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Keep the Smoke in the BBQ: A Run-Down on Wine Smoke Taint

Natalie Burnham

As conditions change around the grape-growing world, the effects of wildfires on wine grapes are perhaps more prevalent now than ever. Aside from the actual burning of grapes and vines, smoke damage to wine grapes, known as smoke taint, is one of the most pressing issues of modern winemaking.

What is wine taint?

Wine taint can come in all shapes and sizes, but the defining factor is an externally-caused compound that typically results in a wine being rejected. The most well-known form of taint is cork taint, though this affects less than 3% of wine bottles. Cork taint, composed of either 2, 4, 6-trichloroanisole, or 2, 4, 6-tribromoanisole, is caused by bacterial growth in either the cork of a bottle or the cardboard or wood of storage palettes, leading to aromas of wet dog or mold in extreme cases. A somewhat silly-sounding taint is the ladybug taint, from the over-existence of ladybugs in vines. This causes extreme levels of vegetal aromas, such as green bell pepper or tea leaves.

a fire in a dry vineyard

What is smoke taint?

Smoke taint, predictably, is caused by grapes exposed to smoke. As material around vineyards is burnt, compounds are released into the air. Similar to standing too close to a campfire for too long and the smell sticking to our hair or clothes, if wine grapes are exposed to the smoke for too long, the smell also sticks. It takes roughly a week under smoky conditions for berries to take up the compounds, and the riper the berries, the more susceptible to smoke taint they are. The most common smoke taint compounds are guaiacol (which smells like sweet smoke or smoked bacon) and methyl-guaiacol (which smells like spicy smoke), though compounds can also hold more extreme aromas, such as cresol, which can smell almost fecal.

In smoke, these aromas are volatile, meaning we can perceive their odors. However, as they are taken up by the grapes, they become soluble and lose their aromas. Because of this, it can be extremely difficult to gauge the damage to smoke tainted grapes, as these aromas stay hidden until the berries go through fermentation. Once berries are fermented into grapes, those aromas become volatile again; the smoky aromas and flavors appear on the nose and the palate as wine is smelled and tasted.

How can we reduce the effects of smoke taint?

The simplest way we can reduce the effects of smoke taint is by implementing fire prevention and management tactics in our vineyards. One way that vineyards can do this is the implementation of livestock, which can help to graze and reduce flammable material in vineyards. Another way to reduce the effects of smoke taint is, after harvesting grapes, removing skins from the grapes. Though the compounds can become soluble in the grapes, the vast majority of the smoke taint will be held in the skin, so removal from the skin can be a crucial step in preventing smoke taint. Before fermentation, corrective (but expensive) enzymes can also be used to help reduce the effects of smoke taint.

How do we assess smoke taint damage?

If damage is suspected, a winery can either send full berries to be tested for smoke taint compounds or can go through small-scale fermentation to go through smoke taint testing. For best results, testing facilities recommend sending both grapes and wine. If the smoke taint compounds in wine are found at too high of a concentration at either level, the grapes/wine are considered 'tainted', and the winery must decide its next steps.

a young grapevine shoot in front of a sunset

What can we do after the fact?

After discovering smoke taint in wine, a winery has a few options. If they have crop insurance, they may be able to file a claim to help with the financial losses. If they don’t have crop insurance, they may be able to go through the process of smoke taint removal in wine. This primarily is done through reverse osmosis, but this is an extremely costly process. Many wineries end up simply dumping the smoke-tainted wine because of the high cost associated with correcting them.

One bright side to smoke taint is that there is no annual bleed-over: impacted grapes do not cause the next year’s harvest to be impacted.

As wildfires continue to increase, especially in wine country, smoke taint is a more prevalent issue now than ever. An estimated 5-10% of California wine grapes are impacted by smoke taint. With increased fire and smoke preparedness and increases in technology, we can only hope that number decreases to continue to revolutionize California’s wine and grape industry against a major challenge posed against it.

Rest assured that we at Gold Medal Wine Club meticulously test our wine before featuring, so you're guaranteed to never receive a bottle affected by smoke taint.