Winemaking Terms - Yeast Starter to Zymase

Yeast Starter:

 

A media in which a wine yeast is activated and encouraged to multiply to a high density so that when added to a must it will have a better chance of populating it successfully. There are several ways to make a starter. To make a really vigorous starter for inoculating a must initially or restarting a stuck fermentation, in a quart jar dissolve 1 teaspoon of sugar and 1/8 teaspoon of yeast nutrient in 1 cup of warm water (less than 104° F.). To this, add 1/4 cup of the juice from the must to be fermented. Sprinkle 1 packet of active dry yeast on the surface of the liquid. Do not stir. Cover the jar with a paper towel or napkin held in place with a rubber band. Wait for the yeast to become active. This could become obvious in as little as 15 minutes or could take as long as 2-4 hours. If no evidence of activation in 4 hours, the yeast was too old or dead from exposure to temperature extremes (usually heat, but possibly extreme cold). In such a case, sprinkle another packet of yeast into same jar and recover. When yeast (first or second sachet) is evidently active, add another 1/4 cup of juice from the must and recover. Wait until vigorous activity returns (usually 30-90 minutes) and add another 1/4 cup of juice. When again vigorously active, add yet another 1/4 cup of juice. Wait 1-2 hours and gently pour half the liquid over the surface of the must. Do not stir. The idea is for the starter to remain on or close to the surface where there is plenty of air for the yeast to "breath." Cover the primary fermentation vessel with a sanitized cloth or sheet of plastic. After 2-4 hours, the surface of the must should have small bubbles rising from fermentation or a healthy layer of yeast culture. Stir shallowly and recover the primary. Wait another 2-4 hours and fermentation should be more vigorous. Add the remainder of the starter and stir deeply. Recover primary. If the starter does not produce a vigorous fermentation in the primary, add another 1/4 cup of juice to the reserved half of the starter media. Wait 2 hours and add yet another 1/4 cup of juice. This starter is now 2 parts juice and 1 part water. When this is fermenting vigorously, add half of it to the must as before and try again.

 

Zest:

 

While "zest" is a quality a good, fresh wine might possess, when mentioned as an ingredient in the recipes on this site, zest refers to the grated rind of lemon, orange, grapefruit, or lime. Only the colored portion of the rind is used, as the white pith is bitter and will spoil the batch. When a recipe calls for 2 lemons, both the zest and the extracted juice are intended unless otherwise stipulated.

 

Zymase:

 

The name given to the group of enzymes which yeast use to transform sugar into alcohol.

Source: Jack Keller

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