Saturday
September 7, 2024 
Oak is one of a winemaker’s most important tools.
It usually takes the form of a barrel in which wines are aged. That process imbues particularly desirable characteristics to the wine, including aromas and flavors like vanilla, clove, and smokiness. It also smooths out wine’s natural astringency by very slowly allowing oxygen to penetrate the barrel through the seemingly airtight, but in fact porous, wood.
Oak also enhances a wine’s structure. Structure is the term describing the balance of a wine’s many components. The primary components being the levels of fruit, sugar, alcohol, acidity and, especially for red wines, tannin.
Malolactic fermentation also happens in the barrel. This process yields a slightly buttery taste and a creamy, velvety texture to wine. Simply explained, “malo,” as it’s known, happens when friendly bacteria consume the grape’s natural malic acid and produce two waste products; lactic acid (yes, like in milk) and carbon dioxide, which escapes into the air. Most red wines, plus Chardonnay and Viognier, usually undergo malo in barrel.
Not surprisingly, the creation of barrels (“cooperage”) has many variables that affect the final product we drink. The barrel’s size, grain, the source of the oak, and whether the oak is new or used is key. “Toasting” is also critical. Once a barrel is finished and shipped from the cooperage, the winery may literally light a fire inside the barrel to “toast” it to varying degrees, creating many new, additional flavors.
The best oak trees for wine barrels in Europe are from France, Hungary and Croatia. The USA also produces world-class oak for coopers. Our American oak has a looser grain than its Euro cousins and imparts very robust flavors, which may or may not be what the winemaker is seeking. A new oak barrel costs a winery anywhere from $600 to $2,000. And they’re generally only used two or three times, then sold to the whisky industry.
There is a significant disadvantage to using oak barrels. A mature oak tree provides enough wood to make only about two barrels (or 50 cases of wine.) Careful farming of oak trees, along with using oak alternatives (chestnut, acacia, and other, less desirable regions for oak), are important ways to respect our oak forests and our ecology in general.
Oak barrels also make a winery’s cellars look very cool. And on a more ethereal level, after a wine is aged and removed from the barrel, there are always a few ounces missing … this is the “angel’s share.”
Erno Valtri of Buckingham is a sculptor, painter, graphic designer, and a former member of the PLCB’s Wine Advisory Council. Please contact Erno at ObjectDesign@verizon.net.
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