We are completely gluten-free in our cooking and I am always concerned about the safety as well as the quality of the food we serve. I have celiac, and my son was a severely celiac child, so I know the consequences of not eating safely. One of our patrons recently raised their own concerns in describing their reactions to distilled white vinegar, and this spurred me to renew my research and now to share with you my conclusions.
First, I reviewed the general health postings starting with guidelines from the University of Chicago Celiac Disease Center and other medical sources. In general, they state that the distillation process makes distilled white vinegar safe. In general, they warned that the vinegar to stay away from if you are celiac is the malt vinegar, as it is not distilled and possibly has additives that could have gluten. (www.celiacdisease.org).
The USDA’s definition of gluten-free is that a product has less than 20 parts per million gluten, which is a threshold defined by the limits of the instrumentation used to test the amount of gluten in a product or ingredient (typically the ELISA analytical immunoassay testing for detecting the presence of a substance). It’s important to remember that testing cannot be practically measured beyond the point of 20 parts per million, so that’s where the USDA has drawn the line on what can or can’t be called gluten free.
Vinegar is made from anything containing sugar (or starch, which can then be converted into sugar by way of either temperature or enzymatic breakdown) as the starter. These starters can range from fruits, grains, roots and even cellulose or wood products. Although is can be made directly from sugar, it is usually the practice to convert sugar into alcohol and then alcohol into vinegar.
US Food and Drug has split vinegar into the following categories:
- Vinegar, cider vinegar, and apple vinegar made from apple juice
- Wine vinegar, grape vinegar made from grapes
- Malt vinegar made from barley
- Spirit vinegar, distilled vinegar and grain vinegars from dilute or distilled alcohol.
As stated earlier, vinegars also come from many other starters such as rice and coconut that is more common in Asia.
Vinegar mainly consists of acetic acid and water. This is formed from the acidification of alcohol, where sugars convert to alcohol with fermentation -often using brewers yeast (saccharomyces) or other starter bacteria. This becomes the vinegar stock (as produced by fermentation of ethanol by a starter bacteria). The bacteria for making the stock can often be found in the source material itself, such as the natural bacteria on the grape skins.
As a second step, the distillation of vinegar separates the pure ethanol from all other later non-volatile material. This is done by applying heat to volatize particles, and capturing them separately typically through surfaces (tubes) that collect and transport the material into another vessel through condensation. Once cooled, the condensation contains the material you want… vinegar. The important thing to note is that gluten peptides that survived fermentation cannot not survive in the distilled product.
Gluten itself is a large molecule held together by amino acids. These amino acids can sequence together into good things for you (such as L-glutamine, which is the amino acid that heals damaged tissue) and bad things (such as gliadin, which is the cause of many intestinal autoimmune responses such as Celiac disease.) Alkalis hydrolyze gliadin and break them down into amide and peptide bindings in a continuous process, not unlike enzymatic hydrolysis. These peptides again do not survive to transfer into the final distilled product.
My recommendation – read labels to make sure there are no additives added in after distillation that contain gluten. Always read labels and stay away from Malt vinegars, which likely do contain glutens!
That said, I do believe that we as a community should continue to push for labels to clearly indicate the starter original source for the vinegar, and list all the additives and their sources that are included in the product. Knowing how your food is made and what goes into it is important to everyone – not just the people that are celiac.
Of course, at The Curious Fork, we care a great deal – whether you eat our food, or come to our classes and learn to make the food yourself, we would celebrate your interest and always stay curious!