OUR FIRST EVER DISCLAIMER!
This is an article containing information on gluten in the brewing process. This is offered as information only. I am not a medical doctor, nor do I know anything about your medical condition. I am not offering you medical advice, nor should you take this as medical advice. If you have celiacs disease or some form of gluten intolerance, follow the advice of your doctor.
Gluten is a term for a collection of proteins found in wheat (including spelt), barley and rye. Triticale — a hybrid of wheat and rye — also contains gluten. All grains contain proteins similar to gluten, even “gluten-free” grains. However, the proteins from these grains do not seem to affect people with gluten intolerance. Grains commonly listed as gluten-free include rice, corn, sorghum, quinoa, millet, buckwheat, teff and amaranth. Oats are gluten-free, but are frequently processed in facilities (silos, mills) that also handle barley or wheat, so they are frequently cross-contaminated with gluten.
Glutenin, Hordein and Gliadins
In wheat, gluten is composed of glutenin and gliadins. Glutenin is responsible for 47% of the protein content of wheat, which is usually around 14% of the dry weight. In barley, gluten is composed of hordein and gliadins. Total protein in most malting barley varieties is 12% or less. (The protein content is higher in feed barlies.) Gliadens are a class of proteins, of which there are three major types. Gliadins are soluble in water, while glutenin and hordein are not. (Hordein is soluble in strongly alkaline solutions.) In wheat, the amount and elasticity of gluten allows rising breads to be made from it. These breads cannot be made from the other gluten-containing grains, barley and rye, nor gluten-free grains.
Hordein in Barley and Brewing
As barley is the most abundant grain in most beers, let’s look at the fate of barley gluten from farm to fermenter. Hordein and barley gliadens are found interspersed with the starch in a barley kernel. These proteins are storage proteins and their percentage increases as the overall protein content of the grain increases. In fact, the percentage of hordein increases more quickly than that of other proteins (such as albumin) as overall protein levels rise. In malting, protein levels decrease and, as such, so do the levels of hordein. In modern malting, protein modification is one of the major goals as most commercial brewers do not employ a protein rest in their mash regime.
When the wort is run off from the grain bed, much of the hordein is left behind as it is not soluble. Some is carried along by the movement of the wort. Gliadins are soluble and will end up in the wort. During the boil, proteins are coagulated and many sediment with the trub and do not make it to the fermenter. Protein fining agents (such as Irish moss) reduce the amount of soluble proteins. So, fining for proteins would have no effect on hordein (or glutenin, if present) levels. However, if gliadins were positively charged at the pH of wort (information that I have not been able to locate) it would reduce their levels. (Irish moss is negatively charged at typical wort pH levels and attracts positively charged molecules.)
Gluten in Beer
Beer made from barley, or wheat and barley, is not gluten-free. Although the gluten content is reduced during malting, mashing and boiling, finished beer still contains protein. The fact that some beers exhibit chill haze is proof of that. And, some percentage of that will be from the soluble gliadens. In addition, even though it’s insoluble, some amount of hordein probably gets carried over into the finished beer. Although not gluten-free, a glass of beer would certainly have less gluten in it than the grains required to brew that beer.
A group of Swedish scientists published a study of gluten levels in a variety of European beers and found levels from below 10 mg/L to levels around 50 ppm. Beer brewed with wheat and stronger beers tended to have more gluten while beers brewed with gluten-free adjuncts (in addition to barley) and lower strength beers tended to have less. Beers brewed with gluten-free grains (sorghum) had less than 10 mg/L of gluten.
So, if you have celiacs disease or some other form of gluten intolerance, the bad news is that beers brewed from barley — or wheat and barley, or rye and barley— contain gluten. To brew beer that is gluten-free, you would have to use gluten-free ingredients. Possible ingredients include sorghum syrup, rice syrup, brewers corn syrup, apple juice, pear juice, grape juice, honey and pretty much any sugar source that does not come from glutenous cereal grains. Mead, cider, perry, sake and wine can all be made in a gluten-free manner.
Unfortunately, if you want to brew a beer from gluten-free grains (for example, sorghum), you will likely have to malt the grains yourself. (Sorghum is used to make beer in Africa, so you might get lucky and be able to find sorghum malt if you really hunt.)
Hops do not contain gluten, so you don’t have to worry about using them in your gluten-free creations. However, liquid yeast is raised in media containing gluten, although Wyeast and White Labs occasionally release gluten-free versions of various yeast strains. Likewise, dried yeast is generally gluten-free (and these days is frequently labelled as such) as dried yeast producers raise their yeast in a molasses-based media.
For people with extreme forms of celiac disease, beer brewed with gluten-free ingredients, but brewed on equipment used to brew regular beers, might trigger a reaction. If anyone with celiacs disease visits your house, be very careful serving them any alcoholic beverage (or even soda) made with your beer equipment. Likewise, if you store your gluten-free ingredients near your barley or wheat — and especially if you mill your grain in that area — you can contaminate your gluten-free ingredients.
Knight on a White (Labs) Horse?
Interestingly, White Labs produces a product called Clarity Ferm that they claim reduces chill haze and renders beers made with barley or wheat to under 20 ppm gluten. They also offer beer testing for gluten levels.
What if you didn’t have a medical-condition related to gluten, but wanted to reduce the amount of gluten in your beers? (Note: those fad diets that demonize gluten are not backed up by any credible science. If your doctor says you can have gluten, you can have gluten.)
Reducing the amount of gluten in a beer would not be difficult. Obviously, if you have wheat malt in the recipe, replacing that with barley malt would be a start. And of course unmalted wheat has even more protein than malted wheat, so get rid of that. Likewise, substituting gluten-free adjuncts (rice, corn, processed sugar, honey) for part of the fermentables would lower the gluten levels by dilution.
A hard, rolling boil coagulates proteins, so extending the boil from 60 to 90 minutes might help to a small degree. Likewise, increasing the dosage of protein fining agents (Irish moss, whirlfloc) might also help, but potentially at the expense of foam.
Weaker beers, made from less grain, would obviously have correspondingly lower gluten levels.
All-grain brewers may think to themselves, what if I perform a protein rest? This might help to a small degree, but these days most protein modification gets done by the maltster and the protein-degrading enzymes in malted barley are mostly destroyed in the kiln. If you used a very lightly-kilned base malt and performed a long protein rest (30 minutes or more), you might reduce gluten levels a bit, but likely at the expense of foam production and retention.
If you malt your own grains, you could manipulate your protein levels, but that’s beyond the scope of this article. Also, over-modifying barley malt would likely have some negative brewing consequences.
Gluten is in the news frequently these days, both because of legitimate medical conditions associated with it and fad diets that demonize it. An educated brewer can manipulate gluten levels in his (or her) beer or produce fermented beverages from gluten-free ingredients if needed. If you suspect you have a problem with gluten, your first course of action should be to see a doctor. Live to brew in a good health another day.