“My wife, Marjorie, who’s around here somewhere, started the lab in 1978,” ETS co-founder and CEO Gordon Burns says by way of introduction. “More than forty years ago, Marjorie wanted to be a consultant for wineries. Not a winemaking consultant, like the place is flooded with now. A technical consultant. Before Marjorie, the only technical consultant Napa had was André Tchelistcheff. André used to have a lab above Goodman’s department store here in St. Helena. When he passed, Marjorie wanted to fill that role. At that time, she was a medical technologist and was working for several wineries, including Mondavi. She’d also built the wine program for Napa College.”

Marjorie founded and taught the winemaking and wine appreciation program at Napa College in the late 1970s. Gordon and Marjorie met through this program and married soon after.

“It quickly became apparent that there was a need for a hardcore lab business in Napa,” Gordon continues. “So, I poured concrete and built the lab benches in the basement of our house. Business grew, and we moved the office to an old stone house. Eventually, a bunch of winery support services banded together and built this space we’re in now. It’s like a condo situation; we collectively own it. We’ve been here for over twenty years, but we keep needing more space. We have about half the building now.”

At the end of a road tapering off into vineyards, within walking distance of St. Helena’s town center, I was surprised to find such a large office building. Every square inch of the ground floor of ETS Labs is packed with lab benches. A whole section is devoted to just mass spectrometry for the detection and measurement of individual compounds in gases and liquids, which impact (for better or worse) the smell and taste of wine. 

“70% of the testing we do is at a loss,” says Gordon. “So, we better make it up on the other 30%. We have to serve people’s needs by providing everything. It is fortunate and a bane that we do over 90% of all wine analysis performed in America. A hospital lab has a very short menu compared to ours, and the quality control is not as stringent as what we have. Almost all our turnaround is measured in hours or a matter of a few days.”

Gordon Burns was a board member for the FIVS—a global trade federation for the sustainability of alcoholic beverages, similar to the EU’s OIV. “The pillars of sustainability are not just environmental but societal and economic. It is very important that we adhere to a set of standards that embraces all three pillars.”

Unlike many of the French “oeno laboratoires” that are linked to wine consultants, ETS is somewhat unique because it is neutral.

“We don’t sell products or services to fix problems,” Gordon points out. “We are purely a lab. We looked at the European model and decided that we would not do the consultant role. However, we aspire to ensure that the analyses we offer are not just numbers but tools. We want to turn the numbers into practical tools through consultations and seminars. We measure, and we help people apply that information. ‘I offer for your consideration...’ is how I often start conversations.”

The recent game-changing shift in ETS’ laboratory testing approach is going from playing forensic detective to being able to foretell what could go wrong in wine; in essence, they predict the smoking gun before the crime has happened. 

“With Brettanomyces, we used to have to grow the culture on a plate. Now, we use 4EP as a marker. But that still doesn’t answer how many organisms I have. So, we looked into molecular biology; we considered the organisms—yeasts, acetobacter, lactobacillus, etc. Let’s see how we can measure them. We created and licensed a concept to do this called ‘Scorpions.’”

“Scorpions” is ETS’ proprietary means of genetic testing that goes beyond looking for byproduct indicators, which can only determine the nature of the problem after it has occurred. It uses target sequences in the most common wine spoilage microbes—Lactobacillus, Brettanomyces, Pediococcus, etc.—to analyze wine samples for presence with speed and accuracy. This allows winemakers insights into the full range of yeast and bacterial spoilage microbes present in the wine so they can take earlier and less harsh prevention measures if necessary.

“Now our tests are 95% Scorpions and 5% Plating,” says Gordon. “Scorpions are predictive rather than forensic. Winemakers can take less draconian intervention actions to avoid spoilage. We turned the model of microbiology upside-down.”

Eric Hervé is one of the ETS Labs’ head research scientists and a specialist in wine aroma and flavor compounds.

“How many mass spectrometers do you have here?” I ask Eric as we tour the lab.

