Updated: Jul 30, 2021
Oak ageing wines is a process that allows a winemaker to impart color, texture, aroma, and flavor to the fermented juice. There are several varieties employed in wine production and the variance can be subtle to extreme. I frequently tell people to imagine putting a volume of water into an oak barrel. Gradually, the water will take on a yellow or even brown color as it remains in contact with the inside of the wooden vessel. If you were to drink the water that had been aged in an oak barrel, which I discourage, you could anticipate a grainy texture in that water, extracted from the barrel. Oak barrels have varying aromatics as well, like a box of cigars, sweet cedar and tobacco notes, fresh dill, pine, leather, sawdust, toast and chestnut are among many aromatics that an oak barrel can infuse into the wine. Oak has flavor. Not to suggest that wood chips wood be a pleasant amuse bouche, but in the production of many wines the flavor of the barrel integrates with the flavor of the juice to offer a harmonious balance. French Oak, American Oak, Slovenian Oak each offer unique aromatics, flavors, textures, and colors. Beechwood, and Chestnut are frequently employed as well with alternative results.
We can see the effect of long term oak ageing easily but differently, in white and red wines. In fact, when blind tasting, looking at the wine often tells me a great deal of the story of its production process. I can determine what it might be, and what it cannot be based on the knowledge of whether it was aged in a barrel. White wines aged in oak have pronounced straw to brown color hues, one can ascertain the variety, pedigree, and duration of ageing often simply by sight. New barrels are expensive, and the impact of their use is aggressive, so the barrels are reused often. Each subsequent use of a barrel changes the extraction ratio of color, texture, aroma, and flavor. Many winemakers use new oak, or used barrels based on desired results for the specific wine style they are creating. Looking at a red wine, the oak age can often be noticed in a browning of the wines color. Juice that may have been a vibrant purple color after fermentation shows less bright, and more brown, and frequently one can speculate the duration of oak ageing based on the degree of color pooling in the glass.
The decision to age a wine in oak is an expensive endeavor, and many wines, especially whites, do not require or even respond positively to oak ageing. Wines engineered to offer bright acidity, floral aromatics, and fruity flavors need not be obscured by oak manipulation. A definitive experiment to see the effect of oak is to try a Sauvignon Blanc, perhaps from New Zealand, side by side with a Fume’ Blanc. This will show the aromatics of Sauvignon Blanc in a compare and contrast based primarily on the decision to gently oak the juice in the Fume’ Blanc. Chardonnay also allows for the opportunity to easily see unoaked vs oak style side by side. Using these styles of wine is a great study guide to see the effect of base oak manipulation. With practice one can learn the subtle differences of oak styles, and new vs neutral barrels.