Wine Quality Improvement: Defects

By: Denise M. Gardner

Wine defects happen to all of us. Sometimes I wonder if this is the humbling truth about being a winemaker. Even years of education, training and experience cannot 100% guarantee a perfect aging process after a wine has been bottled. However, a winemaker that understands why wine defects occur, how to prevent them during processing, and how to fix a problematic wine can progressively enhance wine quality more consistently than a winemaker oblivious to the potential of wine defects.

Defects and Quality – Is there a difference?

There are components of wine quality that are completely subjective. If you don’t believe me, you can read a series of comments related to a comment I shared in 2014 to the wine community about embracing both Vitis labrusca and Vitis vinifera wines for what they were to consumers and experts alike.

Wine quality may embrace both a lack of defects present in a given wine in addition to an association with a specific wine style. The stylistic component or whether or not a wine is “true to type” falls into a more subjective category.   Identification of wine defects alone is usually more direct and agreed upon wine tasters. However, I will note that some very interesting wines may also have a defect related to the wine’s flavor profile. For example, many traditional, old-style Rioja wines have associated oxidation flavors, but these wines are still found interesting, and of a particular quality, by consumers and experts. I would say the chance of having a defective wine also considered interesting is more of an “exception” compared to a “general-rule-of-thumb.”

What are common wine defects?

There are several technical wine defects, listed below, that can occur in any wine. Brettanomyces-associated off-flavors, the presence of methoxypyrazines, and flavor presence of potassium sorbate or its breakdown products are more controversial, but often noted by wine experts, critics, and writers. In general, the presence of these components may hinder the perceived quality of your wine, and winemakers should be aware of their controversial nature in the wine community.

Table 1: Summary of Wine Defects and Their Common Descriptors

Table 1: Summary of Wine Defects and Their Common Descriptors

While some defects may be measured analytically at the winery (volatile acidity in terms of acetic acid concentration and high free sulfur dioxide content), most require a winemaker to know the key aroma or taste descriptors sensorily (i.e. smell or taste). In this case, the winemaker is the last line of defense when it comes to identifying wine defects and preserving wine quality. This point emphasizes how important production education and sensory training are when it comes to crafting quality wines.

Where to Find More Information

Luckily, today’s winemakers and cellar personnel have a series of resources beyond your usual text book that are available to improve a winemaker’s ability and skill to identify and remediate defective wines.

1. Attend a wine sensory training workshop: Education is truly a tool for every winemaker. One possible workshop available in Pennsylvania includes the Wine Quality Improvement workshop, held annually in January at Penn State. During this two-day workshop, attendees will address all of the above defects: how to identify, prevent, and remediate them. Additionally, a series of hands-on activities contributes to enhancing each attendee’s identification skills that they can apply directly to their winery operation. If you act now, you may be able to register for the 2015 workshop!

Individual sensory training during the 2012 Wine Quality Improvement workshop at Penn State. Photo taken by Michael Black/Black Sun Photography.

Individual sensory training during the 2012 Wine Quality Improvement workshop at Penn State.

2. Purchase a defects aroma-identification kit: Half of the battle for becoming familiar with wine defects is through continuous exposure to standards that exude the characteristic defect aroma or by tasting wine regularly with someone experienced whom can identify the defective wines for you. This action helps improve one’s “aroma memory.” At the Wine Quality Improvement workshop, we provide each attendee with a take-home wine defects kit to encourage further practice with wine defect aromas after they leave the workshop. However, you can also purchase these kits through Wine Awakenings or Le Nez Du Vin. Additionally, Enartis Vinquiry sells a Wine Defects Kit (product #:10-309-0000) in which concentrated defect aromas can be added to an aromatically neutral base wine for aroma training.

Use of wine defects kits to enhance sensory wine defect identification sills. Photo taken by Michael Black/Black Sun Photography.

Use of wine defects kits to enhance sensory wine defect identification sills. Photo taken by Michael Black/Black Sun Photography.

3. Embrace wine criticism from a wine professional: This can be a tough pill to swallow, as the pride of one winemaker may be disliked by the taster. However, this is truly how winemakers get better at making quality wines within any style or price point. All wine styles – from native, sweet Concord wines to premium age-worthy Cabernet blends – have quality parameters and can be evaluated for defects. Find a professional that has credentials in wine sensory or tasting to discuss your wines for constructive criticism. The best professionals will also be able to direct you in terms of improving your current wines held in tanks and future wines that you will produce. You can also contact your local Extension Enologist for guidance on tastings.

Use feedback on your wines to your advantage. Photo taken by Michael Black/Black Sun Photography.

Use feedback on your wines to your advantage. Photo taken by Michael Black/Black Sun Photography.

4. Contract a wine lab to improve your wines: This thought follows #3, as it is similar in theory. Some wine labs (like Enartis Vinquiry or Virginia Tech’s Enology Service Lab) may offer sensory feedback for a fee. This advice can be helpful, as many of these labs have a panel of individuals taste and evaluate the wine. As tasting abilities vary, having more than one person taste a wine for defect identification can be valuable. (Having multiple people available to taste wine as it goes through production should also be considered in cellar.)

5. Work with winery consultants: Your winery consultant may also be your “wine professional” that identifies problematic wines. That’s okay! While winery consultants come at a fee, the value of winery consultants is that they can improve your production practice to meet your needs while also educating your employees (or yourself) on a one-on-one basis. Luckily, each consultant is unique, and finding one that fits the mentality of your production can put your winery on a successful path for years (or generations) to come.

Alain Razungles, Professor of Enology at the Institute des Hautes Etudes de la Vigne et du Vin. Here he is tasting some eastern U.S. wines and providing feedback to the winemakers in the audience.

Alain Razungles, Professor of Enology at the Institute des Hautes Etudes de la Vigne et du Vin. Here he is tasting some eastern U.S. wines and providing feedback to the winemakers in the audience.

6. Attend defect-based seminars at wine conferences: Many of the local and national wine conferences offer talks on wine defects or other quality issues. The Eastern Winery Exposition, Wineries Unlimited, B.E.V.-NY Conference, PA Winery Association Conference and PA Wine Marketing & Research Board Symposium, and American Society for Enology and Viticulture (ASEV)-Eastern Section Annual Conference are all local options for Pennsylvania producers to attend.

Attending wine conferences and workshops can enhance your wine education. Photo by Michael Black/Black Sun Photography.

Attending wine conferences and workshops can enhance your wine education. Photo by Michael Black/Black Sun Photography.

7. Online guides: Don’t forget to keep reading. Both Penn State and Cornell offer free online publications that can be helpful for beginner and expert winemakers. Penn State’s emerging “Wine Made Easy” fact sheet series has already covered sulfur dioxide and hydrogen sulfide Cornell’s “Cellar Dweller” and enology newsletters also offer a plethora of information pertinent to today’s winemakers.

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3 responses to “Wine Quality Improvement: Defects”

  1. eric miller says :

    Nice piece. Well rounded resources & well-said.

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