He thinks for a moment. “I don’t know. Maybe twenty? Oh no, this one is No. 22, so we must have at least twenty-two.”

Eric has been with ETS since 1997, having come here just after finishing his Ph.D. at Bordeaux University, where he conducted research into flavor compounds associated with Cognac and Armagnac. At ETS, his first major area of research was looking at cork taint. His findings led to his development of a way of accurately measuring the presence of 2,4,6-trichloroanisole (TCA) down to one part per trillion. He went on to look at how corks impart TCA in wine, devising a measurement known as “Releasable TCA,” which remains a valuable tool for cork taint assessment today.

Since the wildfires in Sonoma in 2008, smoke taint has become an increasingly important area of research for Eric. If you’ve read any scientific papers published on smoke taint, chances are you will find Eric’s name among the scientists who conducted the research or provided background information. In the aftermath of the 2020 wildfires in Northern California, this is a good time to take stock of where ETS is now when it comes to testing for smoke taint.

Where There’s Fire

Smoke taint occurs when developing grapes are exposed to the smoke from wildfires for any period of time. A number of factors will determine the level of impact the smoke will have on the berries, including the state of berry development during the episode, the duration of exposure, and the concentration and nature of the smoke. 

While solid particles such as ash can be rinsed off the berries, the compounds responsible for smoke taint are far more insidious. There are several ways for these compounds to enter the berry, but the skin is most commonly and detrimentally impacted. For this reason, red wines tend to be more affected by smoke taint since most white wines are made with very little or no skin contact. Once smoke-related volatile compounds have infiltrated the skins of berries, they are impossible to remove without rigorous filtration methods (e.g., reverse osmosis) that strip the wine of character and complexity. Wines thus treated possess an aromatically dulled, flat, and hollowed character.

Once in the skins of berries, the volatile compounds from smoke contact bind with a variety of sugars, forming more stable compounds known as glycosides. Glycosides are non-volatile, meaning that they can’t be smelled. Glycosides are, however, somewhat unstable. Contact with acids or enzymes can break the bond, and the smoke compound becomes detectable again. This bond can become undone during fermentation or when the wine comes in contact with enzyme-containing saliva. It is suspected, but not clearly demonstrated, to happen even when a wine has been in bottle over a period of time. Thus, smoke taint could exist masked in wine for a period of time before it becomes apparent.

Like cork taint, a wine can suffer from a minor, barely noticeable case of smoke taint, or it can be screamingly obvious. The one similar element across all smoke-tainted wines is that they possess aroma and flavor compounds that generally would not come from grapes and/or permitted wine practices such as oak aging or not at such elevated levels. So, for consumers with considerable experience in tasting and drinking wine, the taint can come across as an unusual charry, creosol, medicinal, or ashtray-like character that shouldn’t be there. This said, some smoke taint compounds are the same as or very similar to oak-aging compounds, especially if a wine has been aged in oak with a high toast level. 

Indeed, there are a lot of non-tainted wines that can be described using smoke-related terms such as woodsmoke, chargrill, smoked meats, or just plain smoky. Furthermore, some grape varieties, such as Syrah/Shiraz, naturally contain volatile phenols such as guaiacol and can appear quite smoky without ever having been in contact with smoke. Some of these compounds, such as guaiacol, are also smoke taint markers. Syrahs can thus be quite “smoky” without possessing any smoke taint, and many consumers love them. 

At very low levels, smoke taint probably isn’t so bad, depending on personal preferences and tastes. But above the detection thresholds, that smoky, charry, or ashtray-like smell and taste can become anything from distracting to distasteful. In worst cases, this character can be particularly acrid, with an unpleasant, persistent aftertaste lingering long after all the fruit and winemaking flavors have disappeared. 

Interview with Gordon Burns at ETS Labs

“Our attention came to this topic of smoke taint in 2008,” Gordon begins. “So, we’ve been focused on this topic for a long time. And the research we did in 2008 still holds.” 

