The purpose of the yeast is to convert sugars to carbon dioxide and alcohol and to impart flavor from other metabolic products. E. Step 4. This is the aging and maturing step. F. Some notes. Light beer - allow yeast to ferment more of sugars.
Wines differ from beers primarily in that the sugars are in a fermentable stage.
Beers typically fermented from grains B. Grapes. Viticulture - the grapevines are pruned and trained to a trellis. North American grapes are not suitable for wine making, although Vitis labrusca can be used. Red or green grape varieties can be used for making wine. C. Grape Harvest.