It’s that time of year again when this yeast can rear its ugly head. Brettanomyces can produce the volatile phenols 4-ethyl phenol (4EP) and 4-ethyl guaiacol (4EG), which are responsible for sweaty, horsey or medicinal off-flavours in wine.

Right now red wines should have completed primary fermentation and have been transferred to barrels for oak maturation. During oak storage, substrates are leached from the wood into the wine, and can provide metabolites for Brettanomyces growth.

Throughout oak maturation, winemakers should be vigilant in their control and monitoring of volatile phenol production, particularly in unfiltered wines with low molecular sulfur dioxide levels. The molecular sulphur dioxide levels should be above 0.8mg/L to ensure that your wine is protected.

We can help you manage these compounds in a number of ways including monitoring the 4EP & 4EG in the wine, analysis of molecular sulphur levels, by conducting microbial analysis on your wine to determine the viability of Brettanomyces yeast or by using the molecular biology technique, PCR, to determine the presence of viable Brettanomyces yeast.

Vintessential can also offer our Wine Fault Solutions kit which can be used to spike wine to train your cellar staff in the olfactory assessment and identification of wine faults including Brettanomyces contamination.