Gluten is a troublesome protein found in cereal grains such as barley, wheat, and rye. Approximately 1% of the world population is affected by celiac disease which is an autoimmune disorder that damages the small intestine and affects nutrient absorption. Gluten sensitivity is a recognised condition affecting about 6% of the US population, and involves other, less serious reactions from ingested gluten. Since the primary source of sugar in brewing comes from cereal grains, most people with celiac disease and gluten intolerances avoid beer altogether, but craft brewers have gotten creative over the years in trying to offer gluten-free options that still taste great. This post will introduce you to the basics of gluten-free brewing.

Gluten-Free vs. Gluten-Reduced

First, let's go over some definitions since there are some beers labeled as "gluten-free" and some that are "gluten-reduced". The only way to produce a beer without gluten is to not use any ingredients that contain, or have come into contact with, gluten. These beers are labeled "gluten-free" and most would say that they are obviously different from normal beer. The other approach is to brew a beer using normal ingredients and process it to remove the gluten to an "acceptable" level (less than 20 parts per million (ppm) according to the FDA). These "gluten-reduced" beers typically taste much better (more beer-like) than their gluten-free counterparts. This is done primarily using brewer's enzymes such as Clarex, which are typically used to remove chill-haze forming proteins. The remaining gluten content is usually verified using a test called enzyme-linked immunosorbent assay (ELISA) which detects hordein, a barley-derived gluten protein. Depending on the country and their labelling requirements, these beers may be sold as "gluten-free" or as "gluten-reduced" products. Celiacs should take caution, however, since there have been studies that have cast light on the unreliability of the ELISA test compared with the more complex (read "expensive") tests involving mass spectrometry. This means that a product sold as "gluten-free" in one country may actually be "gluten-reduced" to a level that cannot be verified with certainty by the current available tests. True gluten-free brewers in the USA have pushed to require more strict labelling laws to inform consumers of this limitation.

Ingredients

When brewing gluten-free the only sure-fire way is to only brew with non-gluten ingredients. Hops and water are totally safe (no surprise there), but you actually do have to be careful when selecting yeast. But first, let's have a look at common gluten-free grains that are available...

Malt

Just like there are malted and unmalted barley and wheat, there are also gluten-free grains that may be malted or not. Unfortunately the selection may be limited for malted grains so you may consider making your own malt (outside of the realm of this post). Some of these are also available in extract form, such as sorghum (LME).

Millet - While this grain typically shows up in bird feeders, it can also serve as a nice base malt. It is often used as a substitute for wheat in brewing and it has excellent enzymatic strength which comes in handy if you are mashing with other adjuncts. Malted versions include pale base malt, dark, and crystal malt.

Sorghum - A popular pale malt available in liquid form from Briess. It imparts a slightly fruity flavor and aroma and typically contributes a slight sourness.

Buckwheat - Pale and roasted versions available. Contributes a strong, distinctive flavor which can be tart or wheat-like. Roasted versions can add a nutty character. Buckwheat is also high in protein which can be good for head retention.

Maize - Hey, if it's good enough for Miller then why not for gluten-free?

Rice - If it's good enough for Budweiser..... There are plenty of rice-syrups or you could go with rice flakes/white rice to lighten the flavor. Brown rice is to be avoided due to some unpleasant characteristic flavor.

Quinoa - Technically a seed, but may serve as an earthy, sweet substitute for oats.

GF Oats - Oats don't naturally contain gluten but they become contaminated in factories that also process other cereal grains. You have to specifically purchase GF oats which ensure that they have been processed separately.

Others - There are plenty of other GF ingredients that can be used along with the above list for your gluten-free recipes. These include: cassava, soy, potato, tapioca, beans, arrowroot, amaranth, teff, flax, chia, yucca, and nut-flours

Yeast

If you use liquid yeast, many of the manufacturers actually propagate the yeast in a barley-based wort, which excludes it from being gluten-free. To be safe, go with a dry yeast from brands such as Lallemand or Danstar which have certified gluten-free products (typically grown in molasses)

Enzyme

If you wanted to go the "gluten-reduced" rout then you could always brew your normal beer and add a vial of White Labs WLN4000 Clarity Ferm which is designed to eliminate chill haze polypeptides but has the added bonus of significantly reducing gluten from barley and wheat.

