The Influence of Oak Chips on Aromatic Quality of Wine

Courtesy of The Academic Wino

The use of oak chips in wine fermentation is a popular practice that has pleasing results on the flavor, complexity, quality and aroma of wine.  Oak transfers many volatile and phenolic compounds into the wine, which contributes to the wine’s complexity.  The use of oak barrels for aging also adds an additional level of complexity due to the porous nature of the barrel; whereby oxygen is able to slowly infiltrate the wine, which results in a reduction in astringency, stabilization of color, and reduction in certain aromatic characteristics.

Even though fermenting in oak barrels is favoured among many wineries it presents its own set of limitations such as the financial constraints (oak barrels are more expensive than stainless steel tanks and have to be purchased on a relatively frequent basis) and space limitations. Due to these constraints the use less expensive oak chips have become a chosen alternative. Oak chips are added to wine fermenting in stainless steel tanks, and have been found to impart similar characteristics into the finished wine as an oak barrel.

Numerous factors influence which volatile compounds and how much of each compound are extracted from oak into wine, including (but not limited to) the length of time the wine is in contact with the oak, the geographic origin of the wood, the wood seasoning, and the toasting of the wood. The varietal blend can also have a major influence on the volatile extraction of the oak wood.  Volatiles most commonly extracted from oak wood that have a significant impact on wine aroma, flavor, and quality are: lactones, volatile phenols, and phenolic aldehydes.

In regards to the specific volatiles from oak that influence wine aroma and flavor, the following are most commonly found:

  • Furfurals (dried fruits)
  • Guaiacol (burnt tones)
  • Whisky lactone (woody and coconut)
  • Eugenol (cloves, smoke, spice)
  • 4-ethylphenol (barnyard, bandaid, mousy – Brettanomyces)
  • 4-ethylguaiacol (cloves, smoke, spice, etc)
  • Vanillin (vanilla tones)
  • Syringaldehyde (vanilla)

The goal of the study presented in this article is to examine the differences (if any) in volatile aromatic compounds of wine after using oak chips from different origins and under different toasting conditions.