have a darker coloring due to heavy phenolic compounds still present. 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 "toastiness" of the barrel can bring out varying degrees of mocha and toffee notes in red wine. It is a common misconception that oak imparts butter flavors to wine. The butter flavors come from lactic acid, naturally present in the wine, converted during malolactic fermentation to diacetyl. This process reverses itself, although the addition of sulfur dioxide prevents this, and the diacetyl remains. Wines can be barrel fermented in oak or placed in oak after fermentation for a period of aging or maturation. Wine matured in oak receives more oak flavors and properties than wine fermented in oak because yeast cells present in fermentation interact with and "latch on" to oak components. When dead yeast cells are removed as lees some oak properties go with them. The length of time a wine spends in the barrel is dependent on the varietal and finished style the winemaker desires. The majority of oak flavoring is imparted in the first few months the wine is in contact with oak, while longer term exposure adds light barrel aeration, which helps precipitate phenolic compounds and quickens the aging process. New World Pinot noir may spend less than a year in oak. Premium Cabernet Sauvignon may spend two years. The very tannic Nebbiolo grape may spend four or more years in oak. 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. Oak types and sources The species of oak typically used for American oak production is the Quercus alba which is a white oak species that is characterized by its relatively fast growth, wider grains and lower wood tannins. It is found in most of the Eastern United States as well as Missouri, Minnesota and Wisconsin where many wine barrels are from. In Oregon the Quercus garryana white oak has started to gain usage due to its closer similarities to European oak. In France, both the Quercus robur (common oak) and Quercus petraea (white oak) are considered apt for wine making; however, the latter is considered far superior for its finer