A Step-by-Step Guide to Winemaking


Let’s take a closer look at what it takes to transform plump grapes into wine.

In late summer and fall, the grapes ripen on the vine. Winemakers continually test the sugar levels in the fruit to time their harvest correctly. Once the bunches hit their mark, teams of workers — and sometimes volunteers — race to pick the grapes before they over-ripen, rot, or get picked off by hungry critters.

After harvest, grapes are dumped or funneled into a de-stemmer — the stems contain an excess of tannins — and then a crusher. Ever seen someone stomp grapes? Well, these machines do a much better job. The result is a vat of juice and skins.

Primary Fermentation
Red wines undergo primary fermentation while in contact with their skins, which provides color and tannins; rosés typically maintain “skin contact” for a shorter amount of time. When it comes to white wines, the process is a little different: The fruit is pressed, separating the juice from the skins before fermentation. During this essential stage and the next, yeast converts sugars into alcohol, turning grape juice into wine. The initial fermentation generally takes three to five days and is done with the liquid open to the air.

Secondary Fermentation
The subsequent round of fermentation takes longer — generally two to three weeks — and is anaerobic (done with minimal exposure to air). At this point, the juice that will become red wine has taken on some of the beautiful color from the now discarded skins.

Most wines spend some time in either steel tanks or oak barrels before being bottled. For white wines, that can be as little as three to six months; for red wines, 12 to 36 months in barrels is more typical. Aging helps make the flavors in wine more complex, whether that be through malolactic fermentation (which is a process that imparts “buttery” notes often associated with Chardonnay), or absorbing traits from the wood, including vanilla and smoke. Time in oak barrels also helps smooth out the tannins in red wines.

After fermentation and aging, the finished wine is put into bottles. At wineries, this process often begins in February with the white wines. Though unfiltered wines are growing in popularity, most commercial vintages are filtered before they reach their final destination. High-tech membranes catch yeast and bacteria, leading to a more stable and predictable final product. Then the bottle — which has been sterilized with steam — is filled using a vacuum filler and closed, either with a natural cork, a synthetic cork, or a screw top. All of this can happen on one machine called a “monoblock,” on a series of specialized machines, or even by hand. The final step is attaching the label and capsule (that plastic or foil sleeve on the neck of a wine bottle).

Drink It
Now the wine is ready to be shipped, sold, and sipped. While some red wines might benefit from a few more months or years in the bottle — ask someone at the tasting room for guidance — with many Pennsylvania wines, the fresher the better. Cheers!

For more on what happens in the vineyard, check out The Lifecycle of a Grape.