Reaching for a bottle of wine to pair with your fave zoodles recipe or lettuce wrap? If you follow a gluten-free diet, it’s a good idea to double check that wine label before you commit.

While most wines are considered gluten-free, some could pick up small amounts of gluten during processing. Here’s what to look for to make sure you’re getting a glass with zero gluten.

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Gluten is a protein that’s found in wheat (and some other grains) that helps food maintain its shape. Wine’s made using grapes, other berries, or fruit (all naturally gluten-free ingredients). But it’s possible for gluten to come into play through cross-contamination during some stages of winemaking.

The earliest stages of winemaking generally don’t involve contact with any gluten products. And even if any gluten managed to sneak its way in during those processes, the fermentation process would kill it. (Fermentation’s when yeast turns juice sugars into alcohol.) But when it comes to later processes, contamination is possible.

Gluten *could* be used as a fining agent

Clarification (aka fining) removes unwanted substances called colloids from the wine to produce a clear product that has a longer shelf life. There’s a small possibility for cross-contamination during this stage. Most of the time, winemakers use gluten-free items (like egg whites, milk protein, or fish protein) when fining, but it’s technically possible to use gluten.

Gluten can leave behind a sediment at the bottom of the bottle, though, so most winemakers avoid it. Plus, even if gluten’s used for fining, research shows that what’s left falls below 20 parts per million or 0.0002 percent. That’s the limit the Food and Drug Administration has set for labeling items gluten-free.

One report also found that even if a gluten-based agent was used as a sealant, very little or no gluten at all could be detected in the wines. Most people with celiac disease are okay with such a tiny amount of gluten, although a small group can still be sensitive to it.

Some wineries could use gluten-contaminated barrels

Cross contamination is also possible during the aging stage. That’s when wine’s stored in barrels, stainless steel or ceramic tanks, or large wooden ovals to allow oxygen to get into it over a period of time. One outdated method of storing wine involved using oak barrels sealed with wheat paste (which contains gluten).

Most wineries today use paraffin wax as a sealant instead, which is naturally gluten-free. They also may use stainless steel barrels that don’t need a sealant. While the risk of contamination from that method is low, it’s still possible.

If you’re looking for a wine that’s totally gluten-free, there are a few ways to shop with confidence.

  • Look for the “gluten-free” label or certification mark. Keep in mind that the FDA doesn’t require all foods that meet the definition of gluten-free be labeled “gluten-free”. The Alcohol and Tobacco Tax and Trade Bureau (TTB) works with the FDA to regulate wine, and states that the gluten-free label can only be on a bottle of wine if it’s made with ingredients that do not contain gluten. Beverages created with grains that have gluten content must be labeled with the terms “treated,” “processed,” or “crafted” to remove gluten.
  • Avoid possible hidden ingredients. Wineries can include more than 60 ingredients in their wine that they don’t have to disclose. This can include artificial colors, flavors, stabilizers, preservatives, and sulfites. If you’re concerned, try to buy organic or natural wines that are made without additives.
  • Talk with the winery. Find out who produced the wine and start asking questions. You can ask about what kind of sealants or storage they use for the aging process, and how their fining process works.

Because of the distillation process, most distilled liquors are gluten-free. Gin and mixed drinks can be tricky since there’s a possibility they might contain gluten. If you’re looking for something alcoholic, some gluten-free drinks to try include:

  • Tequila. Look for 100 percent blue agave tequila, which is naturally gluten-free.
  • Pure rum. While flavored or spiced rums may contain gluten, plain rum is gluten-free.
  • Gluten-free hard cider. If you want something sweet, opt for hard cider that’s labeled gluten-free. It’s typically naturally gluten-free, but it’s possible (although rare) for gluten to sneak in there through cross-contamination.
  • Vodka. Any vodka distilled from potatoes, gluten-free grains, or gluten-free ingredients is safe to drink.

Since it’s rare for wine to include gluten, if you’re experiencing icky symptoms after drinking wine, it’s possible that there’s something else going on.

  • Gut inflammation. Alcohol, including wine, can increase gut inflammation. People who have inflammatory bowel disease (IBD), like Crohn’s disease and ulcerative colitis, may not feel well after drinking wine.
  • Histamine and tyramine. These are byproducts of the fermentation process and can sometimes cause headaches and stomach problems. Red wine can contain more histamine than white wine.
  • Tannins. This is a plant compound that can trigger headaches. You’ll usually find more of these in red wine.
  • Sulfites. Sulfites can be added to both red and white wines as a preservative and can trigger asthma and headaches.
  • Bacterial overgrowth. Even one glass of wine might lead to small intestine bacterial overgrowth (SIBO), which can cause bloating, gas, abdominal pain, diarrhea, and constipation. The American College of Gastroenterology has linked moderate drinking to SIBO.

Wine’s generally considered gluten-free and it’s rare for the finished product to contain enough gluten to affect someone with celiac disease. However, there’s still a very small chance that gluten could end up in wine during processing.

Looking for a glass of vino that’s for sure gluten-free? Checking with the manufacturer directly is your best bet.