Ever Wonder? Why Are Some Wines Produced in Concrete?

You may have noticed that making wine in concrete tanks seems like something new or a current fashion, but the practice actually dates back to the ceramic amphorae of ancient Greek and Roman times.

Typically, wines are fermented and aged in either stainless steel tanks and/or oak barrels.

Stainless steel tanks are the choice when a winemaker wants a ‘neutral’ vessel that does not react or impart their own flavors to the wine. But, what the stainless steel tanks don’t offer is the aspect of breathing the air, allowing air in and out of the container and having it interact with the wine over time.

Oak barrels are porous, allowing some small amount of oxygen into them and, in newer barrels, impart flavor to the wine.

What winemakers have found in concrete is that it is a semi-porous substance and allows for oxygenation like oak, it is a neutral material that does not impart flavor and it is a natural insulator that stabilizes the temperature of the wine during fermentation and aging. This allows winemakers to produce wines that tend to preserve the bright and fruit-forward flavors while still allowing for the important process of allowing the wine to ‘breathe’ during production.

Turns out the ancient Greeks and Romans were way ahead of their times by using ceramic vessels to produce wine. So, if you see a wine that was produced in concrete tanks, give it a try and see what you think. Cheers!

Fermentation Vessels Can Affect the Flavors of a Wine

In a recent blog, I listed some of the many factors that can affect a wine’s flavors. One of the factors is the type of vessel chosen by the winemaker to ferment the wine. So, let’s take a closer look.

The three most common fermentation vessels are made of either oak, stainless steel or concrete. Each of these can affect the flavor of the wine due to the degree to which the wine is exposed to oxygen.

Fermentation in Oak 
Oak fermentation barrels allow for the gradual influx of oxygen which helps to softened tannins and acid while developing a ‘rounder’ more balanced wine. Oak itself also imparts flavors. French oak is known to yield more subtle flavors like clove and spice to a wine while creating a silkier, smoother mouthfeel, while American oak typically imparts aromas of vanilla and coconut. And, the degree to which these flavors are imparted varies by the level of ‘toast’ created on the barrel during its production. So, for instance, a barrel with a ‘medium’ toast will impart less flavors than a barrel with a heavy toast. Finally, once an oak barrel has been used three to four times, the majority of the flavors have been extracted and it becomes a ‘neutral’ barrel that imparts little to no flavors.

Fermentation in Stainless Steel

Unlike oak, stainless steel fermentation vessels can be tightly sealed so as to allow little to no oxygen exposure of the wine during the fermentation process. And, a winemaker may fill the top of the tank (the headspace) with inert gas to drive out all of the oxygen. This makes for brighter, fresher fruit-forward wines. The stainless steel imparts no flavor characteristics to the wine. Stainless steel tanks are also used because they offer optimal refrigeration capabilities when a winemaker wants to cold-ferment the wine.

Fermentation in Concrete

Concrete-type vessels have been used to ferment wine for as long as wine has been made. Concrete tanks can be open for oxygen exposure, or sealed like stainless steel to avoid oxygen. The concrete itself is quite neutral so it doesn’t impart significant flavors like oak, but it can add mineral-like flavors to the wine.