Removing Brett off-aromas from affected wines
As gatekeepers, wine writers have clear opinions on what a flaw is, and they drive those messages directly to consumers. Using the word “flaw” in a wine’s description suggests it is of lower value. One great thing about people’s notions of value is that they vary widely for everyone, especially on the subject of “Brett”.
Brettanomyces bruxellensis (a.k.a. Brett) is considered a spoilage yeast by some winemakers and a resourceful agent of sensory transformation by others. Most wineries agree that Brett takes away from wine quality, but some wineries say they use Brett to add complexity and interest to their red wines [1]. Most winemakers place the highest value on the truest expression of a vineyard and are fierce defenders against Brett’s impact on their products.
The sommelier at your favorite expensive restaurant may have a more egalitarian view on the subject. A small amount of “brett-i-ness" in a wine can be interesting to some. Too much can lead to spoilage and disappointment.
Brett’s metabolism makes some wines smell less like flowers, honey and fruit, and more like goat cheese, wet dog and horse blankets. The primary odorants of Brettanomyces spoilage are 4-ethyl phenol (4-EP) and 4-ethyl guaiacol (4-EG). Often called ethyl phenols, they represent a primary class of compounds that Brett produces when it’s growing uninhibited in a wine. These analytes are also the easiest to quantify in the lab, so they have become the standard measure of a Brett affected wine [2].
Targeted filtration removes volatile phenols
So, what does a winemaker do when they have a little too much Brett character in their blend? Methods of masking or removal include traditional methods like changing oak profiles, fining with dairy products, fine lees, or using reverse osmosis and carbon [5].
Few winemakers opt for these methods because they alter the structure and mouthfeel and increase processing time, not to mention the potential allergen and labeling issues. Blending with non-affected wines to get the concentrations below an offensive threshold is an option, but it can create other problems.
Tailoring the sensory impact of Brett in your wine is now possible using amaea BTx. A new treatment option that allows winemakers to be more targeted and recover more value in Brett tainted wines without additives and with much lower structural impact than other methods.
amaea BTx uses molecularly imprinted polymers (MIPs) which are specifically imprinted with volatile phenols to act as a selective filtration medium, eliminating the need for animal-based additives or carbon, both of which can be indiscriminate in their activity.
4-EG Analysis
4-EP Analysis
Above: Bench top example of 4-EP and 4-EG removal from a 2005 Brett impacted wine using amaea BTx molecular filtration technology.
How much does Brett cost the California wine industry?
In 2016, a survey of over 120 California winery production personnel from all over the world demonstrated that Brett is undesirable in the winery. A follow-up study tracking wine quality downgrades due to Brett could be extensive. Production efforts to prevent quality losses from Brett can cost the average winery up to 5.0% of annual operating expenses [3].
Identifying and monitoring individual barrel lots with Brett is one cost factor. The extra work to then remediate, or blend away expensive lots creates additional logistical headaches for winemakers. Expenses from downgrading lots can be even more significant than the extra sanitation, remediation and rework.
Efforts to eliminate Brett from the cellar are costly. Early detection of affected lots is the best way to prevent expensive losses [4]. If you don’t catch Brett in the act through testing early and often, then remediation is the next best option. amaea BTx selective filtration is fast, efficient, and way more targeted than other treatment options, without the need to use additives or do special labeling. Contact our team to schedule your benchtop trial and arrange for treatment.
Author: Torey Arvik, VP of Applied Research
References:
Wine Enthusiast online article https://www.wineenthusiast.com/basics/the-divisive-impact-of-brettanomyces-in-wine/
ETS Laboratories Technical Publication https://www.etslabs.com/publications/publication/11
Brettanomics I: The cost of Brettanomyces to the California wine industry. Journal of Wine Economics, Vol. 16, issue 1, 2021. pp. 4-31 DOI: https://doi.org/10.1017/jwe.2020.20https://www.cambridge.org/core/journals/journal-of-wine-economics/article/abs/brettanomics-i-the-cost-of-brettanomyces-in-california-wine-production/295D206007B358EC1B07CEF4879BE06B
R. Ullom and T. Arvik. Brettanomyces: Who Cares and at What Cost? Wine Business Monthly's Third Innovation + Quality Conference, March 2, 2017. Krug Winery, Napa, California
Barbosa, A., T. Hogg and J.A. Cuoto. The influence of selected oenological practices on the sensory impact of volatile phenols in red wines. J. Int. Sci. Vigne Vin, 2012, 46, n°2, 131-138