Most wine is naturally gluten-free and safe to consume on a gluten-free diet.
However, to dive deeper into the answer of whether wine is gluten-free, we must look at the processes of making wine.
Red and white wine is made predominantly from grapes, which are naturally gluten-free. The fermentation process also does not include any gluten. After fermentation, a process called fining, in which substances are added to the wine to help clarify it, could potentially cause gluten contaminants to enter the bottle. During this process, fining agents bind with unwanted particles and debris in wine, which can then be filtered out so the wine appears clearer.
If a winemaker uses gluten or a product containing gluten as a fining agent, the gluten can remain behind in the bottle. For someone with celiac disease or gluten sensitivity, this could potentially be harmful. However, studies suggest that even if there is gluten in the bottle after fining, it is much lower than the 20 parts per million (ppm) which is the maximum amount of gluten a product is allowed to still be labeled gluten-free, based on guidelines set by the FDA.
There has also been discussion about wines aging in oak barrels sealed with wheat paste. Studies have shown that the amount of gluten found in these wines was “below the lower limit of quantification for gluten for these assays of 5 and 10 parts per million, respectively,” according to Gluten-Free Watchdog. Therefore, it can be concluded that wines aged in these types of barrels can still be considered gluten-free.
Despite possible contamination during the fining process or aging in oak barrels sealed with wheat paste, wine is widely considered gluten-free and safe.
Note: Other wine-drinks that may not be safe to drink include wine coolers or “flavored” wine beverages or wine cocktails, which may contain gluten.