How is wine made? What are the basic steps of winemaking?

Dear Dr. Vinny,

I’m a brand new manager at a very influential winery in eastern Washington. I’m hoping to create a comprehensive winery tour guide sheet for my employees so they can properly show guests around the facility. Can you explain the basics of wine production? I’m hoping not to embarrass myself when I send my rough draft back to the production crew for confirmation.

—Lauren, Richland, Wash.

Dear Lauren,

Wow, that is a huge question! There are thousands of decisions a winemaker makes throughout the winemaking process, and there’s no way to cover them all here. But I’m happy to give you some broad strokes on how winemaking works to help you with your project.

Harvest

First, grapes are picked. When to harvest is one of the most important decisions a winemaker will make each year. Too early, and the grapes won’t be ripe enough. Too late, and the grapes will be overripe—or they can be threatened by bad weather, like rain and cold, which could damage the grapes and promote disease, like rot. You might want to find out if the grapes at your winery are harvested by hand or machine, and if harvest is done at night or early in the morning when the grapes are nice and cool.

Sorting, Pressing and Fermentation

Once the grapes arrive at the winery, they will be processed. That can include sorting (by hand or machine) and an opportunity for MOG (or “matter other than grapes”) to be picked out.

White wines are made by fermenting just their juice, so the grapes are typically pressed or crushed first to isolate the juice. There are a lot of choices to be made about how hard to squish the grapes, so you should find out the protocol, including if there is any skin contact and why the winemaker made that choice. (For more details, check out our guide, “How White Wine Is Made”!)

Red wines are made by fermenting the grapes, not just the juice. They can be destemmed, kept as a whole cluster (where the grapes are still attached to the stem), crushed, or some combination thereof.

Fermentation comes next. That’s when the sugar in the grapes is converted to alcohol with the help of yeast. Winemakers can add commercial yeast or let the native yeast (that’s already on the grapes and in the air) do the work. Find out what your winemaker prefers and why.

During fermentation, there are an endless number of decisions to make. Some winemakers like long, cool fermentations, others something a little warmer. If there is a cap, is that going to be managed by punch-downs or pump-overs? What happens if there is a stuck fermentation?

To Oak or Not to Oak?

There are a multitude of fermentation vessels, and each is used for different reasons. Stainless steel is popular because it is very neutral and lets a wine’s fruit flavors shine through.

Then there are wood barrels. There are thousands of choices of barrels alone. Consider the cooper (who makes the barrel), level of toast, what forest the wood comes from, and even what kind of wood. Oak is popular, and American oak and French oak impart different characteristics, but chestnut, acacia and other woods are also used.

The barrel can be new, in which case it will impart baking spice and vanilla flavors. It can also be used, or “neutral,” in which case it shouldn’t add flavors but can help round out a wine’s texture by exposing the wine to small amounts of oxygen. Even the size of the barrel is a big decision.

There are also other fermentation containers made from concrete, porcelain, glass and other materials, and all have their attributes. A wine might come from a single vessel, or be made from a mix.

From Fermentation to Bottling

After that primary fermentation, a winemaker has to decide if their wine will go through malolactic conversion, and to what extent. Typically a wine will be racked to separate the juice from the solids that settle in winemaking. Then a wine can be aged for days to years before it’s finished, and of course the vessels used for aging are yet another decision.

If a wine is a blend of different lots, consider that a winemaker has to manage each lot separately, and then blend the components together. There might be some more aging after that process. Finally, a winemaker needs to make the call to fine, filter or cold stabilize the wine—or not! And then, at long last, the wine is bottled (typically, though not always, with the addition of sulfur dioxide). Some wines are further aged before they are ready for sale.

As you can see, the decisions involved in making wine are seemingly endless, and this is just the tip of the iceberg. Good luck with your project!

—Dr. Vinny