During primary fermentation, esters are formed in excess by yeast metabolism and are responsible for “fruity” and “floral” aromas. Acetates are synthesized at higher concentrations than ethyl esters, and the ratio between both, as well as the concentration at which acetates are produced, is affected particularly by:
- fermentation temperature
- must nutrient content
- yeast strain
When secondary or malolactic fermentation (MLF) is carried out on Chardonnay to transform malic acid to lactic acid, this also produces diacetyl and acetoin which contributes the typical “buttery”, “hazelnut”, and “fresh bread” notes.
Next up, Aging Derived Compounds.
Note November 3, 2017: The illustration that was initially on this post has been updated to correct spelling errors. It has also been organized according to chemical class.
References:
1. Gambetta JM, Bastian SEP, Cozzolino D and Jeffery DW., Factors influencing the aroma composition of Chardonnay wines, 2014, J Agric Food Chem 62:6512–6534.
Illustration created from Table 3. Characteristics of Odorants Important to Chardonnay Wine Typicity Formed during Alcoholic and Malolactic Fermentation, pg. 6514-6515 of the reference above.
2. Joanna M. Gambetta, Leigh M. Schmidtke, Jiaming Wang, Daniel Cozzolino, Susan E.P. Bastian, David W. Jeffery, Relating Expert Quality Ratings of Australian Chardonnay Wines to Volatile Composition and Production Method American Journal of Enology and Viticulture Jan 2017, 68 (1) 39-48; DOI: 10.5344/ajev.2016.16058
No comments:
Post a Comment