Read on for a basic explanation of what oak means in relation to wine!
There is a strong affinity between wine and oak. Oak is a watertight hardwood. It has long been recognized as a very suitable vessel for both fermenting and storing wine. As well as imparting the various aromas and flavors that we associate with an oaked wine such as vanilla, spice, smoke, clove etc., it also works behind the scenes, in the sense that it helps to naturally clarify and stabilize wines.
Types of Oak: Provenance, Toast, New vs. Old and Size
The species of oak that is suited to wine is white oak, of which the two most important and used types are French Oak and American Oak. American oak tends to impart a more obvious vanilla, sweet spice note to wine. However, it is not as simple as just that.
A second factor is the 'toast level's the oak, which can be high, medium or light. The higher the toast level the stronger the aromatic and flavor influence on the wine.
A third influencing factor on the wine is whether the oak is new or used. New oak imparts the strongest influence. Second pass, third pass and older barrels impart little to negligible flavor to a wine. Producers use older barrels for structural and textural reasons rather than flavor influencers.
A final factor to consider is the size of the barrel. Wine fermented and/or matured in small barrels known as 'barriques', will have more oak influence than a wine in a larger oak cask.
Wine producers spend a lot of time each year working out the 'ideal' oak regime for their wine. It usually involves a complex combination of different types of oak, different toast levels, different barrel sizes, different coopers and a careful mix of new and old.
Oak Fermentation and Oak Maturation
We more often see the words "barrel fermented" on white wines rather than red. The term barrel fermented usually refers to a wine being fermented in small barrique-sized oak barrels (60 US gallons / 225 liters). It is difficult and messy to barrel ferment red wines in barrique (though some do it), because you have all the skins and seeds debris to deal with and remove from the barrel's small bung hole! You do not have this problem with white wines as they are fermented off the skins. Oak fermenters for red wine are significantly larger in size (5,000 gallons)
As well as the aroma and flavor influence imparted based on the factors of provenance, age, toast and size of the oak barrel, fermenting wine in barrel enhances the texture and structure of the wine, and you have less overt primary fruit aromas.
Most red wines and many white wines spend some maturation time in oak after fermentation and before bottling. Oak maturation, helps create additional complexities in the wine, as the compounds in the wine interact with the compounds of the oak. In red wines, oak maturation helps fix color and soften tannins.
Oak Barrels Are Expensive! Enter the Barrel Alternative: Chips and Staves
Oak barrels are expensive, far too expensive to justify using when making a high volume wine that will retail for under $10. Enter the barrel alternative. Barrel alternatives come in the form of staves or chips. Staves are oak planks that are attached to the insides of stainless steel tanks, to emulate some of the flavor and mouth feel influence of a barrel. Oak chips, which are smaller pieces of oak, are usually added to the juice before fermentation. As with barrels, oak chips and staves come in all sorts of permutations and combinations in terms of toast level and provenance.
Oak Influence: Balance is Key
The use of oak when making wine is supposed to have an enhancing influence, not an overpowering one, masking the fruit. Balance and integration are key, which is why winemakers spend so much time working out the perfect oak regime for each wine in each vintage.
Mary Gorman-McAdams, MW (Master of Wine), is a New York based wine educator, freelance writer and consultant.
Previous Wine Words
• Wine Words: Style
• Wine Words: Sweetness
• Wine Words: Length and Finish
• Wine Words: Minerality
• Wine Words: Acidity
• Wine Words: Tannin
• Wine Words: Body
• Wine Words: Alcohol
• Wine Words: Aromas
• Wine Words: Texture
• Wine Words: Complexity
(Image: Underlying image by Sadovnikova Olga/Shutterstock)