Process

All-Extract

The easiest approach to brewing gluten-free is to use sorghum liquid malt extract (LME). You can make a very clear, pale yellow beer with decent head retention using this stuff. In fact, it's the only method that I have tried and I've had decent results brewing pale ales. It works just like any other LME that's out there. I used 2 litres of LME for a 6-gallon batch to achieve an original gravity of approximately 1.060.

Sorghum is the only liquid malt extract available for GF beers. It definitely gets messy, but it makes the brew day much faster! Two liters of this stuff will be enough extract for a 5-6 gallon batch (18-22 litres).

Partial Mash

If you are going to steep some grains for a partial mash method, mill your grains (millet, buckwheat malt or rice malt) and combine with 20-25% rice hulls which will aid with the run-off. Steep them in a nylon steeping bag along with some additional alpha-amylase enzymes for conversion. This is the other downside to using gluten-free grains - some of them lack the enzymes needed for full starch conversion. Liquid and dry forms of the enzymes are available. After steeping you'll want to conduct a mini-sparge by rinsing the grain bag.

All-Grain

As with the previous method you'll want to add rice hulls (20%). A single-infusion mash between 65-74 degrees (C) for 90-120 minutes (or longer for rice malt) should be sufficient.

Andrew Lavery has shared a detailed mash regime as follows:

beta glucan rest @40 C x 25 min
protein rest @55 C x 25 min
decant clear liquid from top of mash and transfer to refrigerator (this contains enzymes required for saccharification)
heat mash to 70 C x 20 min, then bring to boil x 5 min
cool down to 70 C and add cold, decanted liquid to bring it down to 65 C
hold at 65 C x 90 minutes

The reason for all of the nonsense above is that the gelatinisation temperatures for some gluten-free grains (i.e. rice) is often higher than the saccharification temperature. Therefore, you remove the enzyme-rich wort before heating to the gelatinisation temperature (70 C) so that you don't denature those enzymes in the process. When the wort is chilled back down to 70 C, post boiling, then the enzymes may be safely added for saccharification.

As mentioned before, there aren't many gluten-free malts readily available for brewers so you may consider making your own malt. I have never attempted it, but it sounds like a tedious process - soaking grains in buckets for several days, aerating and flushing every 8 hours, then drying in a dehydrator in small batches before kilning. I can recommend a gluten free home brewing store in Oregon that has plenty of gluten-free malt that you can purchase or further instructions on making your own malt. You can also see about sourcing malt from Grouse Malting & Roasting Co. or Eckert Malting & Brewing Co.

Tips on Style

Andrew Lavery recommends brewing witbier, weizen, dunkelweisen and roggenbier for decent gluten-free recipes since they are typically yeast-driven styles that allow for some sourness/tartness, using gluten-free grains that are wheat-like (millet). Additionally, English, German and Belgian ale yeasts tend to be more forgiving, along with lots of noble hops. Pale beers, particularly lagers, are to be avoided when using sorghum malt since it imparts a slight sourness that has nowhere to hide in those styles. I've had success with a pale ale using only sorghum LME, but admittedly it took 3-4 weeks conditioning in a keg before the flavor mellowed out.

Additional Resources

Gluten-Free Homebrewing.org - this is an online store that sells GF brewing ingredients exclusively and also has some informative tutorials

Home-brew Academy - this is an article entitled "What Every Brewer Should Know Before Attempting a Gluten Free Recipe.

Celiac.org - general information regarding gluten-free foods

Very Well Health - here’s a robust resource regarding Celiac Disease

So there's your introduction to gluten free brewing. It can be as simple as substituting liquid sorghum malt extract into an all-extract recipe, or as complicated as malting your own grains and carrying out a multi-rest mash. The challenge is in finding the right combination of ingredients to still make it taste like "beer". Good luck!