Fermentation Vessels: Why Do They Matter?

Category: Drink

Winemaking is both an art and a science. While there are many fundamental processes that need to be followed when making a wine of any kind, there is also an opportunity for expression by the winemaker, and there are many decisions that he or she can make to mold and shape the wine into a certain style.

Image via @hobowinecompany

Different methods within the winemaking process affect the way the wine will turn out.

For example, if said winemaker would like to make a fresh, clean, easy-drinking Sauvignon Blanc, he might choose to: pick the grapes when they’ve achieved ripeness, immediately press the grapes and separate the juice, put the wine through a cold fermentation in stainless steel, and bottle early. He’s not likely to use native yeast, or age in oak, and a lot of oxygen exposure will be avoided.

One of the most important decisions that a winemaker needs to make is what type of vessel the wine should live in during fermentation. These days, the three most popular fermentation vessels are made of oak, concrete, and stainless steel. Theses materials affect the makeup of the wine differently because they allow varying amounts of oxygen to be exposed to the wine within. Let’s take a look at how they differ:

Oak allows for the gradual influx of oxygen, which will result in softened tannins and acid, and a rounder wine. French oak tends to give more subtle nuances like clove and spice to a wine and create a silkier texture, while American oak imparts more overt aromas of vanilla and coconut. Lastly, the level of toast on a barrel will also affect the flavors in the wine. A barrel with a medium toast will impart less charry and smoky characters than a barrel with a heavy toast.

Image via @hobowinecompany

Stainless Steel 
Wines fermented in stainless steel vessels are usually made in a more reductive (or rather, non-oxidative) fashion. The tank remains closed up when not being used, and inert gas is used to fill any headspace in the tank and displace oxygen. This makes for cleaner, fresher wines that are great for early drinking. The stainless steel material imparts no distinct flavor characteristics on the wine. Stainless steel tanks are very ideal for ferments that need to say bone-chilling cold, because they offer optimal refrigeration capabilities.

Image via @hobowinecompany

Concrete tanks have been used to ferment wine for as long as wine has been made. People stopped talking about them for a while, when the stainless steel hype arrived. Now, they’re quite cool again, and some winemakers have taken it to another level with egg-shaped concrete fermenters that promote the flow and movement of fermentation. Sometimes concrete tanks are large, square or rectangular shaped and open, while other times they are locked up just like stainless steel to avoid oxygen. The concrete itself is quite neutral, though it can leave a mineral-like aspect to the wine’s sensory profile.

Image via @gmcfarla

Creativity is key. Some producers will put half of a batch in oak and throw the other in an egg, or ferment in stainless steel and age in oak. Regardless, these vessels are responsible for nurturing our wines in their early stages, and in the case of oak… keeping them cozy for a while until they’re ready to make their debut!

About the Author
Katie Delaney is a winemaker by trade, Advanced Sommelier, oenophile and founder of The Rebel Wine Collective. She’s seen the wine industry from two very different sides of the spectrum - one of which involves stilettos, and the other steel-toed boots - but the wealth of knowledge that Enology and Viticulture have to offer is what she loves most about the world of wine. Katie spends her days working with, teaching, and learning from wine fanatics.