Ethyl carbamate formation in sub-optimal wine storage conditions and influence of the yeast starter

Abstract

Aim: To evaluate the potential risk of ethyl carbamate (EC) formation in wine by studying its production kinetics at sub-optimal storage temperatures.

Methods and results: The kinetics of EC formation was investigated in 60 white wines obtained from 6 varietal juices fermented with 10 yeast strains. The wines were analysed for their urea content at bottling, then EC formation was monitored during in-bottle storage at < 12 °C for 150 days followed by 152 days at 40 °C. Storage at < 12 °C had no effect on EC formation, regardless of initial urea content ; however, at 40 °C we found a positive correlation between initial urea content and final EC content.

Conclusion: Urea content higher than 20 mg/L in wine kept at 40 °C can produce from 15 up to 30 μg/L EC in less than 5 days. Two yeast strains, La Claire SP665 and Maurivin Platinum, minimised the urea in wine, reducing the risk of EC formation.

Significance and impact of the study: The temperatures used in this study can be accidentally - but easily - reached during sub-optimal wine storage and shipping, and in the presence of substantial amounts of urea, the EC level can exceed the warning levels established by some countries in just a few days. The paper confirms the importance of minimising urea production in wine and controlling temperature during storage and shipping.