The Timeless Tradition of Oak Cooperage in Winemaking
Oak has been used in winemaking for thousands of years. It’s a durable water- and rot-resistant wood with an impressive elasticity that lends ease to construction and helps prevent damage—when moving barrels, for instance, bumping into something won’t crack or split the staves. The barrel shape can be rolled and maneuvered more easily than straight-sided cylinders or boxes, and are stackable on both the flat side (called the head) and, provided the placement is secure, along the curve.
The Oak Influence on Red Wine
Oak is the perfect material in which to age red wine. The wood’s own tannin melds with the tannin from the wine (which comes from grape skins and seeds), stabilizing color and boosting mouthfeel and structure. The toast level and intensity of charring determines what other yummy baking notes are imparted. These can be flavors like cinnamon, vanilla, nutmeg, caramel, and coffee.
Oak cooperage is not air tight, and allows for a very slow infiltration of oxygen. This oxygenation softens the wine and lessens astringency over time. When we talk about how a wine can taste and smell young or old, this softening is what we are referring to: there is a loosening of structure that happens over time, as if instead of each flavor and fragrance molecule being bound together in a tight ball they release and relax so we can pick out specific characteristics. It becomes more accessible and open, we can taste from the front of the pallet all the way through to the lingering finish.
The Angel’s Share and Evaporation
While the selective membrane of the oak allows oxygen in, it also lets wine out. One of the reasons people say a winery smells so good is because of what we call the angel’s share, which is the wine that has evaporated out of the barrels over time. The volume of loss is affected by ambient temperature and humidity, and under the conditions in our winery ends up around 9 liters of wine per barrel per year—that’s a whole case! This must be replaced periodically through topping (as in, topping up the barrels), so there isn’t too much vacant space in the barrel for too long, as this can lead to spoilage.
Merry Cellars’ Oak Cooperage Program
Oak vessels come in different sizes. The most typical, and what we have at MC, is called a Bordeaux or barrique, and holds 225 liters (60 gallons). Slightly larger are Burgundy barrels, at 228 liters, and Cognac at 300. Getting into the larger formats, puncheons hold 500 and demi-muids 600 liters. There are gigantic casks which the French call foudres and the Italians botti that can store up to 30,000 liters of wine!
The Merry Cellars oak cooperage program heavily features neutral oak. This means we use them repeatedly and that while the oxygenation aspect of aging still occurs, there is assumed to be no flavor or tannin characteristics being imparted upon the wine any longer. A good rule of thumb is to think of each year as using up half the impact a barrel has to give: the second year a barrel is used it only has 50 percent of its original power; the third year 25 percent; the fourth 12.5; and on and on until the remaining influence of the barrel on flavor is negligible. We have barrels still in use which first debuted in 2005, and our newest ones are from 2019.
Explore the barrel room next time you’re in the tasting room and take a whiff of that delicious angel’s share. Cheers, friends!
—Maureen
