What’s Really in Your Wine?

Staff Reports

Luxuriating with a nice glass of wine at any time of the day is one of the life’s simple pleasures. But what’s actually in that glass is not so simple — especially these days. The reality is that consuming wine is much more complex than just enjoying fermented grape juice. 

At its core, wine is made of fermented grape juice. The primary components include juice, alcohol (mostly ethanol), acids (like tartaric and malic acid), sugars (if not fully fermented), and a complex mix of flavor compounds known as polyphenols. These natural elements each give wine its character, from fruitiness and spice to tannins and acidity.

While winemaking is deeply rooted in tradition, modern producers often rely on a range of additives to ensure their wines are consistent in flavor, color and clarity. Some of these are entirely natural, while others may surprise even seasoned wine drinkers. Even wines labeled as “natural” or “organic” can contain some of these additives, although in lower amounts or with stricter regulations. 

While not all additives are harmful or artificial, being informed helps you choose wines that align with your taste and values. But it begs the question: why are things added to wine?

A Look at Common Elements and Additives

The journey from grape-to-glass can be unpredictable. Factors like weather, soil and grape ripeness all influence the final product. To manage this variability, winemakers can legally use dozens of additives—many of which are not required to be listed on the label. 

Sulfur dioxide is perhaps the most widely known additive. It is used to prevent oxidation and bacterial spoilage. Though naturally produced during fermentation, winemakers often add extra sulfites to ensure stability, especially in wines intended for long-term aging or export.

For example, in order to stabilize the color and enhance mouthfeel, some winemakers might choose to add mega purple, a grape concentrate that intensifies the hue and flavor in red wines. While it’s derived from grapes, its use is often associated with mass-market wines seeking a consistent, bold appearance and style. However, that consistent style has also been demanded, if not expected, from many consumers. 

Then another common additive is oak flavoring. It is used to mimic the effects of aging in oak barrels. This can come in the form of oak chips or staves, allowing producers to impart a signature vanilla and spice character without the time and cost of traditional barrel aging.

When the acid is not quite where it should be, winemakers may add tartaric acid or malic acid, especially if the grapes come from warmer climates where acidity naturally drops. And then to lower it, some producers might use calcium carbonate, CaCO3/chalk, to reduce overly sharp acidity.

Consumers have also become accustomed to enjoying clear, pristine glasses of wine that are free from sediment left over from the grape skins, stems or seeds. To achieve that appearance, winemakers clarify the wine using fining agents like egg whites, bentonite clay or gelatin. Those tools helps filter the wine by binding to unwanted particles. Yes, you read that correctly. Historically in winemaking, animal byproducts were used to filter and fine wines to remove particles from floating around the bottle and glass. For wine lovers who are also vegan, they might want to opt for vegan-friendly wines which are often listed on the back label of the bottle. Bentonite clay and other agents are used to filter vegan-friendly wines. Though these are typically removed before bottling, they are still part of the production process.

Of course, there is the overarching concern of what’s on or around the grapes. The Industrial Agricultural Revolution in the 1900s saw the increasing use of chemicals to enhance yields and manage pests, which we have since learned can have negative impacts on consumer health. Therefore, many consumers are also opting to avoid those chemicals that might make their way into wines by opting for wines that stray away from using synthetic inputs like pesticides, herbicides and fungicides.

Gluten?

And then there is always an unexpected wildcard: gluten. Wine is naturally gluten free because it is made from grapes. However, use of oak barrels in which paste from wheat flower is used as a traditional sealant for barrel heads could impart some gluten into the wine. The trace amounts of gluten tend to be pretty low, less than 20 parts per million, but those with celiac disease should be aware of the risks.

If you’re looking for 100 percent gluten-free wines, the best option is to research and find wineries that test and certify their wines are gluten-free. The second-best option is to shop for natural, organic and stainless steel-aged wines that avoid potential cross-contamination from barrels or additives. There could also be gluten found in wine coolers and flavored wines, also known as “wine products.”

Whether you suffer from health issues, are generally very health conscious or just want wine with fewer additives, focus on natural, organic, biodynamic, and low-intervention wines. These wines typically avoid synthetic chemicals, excessive fining agents, and artificial flavor enhancers