Ever Wonder? How Does Temperature Affect Wine Fermentation

There’s a lot of chemistry that goes into making wine. And we learn from basic chemistry that heat is a catalyst. When heat is applied to a chemical reaction, it speeds things up. So, temperature plays a role in the fermentation of wine.

The higher the fermentation temperature the faster the yeast will convert the grape’s natural sugars to alcohol. But, winemaking is a slow process. From the growing of the grapes to the aging of the wine. And, fermentation is no exception. Winemakers don’t want to rush this process. So, they actually take steps to cool-down, the thus slow-down, the fermentation process.

If a wine is fermented at too high a temperature, it can lack character as well as remove any terroir that the winemaker was hoping to capture. By fermenting a lower temperatures, a winemaker preserves the fruit flavors and helps preserve the subtle elements that terroir can add.

Red wines are typically fermented between 70 and 85 degrees F (20-30 degrees C). This temperature range results is richer colors, good tannin levels and richer fruit flavors. Fermentation temperatures that approach 90 degrees F can result in “cooked” flavors making the wine taste stewed, prune-like or raisin-y.

White wines are typically fermented even cooler than red wines at temperatures between 45 and 60 degrees F (7-16 degrees C). This helps preserve a white wine’s bright fruit aromas and flavors while providing balanced acidity levels.

Proper Wine Storage -- It's Starts at the Store!

A lot of people are concerned with ensuring that they store their wine properly. And, that’s important. But to ensure you are getting a wine that’s at its best, you also need to take into consideration the store where you’re buying your wine.

Sure, there are potential storage issues between the winery and the store. Like the method of shipment and the time of year (e.g., getting too hot). But, how your local wine shop or store handles your wine is very important because it may sit on the shelf for a longer period of time.

While visiting the eastern U.S. last winter, I took a short snowy walk to a place where I’ve purchased wine before. While it was below freezing outside, the store was nice and warm. But, that caused me to pause. As I took off my layers to be comfortable while shopping, it struck me that it was probably in the high 70s F in the store, if not 80 degrees. While that’s a comfortable temperature for shoppers on a cold winter day, that’s not anywhere near an ideal temperature for a wine.

Maybe you’ve noticed that most grocery stores are kept quite cool. That’s intentional to help keep their merchandise as fresh as possible. And that’s especially true for wine. While most guidance for wine storage is in the 50s F, even a “cool” temperature in a store will be in the high 60s. While that’s fine for short amount of time, finding an older bottle of a nice wine that been sitting at nearly 80 degrees F for who knows how long, could be an issue.

So, just keep in mind that while you may have the ideal wine storage system at home, you also must ensure that the wine you’re putting into it has not been damaged while in the store.

Oh! And also consider where the wine is placed within the store. I’ve seen too many wine shelves in direct sunlight. That’s not good either!

Cheers!

Ever Wonder? - Does White Wine have to be Chilled?

A few months back a friend of mine told me that, in the past, he really didn’t like white wine. He said white wines just didn’t have as much flavor as red wines. He preferred the flavors of a red wine.

But, on a wine tasting trip he went ahead and tried a Chardonnay. And he really liked it!

What was immediately obvious to him was that the Chardonnay was very lightly chilled as opposed to refrigerator temperature.

His experience with white wines had all been with very cold white wines. And the chill had taken all the flavor out of the wine.

This is indeed true. And, often the reason that people like their wines (including red wines) heavily chilled — to make them have less flavor.

So, the answer to the question is no, white doesn’t have to be chilled at all. But a light chill will allow you to experience the white wine as it was intended by the winemaker.

A rule-of-thumb that I’ve always used is that for white wine is that you should take the bottle out of a standard refrigerator (which is typically 35-40 degrees F) approximately 30 minutes before you want to serve it. That should leave a chill on it. Or, if you own a wine refrigerator, you probably already know that it should be set to approximately 50 degrees F for white wines.

But, as my friend found out, the serving temperature of wine generally is a matter of personal preference. Whatever your preference, enjoy!

How Does Wind Affect a Wine?

I recently had a friend return from doing some wine tasting in Napa. While he said he enjoyed the wine, he did complain that it was windy and cold. And, he said he was told that the wind helped the wine. So, he asked me "How does wind affect a wine?"

Luckily, I had recently been doing some reading, and this exact situation was described. It turns out that it's not just the wind, it a cool wind that helps.  And, as is true with many of the premiere wine growing regions, Napa is helped by the cool afternoon breezes that come in off the ocean.  These cool winds actually cause the leaves in the vineyard to close-down their tiny pores (stoma). Without going any further into plant botany, this slows down the ripening process during the growing season. And, slower ripening results in grape skins that are thicker along with smaller berries (i.e., grapes) and smaller bunches.  This produces concentrated flavors and, in red grapes, a bit more tannin. It can also help with increased acidity. All good stuff for making wine.

So, when you visit wine county and feel the cool afternoon breezes, don't complain. They are helping to make the wine even better. Cheers!