A compound of nitrogenous matter added to the liquor to boost the action of the yeast. Yeast food.
Is added during the winemaking process to help stimulate and invigorate the wine yeast and ensure the fermentation is more active and complete.
(Fermax) Acts as a food for the yeast and promotes rapid starting and complete fermentation.
Use: 1 teaspoon per gallon of wine, or if using tablets, 1 tablet per gallon of wine.
A second wine will require that the pomace or pulp be ameliorated with water, sugar, yeast nutrients, and possibly acid and tannin, but usually not pectic enzyme. Sulfites, however, should be introduced at once to achieve and unbound sulfur level of 45-55 ppm.
Any neutral fruit juice (apple, white grape) will make a good yeast nutrient, which is generally needed in honey - which, unto itself, has no additional nutrients for the yeast to feed off of and is actually very acidic.
However, in order to reduce the risk of H2S formation, it is wise to add yeast nutrient containing diammonium phosphate (DAP) at the rate of 100-200 ppm during the early stages of fermentation.
24 lbs of crushed blackberries
13 lbs of sugar
6 quarts of fresh hot water
2 teaspoons of yeast nutrient
2 teaspoons of pectic enzyme
8 crushed campden tablets
8 quarts of fresh cold water
1 package of Narbonne wine yeast ...
Grapes are the only fruit with a high enough level of sugar and with the proper balance of acid and nutrients to sustain a natural fermentation to dryness with stable results. Other fruits or berries may be fermented, but without additions of sugar, acid, or various yeast nutrients, ...
See also: What is the meaning of Bottle, Yeast, Wine, Taste, Fermentation?