Working wine grapes in cellar

Working wine grapes in cellar

We asked RTD Vines & Wines columnist Jack Berninger to harvest some grape information for thirsty (or simply curious) Virginians. Here, he counts the steps.

Winemaking process

Once the growing season has ended, winemakers turn their grapes into a drinkable potion – and most follow a consistent path.

Harvesting: Winemakers and vineyard managers oversee the cutting of grape clusters from their vines by hand or machine. Hand harvesting is labor-intensive but preferred: The skins of the grapes are rarely broken, which would allow juice to seep out. 

Crushing: After leaves and debris are removed from grapes (on a sorting table or conveyor belt), they head to a crusher/destemmer. The grapes are thrown against a perforated cylinder, which gently breaks the skin and separates the stems. Juice and pulp – called must – flows into a container.

Pressing: A wine press then extracts remaining juice from the must and separates skins and seeds. For white wine grapes, the skins and seeds are discarded – but for red grapes, the skins will add color and tannin later in the process. As for the juice, it is destined for a settling tank. 

Fermenting: Yeast is added to the must in the tanks, which essentially starts the five- to 14-day process of converting sugar to alcohol. The total (or almost total) conversion of sugar results in a dry wine. Occasionally, sugar is added back to add a bit of sweetness. (For sweet wines, the fermentation process is stopped before all of the sugar is converted.) Fermenting whites is usually done at 50 to 65 degrees in temperature-controlled tanks; reds at 75 to 85.

Red alert: Because carbon dioxide is produced during fermentation of red wine, grape skins continually rise to the top of the tank during fermentation and form a cap. Using a paddle and hose, the winemaker will “punch down” or “pump over” the wine numerous times each day. This helps ensure good color, aroma and flavor. 

Clarifying: To avoid leftover particles in wine – such as dead yeast cells, excess proteins or harsh tannins – winemakers often use a process called fining or clarification: An agent, such as egg whites or clay, is added to act as a magnet to these unwanted bodies. It bonds with them and drops to the bottom of the tank or barrel, thus clarifying the wine, which is extracted without disturbing the particles.

Aging: In this final step, white wines are the sprinters, and reds are the marathoners. Whites typically are aged seven to 14 months before bottling – usually in stainless steel, sometimes lightly in oak, or a combination. Reds can spend one to two years (or longer) in barrel. Oak – be it French, Hungarian or even Virginian; new or used; toasted or not – usually is the choice for reds. 

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