By Ray Spaziani
Wine Talk
Ray Spaziani
The use of oak plays a significant role in winemaking and can have a profound effect on the resulting wine, affecting the color, flavor, tannin profile and texture of the wine.
Oak can come into contact with wine in the form of a barrel during the fermentation or the aging process, or both.
It can be introduced into 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, which is what many of us home winemakers do. It is difficult for a home winemaker to produce wines that possess the intensity of a professional winemaker in that the use of oak barrels can impart other qualities to wine through the processes of evaporation and low levels of exposure to oxygen. Wines stored in oak are more intense in that what evaporates is water and alcohol, not wine.
The Greeks and Mesopotamians used palm wood barrels for transporting wines up and down the Tigress and Euphrates rivers, according to Greek historian Herodotus. The use of oak has been prevalent in winemaking for at least two millennia, first coming into widespread use during the Roman empire. In time, winemakers discovered that beyond just storage, wine kept in oak barrels took on properties that made the wine softer and in some cases better tasting.
Robert Mondavi is credited with expanding the knowledge of winemakers in the US about the different types of oak and barrel styles through his experiments in the 1960s and 1970s.
Oak barrels are porous and this allows a degree of oxygenation to occur. This is not the same as oxidation, which is when the wine turns brown and has a nasty burnt flavor.
An oak barrel will lose about 10 percent of the wine during a one-year period. During the course of aging this can amount to five-and-a-half to six-and-a-half gallons of wine per barrel. During the fermentation process and aging the winemaker will check the barrels and add wine to it to keep it from oxidation.
Wines can be barrel fermented in oak or they can be placed in oak after fermentation for a period of aging or maturation. Wine that is matured in oak receives more of the oak flavors and properties than wine that is fermented in oak. This is because yeast cells interact with and latch on to the oak components. When the dead yeast cells are removed from the wine as lees, some of the oak properties go with them.
A characteristic of white wines that is fermented in oak is a pale color with an extra silky texture. White wines that are fermented in steel and then matured in oak will have a darker coloring due to the heavy phenol compounds that are still present. Flavor notes that are common descriptions of wines exposed to oak include caramel, cream, smoke, spice and vanilla.
Chardonnay is a variety that has distinct flavor profiles when fermented in oak that include coconut, cinnamon and clove notes. The “toastiness” of the barrel can bring out varying degrees of mocha and toffee notes in red wines. Try some chards and red wines and see if you can determine some oak characteristics. You will be glad you did.
Ray Spaziani is the chapter director of the New Haven chapter of the American Wine Society. He is on the tasting panels of Winemaker Magazine and Amate del Vino and is a certified wine educator and award-winning home winemaker. Email Ray with your wine questions or activities at realestatepro1000@gmail.com.