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What Chemicals Are In Your Wine?
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Do You Know What is in Your Wine?

Wine is made to be consumed. It’s been made for thousands of years without too much fuss or bother. As the years pass, we have become better acquainted with the process of fermentation, and have developed techniques to fine-tune wines for flavor, mouth-feel, color, structure, and much more. Long before man had high-tech equipment or the chemistry expertise to tell us about wine’s structure and makeup, the process was wrought with trial and error.

White Pinot Gris vs Skin-Contact Pinot Gris - photo by Flickr user jimfischer https://www.flickr.com/photos/jimfischer/

Photo by Flickr user jimfischer https://www.flickr.com/photos/jimfischer/

As the centuries passed, we have gotten much better at planning for the inevitable, and have figured out ways in which to craft a wine in particular styles, using chemical and organic additions to produce the desired results.

Far from being a natural wonder, many wines go through a complex process of manipulation before they make it into your glass. This article isn’t meant to scare or provoke, but to offer insight into what could well be in your glass, and why.

Industry Chemistry

It’s never been the intention of the wine industry for you to know every little thing that goes into your wine. However, the processes are no secret. Chemical additions are normal in virtually all wines, from Two Buck Chuck to Chateau Petrus. The types of additions depend on what purpose they serve to the resulting wine, and could be for any one of the following reasons:

•    To balance sugars or acids, or to correct a fault
•    Adding nutrients to support yeast function
•    Adding cultured yeasts to yield specific flavors
•    Adding sulphur as a preservative
•    Adding tannin or other enzymes as a preservative and to stabilize color
•    To create a consistent product or craft a ‘house style’ that can be replicated year after year
•    Adding perceived value by manipulating flavors, mouth-feel, etc.

Sugar, Acids and Yeast

The formula for fermentation is: sugar + yeast = alcohol + C02

Sugar levels in grapes has a direct correlation to the level of alcohol in the finished wine. To achieve optimum results, it is not unusual to dilute a wine to lower the sugars in hot climates. In cooler climates, it is not unusual to add sugar to raise the alcohol.

Why is it necessary to make these adjustments? Sometimes it is done in order to meet regulations. Sometimes it just isn’t possible to pick exactly when the grapes are ready. Late season rain will dilute sugars, but picking too early will yield higher acidity and lower sugars. It’s a big crap-shoot, and one of the reasons that farmers are so stressed out around harvest time. It’s never perfect.

Acidity is also affected by the weather. Grapes contain several different types of acid, the main two being malic and tartaric. As the grapes ripen, malic acid reduces. In very hot years, lower acidity could cause the resulting wine to become unstable. If left unbalanced, the wine could easily turn to vinegar.

To lower the pH to a safe level, additions of tartaric acid (C4H6O6) are required to bring it into balance. Although tartaric acid has no adverse effect on the flavor of the wine, it can change the mouth-feel, making it silkier and rounder feeling in the mouth. Not necessarily a bad thing.

Yeasts are often added to promote an efficient fermentation. The faster a fermentation is completed, the more predictable the process is. For mass-produced wines, cultured yeasts are almost always used, as they help to produce a more consistent product from vintage to vintage. Some yeasts will also introduce specific flavors into the resulting wine, and a winemaker may choose to use a particular strain for this reason.

Sulphur is Here to Stay

Sulphur is one of the most controversial elements used in the winemaking process – at least it is for some wine drinkers. There is no way to avoid it. Sulphur is a naturally occurring substance that is a by-product of fermentation. It exists in all grapes, but is also added.

Sulphur is used in the following ways:
•    Added to fresh grapes to prevent oxidation
•    Added to fermenting juice to stabilize color and preserve the longevity of the wine
•    To prevent re-fermentation of the residual sugars
•    Introduced into wine bottles before filling to kill bacteria
•    To preserve corks before bottling

Wines that are un-sulphured will go bad very quickly. Organic wines all have sulphur added, so don’t think that just because it’s organic that you’re going to escape it. like it or not, sulphur is an integral part of the process, and it’s here to stay.

The good news is that there are legal limits, and these limits are well below human taste threshold. Alternatives include sorbate and citric acid (C6H8O7), but these compounds would never be used in a quality wine as they impart unpleasant flavors: sorbate tastes like bubble gum, and citric acid is just far too sharp to affect a pleasant result.

Tannins and Enzymes

Tannins and enzymes are preservatives that are often added to both red and white wines. Tannin naturally occurs in grape skins, seeds and stems, and can be found to a lesser degree in oak barrels. Sometimes added during fermentation to knit together the mouth-feel of a wine, it is common in lower quality or mass-produced wines.

Even high-end wines employ the use of enzymes, however. Pinot Noir, for example, has very thin skin and little pigmentation (hence its light color), so the addition of enzymes serves to prevent fading and discoloration over time. Ultimately, the reasons why enzymes and tannins are added are to fill in the gaps that have been left by challenging vintages.

Oak Flavors

Oak flavors are not always the result of a barrel. In fact, if your wine costs less than $20, you can rest assured it has never seen a barrel. Winemakers can impart oak flavor by adding oak chips to the tank, or granulated oak, which is toasted oak in powdered form. Barrels are expensive. If wine was put into barrel, the retail price would need to go up. Barrel ageing also takes time, and sometimes the winery needs to get the wine finished and onto shelves as quickly as possible. Using chips or granulated oak is one way that they can do that.

Allergy Awareness

For those with allergies or sensitivities to tannins or sulphur, finding a wine that won’t make you sick or give you a headache might be a challenge. It would be easy to say ‘stick to small-production wines that are naturally made’, but it would be impossible to discern these things just from looking at the label.

Instead, keep in mind that mass-produced wines will always have higher levels of chemical additions, tannins and enzymes, as these are the tools with which a winemaker is able to create a consistent product from year to year. That said, a high price tag is no guarantee of avoiding these things. One would hope that in your journey of discovery, you’d at least have some fun along the way.

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About The Author
Astrid Young
Astrid Young
Astrid Young is a certified sommelier and hospitality professional with over thirty years of global experience. Having travelled to - and lived in - many of the world’s hottest (and coolest) wine regions, her expertise and connections to some of the wine industry’s most illustrious characters make for a narrative that reads like a novel, with a healthy and delicious twist of facts, statistics and opinions against the backdrop of wine country shenanigans we’d all like to have. Though she’s well known for her wine acumen, Astrid is also a professional musician and has written a Canadian bestseller. Her passion for foodie culture, drinking great wine and living the good life is infectious, and she loves nothing more than to share what she’s learned, dispelling the myth that wine is some elitist secret only known to a chosen few. Known for her expertise on pairing wine with food, and especially spicy food, she’s created award-winning wine and cocktail programs all over North America. Currently living in Canada’s newest wine region, Prince Edward County, she spends much of her time writing, speaking and consulting on the subject of wine, and how to best enjoy it with all kinds of cuisine.
  • April 25, 2016 at 10:08 pm

    Enzymes are not preservatives…

    Enzymes are proteins that convert one molecule into another. Such as the extracellular Invertase, which converts non fermentable Sucrose into Glucose and Fructose which the yeast can consume.

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