The “Steps” Of Wine Making

• Grapes ripen in late August/September depending on climate. A winemaker tastes the grapes, chews the seeds, and measures the sugar content to decide when to harvest.
• Vineyard workers then quickly harvest the grapes and drop them into bins that are taken to the winery to be crushed.
• When crushed, the skin and seeds stay with red wines but are removed for white wines.
• The juice, skins, and seeds (not for white wines) are poured into stainless steel fermenting tanks.
• The winemaker usually adds cultured yeast to this grape juice. Fermentation begins when the yeast begins to digest the sugars present in the grape juice. Carbon dioxide and alcohol are by-products of this process.

Reference: http://www.winecountrygetaways.com/winemaking.html