If you read the wine press, or even those little tags with scores and reviews that some stores put up, you will come across discussions of “oak” and “new oak”. So what does oak have to do with wine?
For millennia many wines have been aged in wood casks, now usually made of oak or chestnut. In the twentieth century it became common to age wines in other containers such as stainless steel and lined cement. There is nothing wrong with these techniques, but wood does have an impact on the wine. Even the tightest wood casks are somewhat porous. The down side to this is you lose some wine to evaporation. The upside is that over time you get very small amounts of oxygen entering the wine. While large amounts of oxygen are detrimental to wine when it ages, these small amounts are good. It allows the small amounts of yeast still living in the wine after fermentation to continue to live. This has a stabilizing effect on the wine.
Any wood cask will allow for what is called micro-oxidation. Oak does more. There are chemicals present in oak that flavor wine. Smaller containers have more oak to the volume of wine and thus give more of the flavors. Smaller barrels called barriques are used when significant impact from oak is wanted. The amount of flavor a barrel can add to wine diminishes with use. Most wineries will not use an oak barrel for flavor more than three times. Thus you will see discussions of “new oak”. This just means the barrels are being used for the first time. Wine geeks will even get into talking about what kind of oak tree was used with “American oak” adding stronger flavors than “French oak”. Oak from Slovenia is also used. It is considered to be somewhat neutral.
So what does oak taste like? Well exploring Chardonnays is a good way to find out. Most California and Australian Chardonnays are aged in wood, most frequently American oak. They also typically have spent some time in new oak. If you taste a white Burgundy such as a Macon, Meursault, or the like, you are probably tasting French oak. Different makers age their wines for different amounts of time and for different amounts of time in different age barrels but you can still quickly pick up the change that oak makes. Finally, taste a good Chablis aged in stainless steel. This is Chardonnay without any oak. I like them all but if you have a preference, knowing what oak does can help you find wines you like. Enjoy.