In the northern hemisphere, grape harvest takes place between August and November.
By machine: In many cases, the grapes are mechanically harvested by a machine. Mechanical harvest is common for large vineyards on flat land.
By hand: In some cases, grapes are harvested by hand. This can be the case for vineyards grown on slopes or land that machines cannot access, and for premium wines that require careful grape selection.
In the winery, grapes are crushed to released the juice. Traditionally, the crushing took place by “food treaders,” where people gently stomped on the grapes to release the juice. But today, this is most commonly done by machine.
After grapes are crushed, the juice is placed into fermentation tanks, vessels or barrels.
Black grapes are commonly fermented with the grape skins in the juice to release color, flavor and texture.
White grapes are usually fermented without their skins to remain clear and fresh.
Wild (ambient) yeast exist naturally on grape skins, stems, and even in the winery itself. A winemaker can choose to use these naturally-present yeasts to complete the fermentation process, or add yeast to the juice (most common). The grape juice temperature must be adjusted to the right setting in order for yeast to begin and continue their job.
Over the course of several weeks, the yeasts consume the grape juice sugar and replace it with Carbon Dioxide and Ethanol (alcohol). Once the yeasts consume all the sugar, they die and are filtered out of the wine. However, if the winemaker were to remove the yeasts before all the sugars were consumed, the wine would remain sweet with lower levels of alcohol.
In many cases, the wine is quickly bottled, and sent to market for immediate consumption.
Other wines undergo aging before they are bottled. This could be to soften the grape tannins, integrate the flavors, and improve over time. Aging wine in new oak barrels will also impart sweet and spicy notes into the wine and allow oxygen flowing into the barrel to create even more flavors.
The longer a wine is stored in a winery, the higher the final cost of the bottle.
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