What’s the difference between wood vs. steel vs. concrete wine fermentors?
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Dear Dr. Vinny,
What’s the difference between wood vs. steel vs. concrete fermentation vessels?
—Eddie, Aspen., Colo.
Dear Eddie,
There are many variables for each type of fermentation vessel that can modify their effects, but here is a straightforward look at the basics, with some helpful links if you want to take a deeper dive ….
Wood barrels are typically made from oak, but can also be made from chestnut, acacia or other trees. Barrels allow a very small amount of oxygen to interact with the liquid inside (micro-oxygenation) and can impart additional tannins, which impact the wine's structure. If the barrel is new or only a few years old, it can also introduce flavors and aromas such as toast, cedar, spice, vanilla or even chocolate. Older or “neutral” barrels will have a more muted effect. Barrels can also be quite expensive, costing up to $1,000 each or more, depending on size and wood source, among other factors.
Stainless steel tanks are cost effective and popular, and can be made to be impermeable to oxygen. They are durable, easy to clean and most modern tanks can be temperature-controlled. Winemakers who prefer stainless steel tanks like that they emphasize the purity of a wine’s fruit flavors, without the distractions of oak influence.
Concrete fermentors are kind of between steel and wood: They're neutral vessels, meaning they do not impart any flavor to the wine, but some winemakers believe that they can soften a wine's texture. The thick walls of concrete fermentors can also reduce temperature fluctuations as the wine ferments.
—Dr. Vinny