Gluten is a protein found in wheat, rye, and barley that those with celiac disease or an intolerance to gluten must be careful to avoid.

Figuring out if wine is gluten-free can be tricky since the United States and many other countries don’t require ingredient lists on its labels (1, 2).

Though wine is naturally gluten-free, winemakers may use processes that add gluten to the finished product.

This article explains how wine is made and factors that may affect its gluten-free status.

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Wine is usually made from grapes or sometimes other fruits like berries and plums — all of which are naturally gluten-free ().

Here’s the basic wine-making process for grape-based varieties (1, 4):

  1. Crushing and pressing. This extracts the juice from the grapes. When making white wine, the juice is quickly separated from the grape skins to avoid color and flavor transfer. When making red wine, color and flavor are desirable.
  2. Fermentation. Yeast, which is gluten-free, converts juice sugars to alcohol. Sparkling wine undergoes a second fermentation process to make it bubbly. Fortified wine like sherry contains distilled alcohol, which is also gluten-free.
  3. Clarification. This makes wine clear rather than cloudy. The most common method to achieve this is fining, which involves using another substance to bind and remove unwanted elements. Various fining agents can be used.
  4. Aging and storage. Wine may be aged in stainless steel tanks, oak barrels, or other containers before bottling it. Stabilizing agents and preservatives, including sulfur dioxide, may be added but are typically gluten-free.

While wine ingredients are gluten-free, contamination with gluten may be possible during processing and storage.

Summary Wine is made from grapes and sometimes other fruits, which are naturally gluten-free. However, there are concerns about the potential for gluten contamination during processing and storage.

Fining is a process that removes unwanted elements, such as proteins, plant compounds, and yeast, to ensure wine is clear rather than cloudy and smells and tastes good (1).

Fining agents bind to unwanted elements, which then drop to the bottom of the wine and can easily be filtered out.

Egg whites, milk protein, and fish protein are common fining agents that all happen to be gluten-free. Vegan varieties use vegan-friendly fining agents, such as bentonite clay (1).

Gluten itself can be used for fining, but it’s rare. When used as a fining agent, gluten largely remains behind as sediment at the bottom of the storage container when the wine is filtered and transferred to bottles.

Studies suggest that the remaining gluten after fining falls below 20 parts per million (ppm) or 0.002% — the limit set by the Food and Drug Administration (FDA) for labeling items gluten-free (5, 6, 7, 8).

However, a small subset of people with celiac disease is sensitive to trace amounts of gluten below 20 ppm. If you fall into this category, ask the winery what they use for fining or purchase certified gluten-free brands (9, 10).

Most wine sold in the United States is regulated by the Alcohol and Tobacco Tax and Trade Bureau (TTB). Varieties that contain less than 7% alcohol by volume are regulated by the FDA (11).

The TTB only allows gluten-free labeling if no ingredients containing gluten are used and care is taken to avoid cross-contamination with gluten during alcohol production (12).

Summary Common fining agents include egg, milk, and fish proteins, as well as bentonite clay. Occasionally gluten is used for fining, and tiny amounts may remain after filtering.

Wine can be held in various types of containers during aging and storage, though stainless steel has become one of the most popular (1).

An older, less common practice is to store it in oak barrels and seal the top with a small amount of wheat paste — which contains gluten. Still, the risk of significant contamination from this is low.

For example, when the Gluten Free Watchdog agency measured gluten concentrations in two different wines that had been aged in wheat-paste sealed barrels, they contained less than 10 ppm of gluten — much less than the FDA limit for gluten-free items.

It’s now more common to seal the barrels with paraffin wax. However, to be certain what a winery uses for their sealant, contact them.

Summary Wine can be held in various types of containers during aging, though stainless steel is one of the most popular. Less frequently, it’s stored in oak barrels sealed with wheat paste, but gluten contamination from this method is usually minimal.

Wine cooler drinks first gained popularity in the 1980s. In the past, they were made with a small percentage of wine mixed with fruit juice, a carbonated beverage, and sugar. They were generally gluten-free.

However, after a major tax increase on wine in the United States in 1991, most wine coolers were reformulated as sweet, fruity malt beverages. Malt is made from barley, a gluten-containing grain ().

These fruity drinks are labeled malt coolers or malt beverages but could be mistaken for wine coolers. These beverages contain gluten and should be avoided by those with celiac disease or gluten intolerance (14).

Summary Fruity drinks called wine coolers have largely been reformulated as malt coolers made from barley, a gluten-containing grain. You should avoid malt beverages on a gluten-free diet.

If you avoid gluten and have experienced headaches, digestive upset, or other symptoms after drinking wine, reasons other than gluten contamination may be to blame:

  • Expanding blood vessels. Drinking alcohol causes blood vessels to expand, which stretches the nerve fibers wrapped around them. When this happens in your brain, it can trigger headaches (15).
  • Inflammation. Alcohol may increase gut inflammation, particularly in people with inflammatory bowel diseases (IBD), including Crohn’s disease and ulcerative colitis. Some people with celiac disease also have IBD (16, , 18).
  • Histamine and tyramine. Some people are sensitive to these byproducts of fermentation, which may trigger headaches and digestive upset. Red wine may contain up to 200 times more histamine than white wine (15, 19, , 21).
  • Tannins. Wine contains certain plant compounds, including tannins and other flavonoids, that may trigger headaches. Red wine typically contains more than 20 times the flavonoids of white wine (15, 22).
  • Sulfites. These may be added as a preservative to both red and white wines but must be declared on the label if totaling 10 ppm or more. Sulfites are compounds that can trigger asthma and possibly headaches (1, 22, 23).
  • Allergens. Some fining agents come from allergens like milk, eggs, and fish. It’s unlikely that enough remains to cause a reaction, but processing varies. Wine labels don’t have to disclose allergens like foods do (1, 24, , 26).
Summary Wine contains many compounds other than gluten that can trigger headaches and digestive system upset in sensitive individuals.

Wine is naturally gluten-free, but some practices — including using gluten during the fining process and aging it in oak barrels sealed with wheat paste — may add tiny amounts of gluten.

If you’re sensitive to traces of gluten, ask the winery how their products are made or purchase certified gluten-free varieties.