How yeast nutrient helps

TO obtain the best possible fermentation the yeast, like most living organisms, must have both food and oxygen. Like human beings, it needs both vitamins and fresh air! The ideal medium for fermentation is pure grape juice, which contains all the nutrients, or foods, that the yeast requires, but some of the liquors we ferment for country wines (notably mead and all—the flower wines) are deficient in them, and it is therefore wise to add a nutrient to give the yeast a "boost," the nitrogenous matter mentioned previously.

You can obtain several good proprietary yeast nutrients from trade sources, but if you wish to have your own made up by your chemist a good formula, similar to that of the British Bee Keepers' Association, is:—

Ammonium Sulphate

60 grains

Magnesium Sulphate

8 grains

Citric Acid

130 grains

Potassium Phosphate

30 grains

This is for a gallon of mead: halve the quantities for one gallon of wine.

Buy it, ready-made up, from your chemist, thoroughly mix the chemicals by shaking vigorously in a small quantity of water in a medicine bottle, and add to the brew at the same time as the yeast.

If you cannot obtain even this nutrient, on no account omit some acid, which is the most important single ingredient; when making up your must, or pulp for fermentation, include the juice of a lemon, or H oz. of citric acid. If there is no acid at all in the ingredients, about % oz. citric acid per gallon of must should be added.

If, on the other hand, the recipe you are using already includes lemon juice or citric acid, omit that in the nutrient or the wine may be over-acid. The addition of nutrient will enable the yeast to carry the fermentation just that little further, a great help in the production of strong, dry wines, and in the avoidance of oversweet wines. Failing all else, use 1 dessertspoonful of malt extract per gallon.

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