Michael Reibel Boesen

November 24, 2022

🍷🌍 Tasting climate change

Let’s face it I’m deep into the bottle.

That came out wrong.

I have a quite deep interest in wine. It was a bottle of Domaine Bachey-Legros Vielles Vignes Chassagne-Montrachet 1er Cru ‘Les Petit Clos’ 2013 or in other words a bottle of fermented Chardonnay grapes from old vines harvested in 2013 from a premier cru (2nd best tier) vineyard called Les Petit Clos in the Chassagne-Montrachet area in Burgundy, France.

There is Le Petits Clos 👆

Back then I was just completely baffled that a wine could taste like that. Back in 2018 it was for sure like throwing pearls at a pig 🐷 but something triggered me. As I learned more and more I realized how magical a beverage wine is. Since 2020 I’ve done wine tastings for family and friends and in 2022 took it to the next level by actually enrolling in a formal wine education via the WSET (for which I’m currently studying for level 3 and probably the last level for now as I have other things to work on).

But anyway, let’s move on.

Here’s how you make it (in very broad strokes) - read from left to right.

We all know what grapes taste like. Like grapes right? But wine doesn’t taste like grapes usually with exceptions e.g. varieties like Muscat. The process of fermentation that the yeast carries out transforms the sugary juice into alcohol but also all kinds of aromatic compounds. This means that you can have a Chardonnay that tastes like a pineapple, a Pinot Noir that tastes like cherries, a Merlot that tastes like plum, a Cabernet Sauvignon that tastes like black currant just to take a few “stereotypes”. True, the winemaker can “add flavors” to the wine by maturing it in new oak (which will add flavors like vanilla to the wine) or encourage malolactic conversion which will make the wine taste like butter and other things.

(You can of course do the same with any kind of fruit, but vitis vinefera (the vine species used for wine production) is the only one (to my knowledge) that can develop such complex aromas and are this temperature dependent.)

The true underlying so called primary flavors that are the by-product of fermentation of the grape juice and nothing else have an interesting property: Which flavors develop are heavily dependent on the temperature in which the grapes are grown (as well as soil type but that influences the more mineral part of the flavor spectrum like stones etc as well as structure - another story).

This means that a if Pinot Noir from Casablanca Valley in Chile (which is one of the colder areas) tastes like bell pepper, it means that the grower had to (or chose to ignore) unripe berries. The same grape grown just a few kilometers away in the much hotter Central Valley will taste almost like red fruit jam (if it can even grow there). And the change is gradual: A Chardonnay from a cold area like Chablis will taste of apples and lemon. But a Chardonnay from warm Napa Valley will taste of tropical fruits like pineapple and mango and likely also a bit of citrus fruit. So the spectrum of flavors for each grape variety change with rising temperature. Chardonnay goes from apples (cold) to pineapple (hot) for instance.

(Stop and reflect about that for a second. Isn’t that insane? It kind of reflects growth of apple trees and pineapple trees as well. Apple trees can grow in cold climates and pineapples in hot climates. Is yeast the masters of the universe or what?)

But flavors are not the only thing that changes with temperature. The so called structural components like acidity, body and alcohol also change. In cold conditions grapes will have less sugar and high acidity. High acidity will make the wine feels lighter on the palate. In warm conditions acidity will drop hence usually causing an increase in body which in large part is due to higher alcohol which adds weight on the palate.

I once heard the great wine youtuber and Master of Wine (yes that’s a degree and in fact the highest possible) Konstantin Baum say that “there are no climate deniers among wine enthusiasts” (or something like that can’t find the exact quote nor video I heard it in). An interesting sidenote: The Koch brothers of fossil fuel fame and fortune are known for having an insane wine collection.

And this is why there are no climate deniers among wine enthusiasts: Rising temperatures and changing climate literally changes how wines taste. Isn’t this cool? (very bad pun intended) You can very literally taste climate change in wine.

In fact wines are so finicky that they they all have a vintage year (the year the grapes were harvested) on the bottle. This is because the weather patterns from one year to the next might change the flavors and structural components significantly. (But admittedly this is a very poor user interface for a quite complex product - planning to write more on that in a later post).

For those who are less taste oriented and more data oriented. I hinted that alcohol levels are higher in warm conditions. Why is that?

More heat and sunlight increases the sugar levels in the grapes. More sugar in the grape juice means more sugar for the yeast to eat. More sugar means more yeast poop, which means more alcohol. So back to the data. Below is a graph that shows how alcohol levels in wine have increased over the past 30 years in various regions.

Source: https://www.liv-ex.com/2021/06/liv-ex-abv-data-shows-rising-alcohol-levels-30-years/

So warmer temperatures these past 30 years have caused sugar to increase and thus alcohol.

The climate denier reading this might notice: “Hah! You see climate change is stagnating since alcohol levels is not increasing any more!” 

But no.. Excessive alcohol will cause wines to be unbalanced. This happens faster for light bodied grapes like Pinot Noir (Burgundy red) and Nebbiolo (Piedmont red). As you can see Californian reds (typically Zinfandel and Cabernet Sauvignon) can go higher and still feel balanced. So the winemaker have to adapt to this situation in order to make a product that they can sell. So in the vineyard this translates to picking grapes earlier or making sure grapes are more shaded such that the grapes doesn’t increase sugar levels beyond a certain point. But all of these factors change the product of course, not just alcohol levels.

So contrary to many industries out there: This is an industry that is actually actively adapting to climate change. And have been at least since the early 2000s. And the reason is very obvious: You can’t continue to make Champagne in Champagne with rising temperatures. That’s why there’s now a fledgling if still young sparkling wine industry in cold and rainy places like the UK which actually have a climate similar to Champagne in the old days. As the temperature rises wineries will have to move further north or south (depending on hemisphere) to make the same wines as they used to. But if you move to a different area the soils and other factors change, which will inevitably change the final product anyway. So the wines we see on the market today will likely become extinct in the decades to come. 

So for all you climate deniers out there with vast wine cellars of fossil fuel fortunes, I’d be very happy to take your fake fermented grape juice off your hands cheap since you clearly can’t “believe” in it since you don’t “believe” in climate change.

And for the rest of you: Enjoy the wine you drink. It won’t taste the same next year — due to climate change.

Cheers 🥂

About Michael Reibel Boesen

Dad 👨‍👩‍👦‍👦, builder (🤖⌨️🏢), 💌 Weekly Climate, 🚁📸photographer, 🎧vinyl record collector and reseller, 🥃 distiller (Gefjun), 🎸guitarist, 🎹pianist, 🍷winenerd (WSET3), 🏃‍♂️runner and 🤓engineer/PhD.