So, why aren't my beers up to snuff, and why do they all share similar flaws? For the same reason that most commercial gluten-free beer isn't any good: they're not made with grains! Like most breweries here in the U.S. that make gluten-free beer, I've been relying on grain extracts and syrups, as well as honey, sugar, and candi syrup (a caramelized sugar product common in Belgian beers). Some of my beers have used "steeping grains"—home-roasted grains steeped in the brewing liquid like a big tea-bag—and while that helps a bit, it doesn't do the job of adding the sort of complex maltiness that most beer-lovers expect.
Okay, I hear you saying, if the extract method sucks, why don't you just use grains? Well, ultimately that is precisely what I intend to do, but it's not quite so simple.
The reason brewing gluten-free beer is hard is because the gluten-bearing grains found in beer—barley, wheat, rye, and oats—have a slew of unique properties that make them perfect for brewing, and these properties are not found to nearly the same extent in gluten-free grains. Specifically, for a grain to be suitable for traditional brewing methods, it needs two things:
- Good Diastatic Enzymes: unmalted grains are mostly starch and protein. When grains are malted ("malting" is just sprouting and then drying at specific temperatures), they produce enzymes, which in the presence of water and heat can turn the starch into sugar that the yeast can then eat and turn into alcohol and carbon dioxide. The quantity and quality of enzymes in a grain determines its diastatic power, "diastasis" meaning the process of breaking down starch into sugar. Traditional brewing grains like wheat and barley and oats have excellent diastatic power, but grains like rice, corn, quinoa, amaranth, buckwheat, and millet are not so good. They can still be used, but they need longer mashing times and are generally less efficient at producing a nice sweet brewing liquid for the yeast to ferment.
- Low Gelatinization (or Hydrolyzation) Temperature: this is probably the biggest problem. Before a starch can be acted upon by the diastatic enzymes, it has to be hydrolyzed—liberated from the grain and made soluble in water. This requires heat, and different grains have different temperatures at which their starches hydrolyze; this is known as their gelatinization temperature. Now, the tricky thing is that the diastatic enzymes mentioned above have an optimal temperature range for doing their job—they work best between 145°F and 153°F. If the temperature gets much higher, the enzymes get destroyed by the heat! Lucky for barley, wheat, and rye, their gelatinization temperatures are just about the same exact range in which the enzymes work their best! Unfortunately, most gluten-free grains are not so lucky, and do not gelatinize until heated above 170°F—just hot enough to denature whatever diastatic enzymes the grain might have.
So, what is a determined gluten-free brewer to do, when all of the grains available are biologically handicapped as far as traditional brewing methods are concerned? My research has shown a few possibilities:
- Decantation (or Decoction) Mashing: basically, this is a more complex version of the typical infusion mash used by most brewers. Instead of simply adding the grain to hot water at the optimal temperature and allowing to rest for about an hour while the enzymes do their work, this procedure involves stepping the grain-water mixture up through a few low-temperature rests, and then decanting off the enzyme-rich liquid, cooking the grains to gelatinize them, and then adding back in the enzyme-rich liquid to (hopefully) convert the now-soluble starches. This is easy enough to do at home, but in a commercial brewery would require lots of specialized equipment.
- Prolonged Mash Schedule: like most things in nature, diastatic power and gelatinization temperature are not hard-and-fast quantities for grains, but represent the peak of the bell-curve. It IS possible to get a portion of the grains to gelatinize at a lower temperature, but it takes a lot longer. Thus it's conceivable that a prolonged mash at the high end of the optimal diastatic range could be effective for some grains.
- Supplementation of Enzymes: Why deal with the poor diastatic power of gluten-free grains and the tug-of-war between optimal gelatinization and optimal diastatic action, when you can just cook the grains, cool them, and add some chemically-isolated enzymes? There are plenty of natural sources of diastatic enzymes, most notably the fungus Aspergillus oryzae, also known as koji and traditionally used in the brewing of saké, and it's possible to buy the isolated enzymes from brewing suppliers. The tricky part is finding the right mix of enzymes—there are several that are important in brewing—and getting them to work consistently.
Option 3 is the one I'm most drawn to as of now, because it allows the use of unmalted grains (although it's possible malted grains will end up with superior flavor, and may still be necessary anyway) and doesn't require a special procedure or special equipment in the commercial brewery, just a sort of "backward" mashing schedule where you start at a high temperature to cook the grains and then drop it through the various enzyme rests.
However, my first few experiments haven't been terribly promising; I did 1-gallon trials of pure instant gluten-free oats as well as roasted buckwheat, and both came out extremely weak and watery. There are many factors that could have caused this, though; for one, I lacked a grain mill to crack the grains, so perhaps got poor starch hydrolysis. For two, I may not have cooked the grains long enough. For three, oats and buckwheat might need a different enzyme mix than what I had. I have lots of further experiments planned, and now that I can see extract is just not going to yield the results I want, my motivation is high.