How do you approach the topic of smoke taint with winemakers?

“You know, I prefer the term wildfire or smoke impacted,” replies Gordon. “The word taint implies it is always a flaw. We can’t turn smoke into a negative attribute all of a sudden. At ETS, we measure smoke impact in order to put a quantitation on the extent of smoke exposure. We are not commenting on the extent of sensory exposure. We don’t even come up with detection thresholds. There’s a very important role for academia to play here—to establish which compounds impart what flavors in what concentrations and combinations. We are purely measuring the extent of exposure and the level of absorption. We are nowhere near the point where we can say what the sensory impact is. We can simply measure the potential risk of impact. And we can inform winemakers about that risk.”

How do you test for the risk of smoke impact?

“We are currently formalizing our collaboration with the AWRI (Australian Wine Research Institute),” says Gordon. “We have to agree among labs globally on what compounds we’re going to measure, and then we need to form a consensus. And we need to see how well labs are doing. For example, do they all get the same results on the same samples? We have established the set of marker compounds for smoke impact, but this doesn’t mean we’re measuring all the compounds. We’re not implying that. If you consider Brettanomyces, 4EP is just one marker; it is not all the compounds that account for Brett. It’s the same with smoke compounds. A basic marker is guaiacol. When it gets into a particular range, this is when it means there is clear evidence of exposure. But, for a variety of reasons, guaiacol is difficult to detect and measure accurately. This is why many labs can misjudge its presence. 

The insurance companies have set numbers, and, at the moment, they are only using guaiacol as a marker. To be clear, we did not set these numbers. Right now, it can make an enormous difference in the compensation an insured winery receives based on guaiacol numbers. But we’re moving beyond this. We started with two markers, and now we’ve added more. Unlike guaiacol, unfortunately, these new markers are commonly already present in grapes, so we had to establish how much is normal.

To begin, you have to have analytical standards for the compounds you will be measuring, as well as deuterated versions used to compensate for any variations during the testing process. These compounds didn’t exist commercially, so we had to fund their production with our AWRI/Wine Institute consortium, plus some large winery partners. We then distributed this compound to all the participating labs. Once our three major labs got a consensus, we could set the ranges for wildfire exposure/impact. Now, we are helping other labs to get to this stage. This is an enormous accomplishment and a real step forward.

We currently have analyzed 1100 samples from different grape varieties and geographic origins to establish normal ranges. This is completely unique in the world to have such a database of so many different samples. As a result, we now have eight volatile compounds measured by GC-MS/MS (Gas Chromatography coupled with tandem Mass Spectrometry) and six glycosylated compounds measured by LC-MS/MS (Liquid Chromatography coupled with tandem Mass Spectrometry) that we can use to assess smoke impact in grapes. All these other markers don’t replace guaiacol, but they are useful in confirming things. If you’re looking for a remedy to the smoke impact problem, you would need to measure all these markers.”

Many consumers are afraid that smoke taint could become more apparent as wine ages. Does the impact of smoke compounds in wine get worse over time?

“Eric has monitored both volatile and glycosylated compounds in bottled wines for two years. Glycosylated compounds appeared to be much more stable than originally thought. Anecdotal reports that smoke taint can become more apparent with time are most likely caused by the decrease of other aromas masking the perception of smoke.”

This interview with Gordon Burns and Eric Hervé offered a fascinating insight into the progress that is being made in assessing the impact of smoke from wildfires on wine character and quality. Unlike TCA, it appears that the effect of this taint is not so black and white, mainly because some of the major associated compounds it imparts, such as guaiacol, are already present in wines, albeit in smaller concentrations. I hope to maintain an open conversation with Gordon and Eric to follow the progress of their research and pose further questions on behalf of consumers as they arise. Meanwhile, it is heartening to know that our industry has this expert, independent, and rigorous service provider to help ensure the long-term viability of high-quality wine production in the face of emerging challenges such as wildfires and smoke taint.