Tainted Love
The effects of smoke taint on wine.
Words by Jillian Riley, Art by John Hatherly
You can’t turn a corner on the North Coast without hearing the term “smoke taint.” You likely heard about it in previous vintages—2008, 2017, but it’s no doubt becoming a common part of wine vocabulary.
What Happens When Smoke Interacts with Grapes?
Though free volatile phenols from smoke can enter the leaves of the grape vine, the type of smoke taint detectable in wine typically comes from the phenols entering through the waxy skin of the grapes themselves. The phenols then bind with the grape sugars, potentially giving a detectable level of glycoside. This binding may not occur until later in the winemaking process. Thus, markers of smoke taint detectable to human senses may not appear in the grapes or early in the winemaking process, but will become detectable in the finalized product. This is why testing is so important to determine the fate of the wine.
How Is Smoke Taint Measured?
Typically, levels of guaiacol and 4-methylguaiacol are considered the primary markers of smoke. There are extended testing panels available that measure secondary markers of smoke damage, but the former is by far the most common. Most wineries will send samples to an external lab for testing. Because the skins of the grapes are the most affected portions of the fruit, the most useful measurements come from submitting samples of whole grapes, often referred to as berries, or submitting samples of wine when it has completed or is nearing completion of the primary fermentation. There is a period in between when fermentation is just starting and occurring that will not give the most accurate results because the juice will have spent minimal time with the skins. Therefore, it will not yet have absorbed the potential volatile phenols indicating smoke damage.
In California’s North Coast, including Napa and Sonoma, the major testing lab is ETS. When fires are widespread, the lab can quickly become backed up. They have run a wait of up to 2 weeks during the 2020 fires. Because the fires are a relatively new issue for the community, the labs have not had time to grow proportionally.
What Grapes are Most Susceptible to Smoke Taint?
Knowing the majority of damaging phenols end up in the grape skins, it is not surprising to learn that wines made without skin contact or with minimal skin contact will be less susceptible to smoke taint. This includes the majority of white wines.
Grapes that are close to the point of harvest are most at risk for smoke taint. This is why fires in August, September, and October (prime dry season in California) are most worrisome.
How Can Effects of Smoke Damage Be Mitigated?
Many ideas to mitigate smoke taint are still in the experimental phase. The issue is a new one, having grown exponentially along with the effects of climate change.
Some believe fermenting or aging the wine in oak could help mitigate the effects of smoke taint. However, toasted oak (almost all oak barrels are toasted) can release the same compounds (guaiacol and 4-methylguaiacol) as smoke damage in grapes. Therefore, testing the juice (pre-fermentation) or the wine (post-fermentation) will no longer be a reliable indication of smoke damage. Essentially, the winemaker wouldn’t know if these compounds were coming from smoke damage to the grapes or simply from the oak. Thus, this can be a risky move.
Reverse osmosis has been argued as a method to mitigate smoke taint, but many winemakers believe this can rob the wine of many positive aromatic and flavor elements, along with removing what is unwanted.
Addition of tannin has also been anecdotally shown to reduce effects of smoke taint. However, this tannin will also provide the obvious addition of the textural component to the wine, which many winemakers may not desire. Some also have philosophical objections to adding a powder form of tannin, rather than relying on the natural tannins in the grapes.
“Many ideas to mitigate smoke taint are still in the experimental phase. The issue is a new one, having grown exponentially along with the effects of climate change. ”
Active carbon is yet another possible mediator, but it can also dull the natural desirable aromas of the wine.
Addition of yeast hulls is a new option with which many North Coast winemakers are experimenting with. These hulls are the dead cell walls left over after yeast autolysis. They have previously been used to encourage malolactic fermentation that is having trouble occurring naturally. This is a type of fermentation through which almost all red wines and many Chardonnays go through. Some winemakers believe this may be a promising option that will have minimal negative effects on the wine.
Wine is a living thing, and many of these options for mitigation are prime examples of how treating one portion of a symbiotic system can set off a domino effect whereby other portions of the system are damaged. Winemakers have always been building from puzzle pieces, but in vintages with risk of smoke taint, a whole new wild card has just been added.
What We Know. . . and What We Don’t
One of the most important things to understand about smoke taint is how much we don’t understand. While initial testing may show presence of compounds indicating a possibility of smoke taint, it is difficult to know for sure how and if the final wine will be affected. The perception of smoke taint also tends to increase as the wine ages. Because most vintages affected by fires are recent, we don’t have many case studies for aged wine with smoke taint. Winemakers are forced to make quite a few educated guesses.
2020—An improvisational vintage
Should We Avoid 2020 Wines from California, Washington, and Oregon?
The short answer is no. Writing off a vintage as a whole is always something to be cautioned against. Will 2020 be an easy vintage? Certainly not. Will all wines produced be excellent? No. Will excellent wines be produced? Absolutely.
It is important to understand that fires may affect many vineyards and wineries in a given area, but they will rarely encompass every portion of the area. There are a number of portions in California, Washington, and Oregon that will not have experienced any smoke taint. Additionally, there are a number of wineries who make wine from multiple vineyard sites. The superior wineries will ensure they are producing wines of the best quality. They may sell some excess as bulk; they may refuse some grapes, but they have a mind toward ensuring their names are not emblazoned on wines of poor quality. There will still be exceptional wine to come out of this vintage.
Cliffs Notes for Navigating Purchases of 2020 Wines
Almost all whites will be fine! Don’t halt your purchase of a 2020 Sauvignon Blanc because of fear of smoke taint. Most Sauvignon (as well as the majority of other white varieties) was picked before the second round of fires, and most of it will have no skin contact. Thus, it is unlikely to display signs of smoke taint.
Buy from wineries you love and wineries you trust.
Avoid bulk and super large production wineries. If someone produced more than 10,000 cases in 2020 in one of the affected areas, it’s a good indication they were not overly concerned with quality.
There will still be some ageable wines made this vintage—again, trust the wineries who have proved their trustworthiness vintage after vintage, but if you want to play it extra safe, purchase styles of wine meant to be consumed in their youth (first 5 years). Because smoke taint tends to present more with age, wines consumed in their youth will be less likely to exhibit signs of smoke damage.