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5 Big Ways That Winemakers Manipulate Your Favorite Wine

We talk frequently about the benefits of our approach to winemaking. We believe strongly that the best winemakers make wine with the least amount of intervention, and that the best winemaking is done primarily in the vineyard, before the grapes are harvested. 

Why, then, do so many winemakers use additives? When winemakers add things to their wines, what can they accomplish? Here’s a look at some of the most common wine additives and the reasons for adding them:

What’s the difference between native yeast vs. conventional yeast in winemaking?

What has the biggest impact on a wine’s flavor? The grapes, of course. After the grapes, however, the yeast used to ferment a wine most significantly determines the flavor. Using native yeast (aka indigenous yeast) is the purest expression of a vineyard, because that exact combination of grapes and yeast exist in only that exact place. A That combination of factors, along with climate and soil, make up what we call in the business the terroir, or a wine’s unique sense of place. 

However, native yeast are not as controllable as lab-grown (aka conventional) yeast. Some native yeast will stop fermenting at lower ABVs, meaning if a winemaker has a harvest with a very high sugar content, that yeast won’t be able to ferment all of those sugars before the resulting alcohol kills the yeast. This results in a lower-alcohol wine, which until recently was an undesirable trait, as well as a higher amount of unfermented sugars, known as residual sugar or RS, that will make for a sweet tasting final product. As many winemakers have targeted much higher ABVs, conventional yeast has been the only way to consistently get those results. When using this conventional yeast, winemakers give up some of their wines’ unique characteristics in the tradeoff.

When is sugar added to wine?

One of the touchiest subjects in winemaking is around the addition of sugar to unfermented grape juice, a process known as chaptalization. The sugar content of wine grapes, aka brix, is one of the most important factors that determines what kind of wine they will become. A higher brix is desirable in most winemaking practices. The easiest way to achieve a higher brix is to leave the grapes on the vine longer, allowing them to ripen naturally. However, as grapes ripen they become more susceptible to insects and rot, and the cost to monitor, etc. increases as well. Knowing exactly when to harvest is a careful balancing act, maybe the most important decision a winemaker will make in each vintage. Manipulating the sugar content after harvest is a way to make up for choosing to harvest the grapes too early.  

In some parts of the world, such as France, Germany, Oregon, and New Zealand, adding sugar is common and allowed. In others, such as Italy, Spain, and California, it is illegal. In areas where adding sugar is not an option, winemakers can add a concentrated grape must (essentially grape juice), for example, to achieve the same effect. These sugar manipulations can have a huge impact on the finished wine, boosting ABV by as much as 3%. In most cases, this is done in a responsible manner, but it is also a way for large industrial winemakers to make palatable wine from subpar grapes. It is also a way for winemakers to smooth out vintage variations in their wines, something that is a common thread in the use of additives.

How does pH level affect the taste of wine?

Another big component in a wine’s flavor is the acid in the grapes. Winemakers measure the pH level of grapes when they’re still on the vine/in the vineyards, and along with brix (see above) use that information to decide when to harvest. If a wine’s acidity isn’t where a winemaker wants it, there are ways they can boost or reduce the acidity. Adding chalk to wine lowers the acidity, boosting the pH, while adding any combination of tartaric, malic, or citric acid will boost the acid. Boosting acid is one of the most noticeable things a winemaker can do, and when done poorly the flavor of artificial acidity can be very noticeable.

What does sulfur do in wine?

There are a number of chemicals added to wine in order to stabilize various aspects of the wine, from color to flavor to texture, because otherwise it will continue to ferment. The most common stabilizer is sulfur, used as a preservative in most wines. Some sulfur is produced naturally in the fermentation process, and many winemakers add additional sulfur to help keep the wine stable. While there is a small percentage of the population with an allergy, most people experience no negative reaction to sulfur in wine. On the other hand, a chemical like dimethyl dicarbonate, an industrial chemical that is also used to preserve and stabilize wine, is safe once added to wine and fully hydrolyzed but extremely toxic when applied, requiring cellar or vineyard workers to wear full hazmat suits when using it. Our opinion is that no tangential benefit to a wine’s shelf life is worth the existence of a chemical like that.

How many additives are allowed in wine?

All in, there are more than 70 FDA-approved additives for wine (the number is slightly lower in Europe.) These additives can be used to manipulate any of the aspects of a wine we discussed above, and many have multiple uses. Are any of the additives above dangerous for consumers? Probably not. There have been extensive studies done and the FDA has approved everything mentioned. But in one way or another, every addition takes a little something away from the uniqueness of that wine.

We look at winemakers who over-manipulate their wine a bit like a singer that uses autotune—if they had a good enough voice, they wouldn’t need the tool.