Yes, Guinness contains gluten. It is brewed with malted barley, one of the three primary gluten-containing grains (alongside wheat and rye). Guinness is not labeled gluten-free, and Diageo, the company that owns the brand, lists it among its non-gluten-free beers.
Why Guinness Contains Gluten
The core ingredients in Guinness are roasted malted barley, hops, yeast, and water. That roasted barley is what gives Guinness its deep color and distinctive bitter-coffee flavor, but it’s also the source of gluten. Barley contains proteins called hordeins, which belong to the gluten family and trigger immune responses in people with celiac disease or gluten sensitivity.
Brewing does break down some of the proteins in barley during fermentation, which is why finished beer generally contains less gluten than raw barley flour. But “less” is not “none.” The FDA sets the threshold for a gluten-free label at below 20 parts per million (ppm). Guinness, brewed directly from a gluten-containing grain, does not qualify for that label.
How Different Guinness Varieties Compare
Guinness comes in several forms, including Draught, Extra Stout, and Foreign Extra Stout. All are brewed with barley, so none are gluten-free. However, the gluten levels vary between them. Independent testing from gluten-tracking communities has found that Guinness Draught tends to measure lower in gluten than Guinness Extra Stout, with some tests reporting Draught at under 5 ppm. Extra Stout, being a heavier, more concentrated beer, typically tests higher.
This difference sometimes leads people to claim Guinness Draught is “safe” for gluten-sensitive individuals. That’s a misleading conclusion. A single low test result doesn’t guarantee consistency across batches, and the testing methods used for fermented products have known limitations. The Celiac Disease Foundation has noted that current gluten testing is not sufficiently reliable for fermented or hydrolyzed products, because the process of breaking gluten into smaller fragments can cause standard tests to undercount the actual amount present.
Why “Low Gluten” Isn’t the Same as Gluten-Free
Some beers are marketed as “gluten-removed,” meaning they start with barley or wheat and then undergo enzymatic treatment to break down gluten proteins. Guinness does not use this process, but even beers that do aren’t considered safe for people with celiac disease. Research supported by the Celiac Disease Foundation found that protein fragments can remain in gluten-removed beers that still provoke an immune reaction, even when standard tests show low ppm readings.
The core problem is that breaking gluten into smaller pieces doesn’t necessarily make it harmless. It just makes it harder to detect. This is why the FDA requires gluten-free beers to be made from inherently gluten-free grains like sorghum, rice, millet, or buckwheat, rather than from barley that’s been treated after the fact.
Gluten-Free Alternatives to Guinness
If you love dark beers but need to avoid gluten, you won’t find a gluten-free version of Guinness itself. Diageo has not released or announced one. Your options fall into two categories:
- Dedicated gluten-free stouts: Several craft breweries produce stouts and porters using sorghum, buckwheat, or millet as the base grain. These are brewed without any gluten-containing ingredients from the start. Brands vary by region, but look for beers explicitly labeled “gluten-free” rather than “gluten-removed” or “crafted to remove gluten.”
- Gluten-free dark ales: Some gluten-free breweries make dark ales that approximate the roasted, slightly bitter profile of a stout without using barley. They won’t taste exactly like Guinness, but they’re the closest safe alternative.
The Bottom Line for Sensitive Drinkers
Guinness is made from barley. It contains gluten. Some versions may test lower than others, but no version is certified gluten-free, and the testing methods for fermented drinks aren’t reliable enough to guarantee safety. If you have celiac disease, even a beer that tests below 20 ppm in one batch could contain reactive protein fragments that the test missed. For people with non-celiac gluten sensitivity, the risk is less clear-cut, and some individuals report tolerating Guinness Draught without symptoms. That’s a personal call, but it’s worth knowing the testing limitations before making it.