The stuff that we call Gluten is actually 2 proteins – gliadin and glutelin. Gluten is the stuff that gives fresh baked bread its wonderful elasticity. But, Gluten can also attack the lining of the small intestine causing nausea-like symptoms in some people.
In theory, any distillate coming off a still should be gluten free because the gliadin and glutelin molecules are of such a size and of such a low vapor pressure that they should not be able to travel through the distillation columns in a distillery operation.
So why then do some gluten-sensitive people claim that certain Vodkas cause them to feel ill? This is a question that the scientific community is grappling with. In our 5-Day Distilling Workshops we have had a number of Celliac sufferers who have made themselves ill by sampling Vodkas – so I have seen this phenomenon in real time. Evidently, some small bits of gliadin or glutelin are managing to get through the distillation process by hitching a ride on the back of an ethanol molecule. But how? And why do only some Vodkas present a problem to Celliac sufferers?
Gluten content in distilled alcohol is measured by the ELISA Test ( Enzyme-Linked Immuno-Sorbent Assay). In this test, a sample of the solution (ie Vodka) to be tested is exposed to an enzyme which causes a color change in the solution being tested. The extent of the color change is proportional to the amount if gluten present. The problem is, this test is generally regarded by authorities ( ie Canada Food Inspection Agency) to be inaccurate. Hence, in Canada it is the duty of the alcohol maker to ensure his product does not pose a health risk to people. In other words, label your Vodka gluten free, but be sure to tell each and every purchaser that there still is a chance for them to have an adverse reaction if they are a Celliac sufferer. Apparently about 10% of Celliac sufferers will experience a reaction if they consume even tiny amounts of gluten. In the USA, the TTB states that in order to be gluten free, a spirit must have less than 20 ppm gluten. But, with the ELISA test being subject to inaccuracy, it is not possible for a distiller to know with certainty what his gluten levels are.
To this end, there is now something called the R5 competitive ELISA test being advanced as a more accurate way of determining gluten. Apparently the R5 test can detect down to 3 ppm gluten.
So, if you are a Celliac sufferer, and you are shopping around for craft distilled products and find some that are labelled gluten free, just remember, that claim of gluten free has not been ELISA test verified. You may experience an adverse reaction. Sample the spirit in small quantity. If you do not encounter symptoms, then that spirit is one for you. If you do feel poorly, then that spirit is not the one for you.