Wines and Oak Barrel Flavor

Oak Barrels Why And How It Enhances WineSeveral of the better flavored wines are aged and/or fermented in oak barrels. These barrels may be new, old, small or large, or some combination thereof. The oak barrel flavor will come alive in the smaller or new barrels and in wines that spend a long time in the barrel. Another important factor is the source of the wood. Barrels are constructed when wood is cut into narrow and long pieces known as staves. These staves are seasoned and then heated so that they can be molded into the barrel shape. The cheapest method is to steam the staves. However, the most ideal method is to expose the staves to a flame. Wood that is exposed to flames for a long time becomes more toasted and charred and this significantly affects the wine’s flavor. The production of barrels is considered as both an art and a science.  Wine making is a very intriguing process and the various species of oak do play a role in wine making.

Oak’s Composition and the Oak Barrel Flavor

People tend to think that the tannins in wine come from the stems, pits and skins of the grapes. However, some tannin is derived from the oak barrels where the wines are aged. Tannins are vital to aging process and consist of an estimated 8% of French oak mass and 1% of American oak mass. Heat sensitive and hydrolysable tannins are stored in a tree’s radial rays and the toasting times, seasoning regimes, toasting temperatures and bending techniques control these tannins. Thankfully, advances in science have made it possible to achieve precise levels of oak tannin.

Lignin –> Vanillin

A group of compounds, particularly vanillin, is released while the oak lignin is breaking down. Over time, different elements in the atmosphere, including fungi, ultraviolet rays and precipitation, cause the lignin to break down and toasting speeds up this process. Therefore, with scientific study, these processes provide for more precise flavors.


Although cellulose makes up some 50% of white oak, it only plays a small role in aging wine. However, cellulose is important because it keeps the wood together.

Hemicellulose –> Wood Sugars/Body

Air seasoning starts the breakdown of a polymer into simple sugars. During toasting, as the oak is heated to 300 F, more simple sugars are formed and sweet-associated aromas and caramelized sugars begin to develop. Toasty characteristics begin to develop as the heat increases to 420 F.

This research reflects that the oak barrel flavor is defined and can be repeated through controlling temperatures.

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  1. […] size of the oak aging barrels has an impact on the ultimate wine flavor.  The ration of the barrel’s surface area and the volume of the wine will dictate on the […]