Harnessing improved understanding ofBrettanomyces bruxellensisbiology to mitigate the risk of wine spoilage

Abstract

In the competitive global wine industry, production of wines reflective of their place of origin is critical. While the evidence is mounting that microbial populations in vineyards and wineries differ geographically and represent an important component of ‘terroir’, there are some microbial influences on wine style that are generally considered undesirable, regardless of whether the offending species is part of the natural winemaking microflora. Brettanomyces spoilage of wine remains one of the most important microbiological issues facing winemakers. While most prevalent in premium, barrel‐aged reds, ‘Brett’ also affects sparkling wines and fortified wines. This review will cover recent advances in knowledge of the biology of this species alongside practical implications for risk management in the winery. For example, insights into genome evolution and population genetics will be discussed in the context of potential for emergence of more sulfite‐tolerant strains. Strategies to reduce the risk of Brett spoilage will be updated, with discussion of alternative approaches drawn from other food and beverage sectors that may allow winemakers to reduce their reliance upon the common preservative sulfur dioxide.

Brettanomyces bruxellensis population survey reveals a diploid-triploid complex structured according to substrate of isolation and geographical distribution

“…Sulfur dioxide is the most common antimicrobial agent used in winemaking. However, very tolerant B. bruxellensis strains have been reported 36 . Particularly, in Australia 92% of the isolates are genetically close to a strain that has be shown to be triploid by genome sequencing and highly tolerant to SO 2 (normal growth at more than 0.6 mg.L −1 mSO 2 ) 34 .…”

“…This phenotypic variation makes it difficult to predict the spoilage potential of B. bruxellensis and is therefore a major concern for winemakers. For example, across several studies the concentration of molecular SO 2 (mSO 2 ) required to stop B. bruxellensis ’ growth ranged from 0.2 to 1.0 mg.L −1 36 . This observed variability was at least partly due to the use of different strains.…”

Brettanomyces Spoilage in Albanian Wines Assessed by Culture‐Dependent and Culture‐Independent Methods

“…An effective SO 2 management can keep Brettanomyces yeasts under control (Curtin, Varela, & Borneman, ). This indicates that the measurement of the ratio of free and total SO 2 can be successfully used to control this spoilage yeast.…”

Microbiology of winemaking

“…Brettanomyces bruxellensis readily proliferates and can survive in wine for long periods, particularly following alcoholic fermentation and during wine ageing in oak barrels 19 . This yeast can cause numerous wine faults, including turbidity in unfortified wines, excessive volatile acidity in sherry, mousy taint and rancid isovaleric acid.…”