment of beer, known as 9. cerevisiae, there are 
several sub-varieties, some of which, like the ferments of “low fer- 
mentation,” are bred by the brewers of lager beer and maintained 
at a low temperature of 45 to 54deg. F. (7-12° C.), and others, the 
ferments of “high fermentation,” are to be Found in those brew- 
eries where the type is more that of Bass’s beer or Guinness’s stout. 
