Oak has been an indispensible tool in wine making, from barrels, staves, and oak chips to oak essence used in wine fermented in stainless steel tanks. The use of oak in wine has the ability to change the entire profile of the wine allowing the precious contents of the oak barrels to develop a better flavor, aroma, and body.

It is no surprise that the most expensive wines in the world, From the Chateau Lafite 1865 to the Screaming Eagle Cabernet Sauvignon 1992, use Oak to age their wines in some way.

Effects of Oak Aging

Aging wine in Oak has four unique impacts on the wine making process that help develop the wines body, aroma, and flavor:

 Evaporation:

Aging wine in oak allows it to evaporate and lose some of its water and alcohol and concentrates the flavor and aromas of the wine. Additionally, this forces winemakers to “top-up” or refill the barrels with more wine from the same vintage further increasing the flavor and aroma of the wine. This is also a primary reason why aged wine has a higher price tag as compared to wine with a shorter aging process.

Oxygenation:

When first opening a bottle of red wine you are always told to let the wine “breath” which is a term for introducing oxygen into the wine to allow it to soften and lose some of its astringency. During the aging process, oxygen allows the wine to mature but too much oxygen will turn any fine wine into lack luster alcoholic grape juice.

Oak barrels have much smaller grains then other traditional wood that are turned into barrels allowing small amounts of oxygen to enter which helps the wine mature. Wine can still mature without the oxygen but it will take more time to achieve the same results as wine that was allowed to age with some oxygen.

Phenol:

Phenols are compounds that can be found in grapes and the wood that bind together to create different flavors. Oak contains a phenolic compound called Vanillin, which tastes like Vanilla. So putting wine in oak is like putting vanilla extract into Cakes and cookies. Adding a little will  help enhance the other flavors already present in the wine and adding more will impart the flavor into the wine. The phenols also bind together to create bouquets and aromas of honey, caramel, and mocha among other flavors present in both red and white wines.

Tannins:

Oak barrels give wine more tannin and when using younger oak barrels it give oak flavor to the wine. Tannins give you the color and the dry mouth feel that are normally found in Cabernet Sauvignon, Petite Sirah, and Nebbiolo. Tannins also allow the wine to age better and smoothen out as the wine ages.

Types of Oak

There are 2 main geographical locations for the sourcing of Oak for wine making. Oak can come from America normally farmed in eastern and central North America and Europe primarily from France but with some sources in Eastern Europe as well.

 European Oak

European Oak can be classified as French or Eastern European. The most expensive and sought after Oak barrels for wine making are French oak but Hungarian/Eastern European Oak are from the same species making them suitable alternatives to the much pricier French barrels.

French Oak will generally have a smaller grain then it’s American brother giving a more tame and subtle oak flavor. The size of the grain determines how much oxygen can enter the barrel, as well as, how much of the wine comes into contact with the oak and the amount of flavor that the oak imparts onto the wine.

 American Oak

American White Oak generally have much larger grains which increases the amount of wine that penetrates the wood and the amount of oxygen that can enter and leave the barrel allowing the wine to extract more Oak flavor and tannins from the barrel.

Written by Carlo Locsin