A Smoky Aftertaste: Keeping Wildfires Out Of Your Wine Glass

IRA FLATOW: If you’re into wines– and so many of us are– then we need to have a serious talk, because California, Washington, and Oregon are three of our biggest wine-producing states, and they’re also some of the states most prone to wildfires. Yes, the West Coast is in wildfire season, which makes us wonder– how does smoke impact the wines that come from this region? And what could this mean for those of us who enjoy a Napa Valley merlot or an Oregon pinot noir or a Washington state white?

There’s a whole area of food science research that is looking into this important question. And joining me now to tell us a little bit about it is my guest, Cole Cerrato, assistant professor of food science at Oregon State University in Corvallis. Welcome to Science Friday.

COLE CERRATO: Hi, Ira. Thank you for having me.

IRA FLATOW: You’re welcome. OK, let’s get right into it. If a wildfire is burning near a vineyard, is that smoke going to impact those grapes and the wine?

COLE CERRATO: Potentially. Like anything, it will depend on how big the fire is, how much smoke is getting put into the air, how close it is. There’s a lot of research that’s looking into that. But the overall effect that you would see in the subsequent wine that is made is the wine will take up these chemicals from the wildfire that we tend to associate with that smell. And the grapes will pull in some of those chemicals, and during the fermentation process, either the grape or the fermentation is changing some of this chemistry.

And so the wine that you would eventually drink from this can sometimes have an ashy flavor to it. Sometimes it is a campfire type of flavor, like a day-old campfire. Myself, I’m very sensitive to certain types of chemicals that often put off flavors that resemble tire fires, if you will. It’s not a very pleasant experience.

IRA FLATOW: Wow. Wow.

COLE CERRATO: Yes. It can be very strong, and I think there’s something to be said about people’s sensitivity. But it’s not like anybody is going to be having any of these wines on the market anyway.

IRA FLATOW: No. But could there be a market for it? Could people say, hey, you know, I kind of like this smoky, burning fire taste, and say, hey, I’ll drink that wine?

COLE CERRATO: I mean, potentially. I believe it’d be probably very clearly labeled if that was the case. They’re not very likely to just buy a typical wine off the shelf and say, hey, this tastes smoky. But we have some sensory experiments that we do in our lab. And when we do some of these smoke trials, there have been a couple people that like some of the smoky wines. So potentially, there could be a market.

IRA FLATOW: Yeah. You know, because we’re a science show, and a lot of our listeners like to get really into the weeds about the chemistry, talk about the specific chemicals that affect those grapes.

COLE CERRATO: So what’s occurring– coming from the smoke itself, there are a series of compounds called phenols that are in the smoke. And what we think is happening is that these phenols are attaching to the grape skin. There’s an interaction between the skin and these volatile compounds. And eventually, these compounds are absorbed into the grape itself.

IRA FLATOW: Now, I know that pinot noir is huge in Oregon, right? Is this particularly bad for those Oregon vineyards?

COLE CERRATO: Pinot noir is incredibly sensitive to these wildfires. Our red wines typically tend to be more sensitive because these wildfire molecules go into the grape skin itself. And because a lot of the red wines are produced on skin– they are fermented with the skin in contact– they tend to extract a lot of those chemicals out of the skin, whereas white wines, such as chardonnay that we have here, they’re still affected, but they often don’t pull out some of that kind of campfire effect that you’ll get out of this. So the chemistry changes. It’s just in a slightly different way.

IRA FLATOW: Yeah. So the pinot people are a lot more worried than the chardonnay people are.

COLE CERRATO: Correct. And there’s often a big overlap.

IRA FLATOW: What is the industry watching for, then, as the wildfires get worse in some places?

COLE CERRATO: I think the industry, first and foremost, is looking at the same things that everybody else is looking at, like is this going to affect them more than just from the wildfire smoke, but directly? The other thing that they’re looking for is not necessarily whether or not they can prevent this, because the smoke is already in the air. But what they can do is get more information, and that’s when they start sending in samples for testing to see how much some of these compounds, these volatile compounds, are getting into their grapes so they have more data to work with to make their decisions.

IRA FLATOW: And what are the vineyards then doing now if their grapes are affected by smoke? Do they just throw out the affected grapes?

COLE CERRATO: There’s a number of things, post-processing things that they can do they have at their disposal. It really depends on how effective they are– again, like how close that wildfire is, how much smoke there was. So depending on the flavor experience that they are getting from their wines, some places are able to successfully blend out the smoke smell or the smoke taste. So they can blend it with other types of wine or unaffected wines from previous years. There are a number of ways that they can do some chemical amelioration, as well, where they will use things like activated charcoal, reverse osmosis. And again, these are for the wines that are typically not heavily impacted, but are slightly impacted, so that they are able to reduce the amount of that sensory smoky experience in their wines.

IRA FLATOW: Well, if you consider that these fires are– this is the new normal now, could an answer to this solution possibly be a more, how shall I say, smoke-resistant grape? And is it possible to develop one?

COLE CERRATO: We are looking at a number of ways that kind of address this question. I don’t know much on the side of developing a different type of grape, coming from the chemistry perspective myself. So my point of attack is always going to be looking at ways that we can either prevent it with some sort of chemical intervention– is there a way in the back end that we can prevent this flavor with another type of intervention that is similar to what they use now but more specific to these compounds?

IRA FLATOW: So in that vein, what’s next for your research? What do you want to know?

COLE CERRATO: The things that I want to know are what exactly are all of the compounds? Are there certain compounds that are more impactful towards the flavor profile of a smoke-impacted wine? And once we know this information, we can start developing more specific strategies to target these molecules so that we can remove this without affecting the overall quality of the wine itself, because we would still like to give the wine industry great quality wine without needing to impact any of the chemistry that they want in their wines.

IRA FLATOW: Thank you, Dr. Cerrato, for taking time to talk with us.

COLE CERRATO: Thank you, Ira. Thank you for having me.

IRA FLATOW: Cole Cerrato, assistant professor of food science at Oregon State University in Corvallis.

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