Wine is often the alcoholic beverage of choice for those with celiac disease and gluten sensitivities. For them, ingesting gluten can be a serious health hazard. Wine, made of grapes and yeast, has always been assumed to be gluten free. But in the last several years information on certain barreling and fining techniques in the winemaking process have brought that assumption into question.
The problem. Until recently the assumption has been that since wine is made solely from grapes and yeast, both gluten-free ingredients, wine is also gluten free. It has been the beverage of choice for those suffering from celiac disease and other gluten sensitivities because so many other grain-based alcoholic beverages have become forbidden. It has been brought to light that some wineries age both red and white wines (particularly wines at or above the price point of $12/bottle) in barrels made from white oak staves. In the past, it was common cooperage practice to use wheat paste to seal the barrelhead to prevent leaking. This introduces a possible point of gluten contamination into the wines aged in these barrels. The second possible point of gluten contamination comes during the fining process in which wine is clarified. In a (now nearly obsolete) practice of fining,1 gluten was introduced into wines as a fining agent, acting as a protein that captured impurities and dragged them to the bottom to be extracted from the wine.
The research. In a test published on "The Gluten Free Dietician" website,2 two types of wine aged in barrels, a cabernet sauvignon and a merlot, were tested in two batches by two different ELISA tests. Each test revealed that gluten in both wines was less than 5 ppm (parts per million), and 5 ppm is the smallest amount of gluten that can be detected with current technology and is far below the < 20 ppm at which the FDA considers a food to be gluten free.4 Also, in 2012 the Tobacco, Tax, and Trade Bureau (TTB) released a stopgap policy on the gluten free labeling of alcoholic beverages. This ruling disallows gluten free labeling of alcoholic beverages that use wheat, rye, barley or crossbred varieties of these grains as the originating ingredient. This Interim Policy also informs that beverages that use any of the previously mentioned grains, as well as additives or storage materials that contain gluten, may not be labeled gluten free.5 6
The results. In modern cooperage, paraffin wax is generally used in place of wheat paste for barrel sealing.7 It is very uncommon, especially in the United States, for wheat/gluten to be used as a fining agent. Most fining agents (if used at all) prove to be different varieties of animal proteins.8
In the final analysis, the amounts of gluten found in wines aged in barrels were less than what is actually measurable by ELISA tests, and very few (if any) wineries use wheat/gluten as a fining agent. Sufferers from celiac disease or other gluten sensitivities can be confident that American wines are not a hidden gluten danger. But as with all health issues, it is up to the consumer to do the research and make an informed decision based upon those findings.
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Endnotes:
1 http://telayawine.com/2014/wine-gluten-free/
2 http://www.glutenfreedietitian.com/gluten-content-of-wine-aged-in-oak-barrels-sealed-with-wheat-paste/
3 http://www.glutenfreedietitian.com/gluten-content-of-wine-aged-in-oak-barrels-sealed-with-wheat-paste/
4 http://www.winespectator.com/webfeature/show/id/48789
5 http://www.glutenfreedietitian.com/gluten-content-of-wine-aged-in-oak-barrels-sealed-with-wheat-paste/
6 http://www.ttb.gov/rulings/2012-2.pdf
7 http://winemakermag.com/941-can-you-tell-me-if-typical-wines-in-the-store-contain-gluten-or-if-certain-yeasts-contain-gluten
8 http://www.winespectator.com/webfeature/show/id/48789