Oak character in wine can be difficult to recognize, but often resembles freshly sawn wood, vanilla and butterscotch.

Symbol for oak character is vanilla. One symbol means minor oak character, two symbols medium oak character and three symbols mean distinct oak character.

Minor oak character

Medium oak character

Distinct oak character

Oak can come into contact with wine in the form of a barrel during the fermentation or aging periods. The use of oak imparts to the wine pleasant aromas and longer shelf life. More about oak in wine making can be found below and under the tab Wine Components and wine lesson Barrel aging.

More about Oak

The use of oak plays a significant role in winemaking and can have a profound effect on the resulting wine, affecting the colour, flavour, tannin profile and texture of the wine. Many wines are matured in oak barrels, and some are even fermented in oak.

Oak is porous and allows small amounts of oxygen to pass into the wine, a process called microoxidation. It is this process that is the secret behind the oak influence on the wine. The oxygen is namely catalyst for a variety of chemical processes.

One effect is that he colour of the wine is intensified by the oak tannins.

Another important effect is that of the natural tannins become softer. This is done through a so-called polymerization, a chemical reaction in which small molecules clump together and form a chain. The chain eventually becomes so large and heavy that it falls to the bottom of the barrel. The result is a less harsh wine.  

Oak can come into contact with wine in the form of a barrel during the fermentation or aging periods. It can also be introduced to the wine in the form of free-floating oak chips or as wood staves (or sticks) added to wine in a fermentation vessel like stainless steel.

Oak from different sources will impart different characteristics on the wine, but in general oak maturation gives aromas of butter, toffee, caramel, vanilla, spice and butterscotch.

French oak may give more buttery aromas, whereas American oak gives stronger vanilla and spice aromas, but there are many more variables in the equation than this simple statement suggests.

It all depends on how much oak is used, how much of it is new as opposed to re-used, how long the wine stays in contact with the wood, whether the wine is merely aged in oak or whether the fermentation takes place in it, how the oak has been treated, and so on. For instance, barrels that have been “toasted”, which means the cooper has formed them around a small fire, often burning the oak shavings he has produced in the manufacturing process, will have aromas of smoke and toast. Barrels that have been steamed during manufacture, however, may give more oatmeal aromas.

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