Oak (wine)
The Greek historian Herodotus noted that ancient Mesopotamians used barrels made of palm wood to transport wine along the Euphrates.
In time, winemakers discovered that beyond just storage convenience, wine kept in oak barrels took on properties that improved it by making it softer and, in some cases, better-tasting.
[3] The porous nature of an oak barrel allows evaporation and oxygenation to occur in wine but typically not at levels that would cause oxidation or spoilage.
Phenols within the wood interact to produce vanilla type flavors and can give the impression of tea notes or sweetness.
White wines fermented in steel and matured in oak will have a darker coloring due to heavy phenolic compounds still present.
[6] Flavor notes commonly used to describe wines exposed to oak include caramel, cream, smoke, spice and vanilla.
Chardonnay is a varietal with very distinct flavor profiles when fermented in oak, which include coconut, cinnamon and cloves notes.
The butter flavors come from lactic acid, naturally present in the wine, converted during malolactic fermentation to diacetyl.
High end Rioja producers will sometimes age their wines up to ten years in American oak to get a desired earthy cedar and herbal character.
[9] Italian winemakers have had a long history of using Slavonian oak from the Quercus robur which is known for its tight grain, low aromatics and medium level tannins.
[10] Prior to the Russian Revolution, Quercus petraea oak from Hungary was the most highly sought after wood for French winemaking.
The trees in the Hungarian Zemplén Mountains grow more slowly and smaller in the volcanic soil, creating fine tight grain which sequentially lends itself to a very delicate extraction.
However, after the fall of the Iron Curtain, the cooperages from France again became major consumers of the exclusive Quercus petraea/Sessile Hungarian Oak trees originating in the Zemplén Mountain Forest.
[7] Winemakers choose American oak typically for bold, powerful reds, base wines for "assemblage", or for warm climate Chardonnays.
[11] Open air seasoning has the advantage of leaching undesirable chemical components and bitter tannins, mellowing the oak in a manner that kiln-dry methods are incapable of replicating.
Its more pronounced oxidation and a quicker release of aromas help wines to lose their astringency and harshness more quickly, which makes this the wood of choice for shorter maturations - six to ten months.
French oak, on the other hand, generates silky and transparent tannins, which transmit a sensation of light sweetness combined with fruity flavors that persist in the mouth.
The cost of barrels varies due to the supply and demand market economy and can change with different features that a cooperage may offer.
[17] The staves are then heated, traditionally over an open fire, and, when pliable, are bent into the desired shape of the barrel and held together with iron rings.
The toasting also enhances the presences of vanillin and the phenol eugenol which creates smokey and spicy notes that in some wines are similar to the aromatics of oil of cloves.
[20] In 1999, the Bordeaux court of appeals fined four wineries, including third growth Chateau Giscours, over $13,000 USD for the use of oak chips in their wine.
[21] Throughout history other wood types, including chestnut, pine, redwood, and black locust, have been used in crafting winemaking vessels, particularly large fermentation vats.
[22] Chestnut is very high in tannins and is too porous as a storage barrel and must be coated with paraffin to prevent excessive wine loss through evaporation.
In Chile there are traditions for using barrels made of rauli wood but it is beginning to fall out of favor due to the musky scent it imparts on wine.
