Extracts and Syrups
The options for gluten free extract brewing are a little more limited than in the conventional (barley-based) homebrew world. Currently there are no gluten free liquid or dry malt extract (LME or DME) equivalents. Three reasonably easy to source, and relatively inexpensive options include sorghum syrup, rice syrup, and rice syrup solids.
In North America at least, sorghum syrup for brewing is made from unmalted sorghum grain (versus cane).
Some people describe a metallic or slightly sour/acidic twang associated with beers made solely or primarily from sorghum. Potential remedies for overcoming or masking the flavor include:
- Using a combination of sorghum and rice syrup (e.g. 4:1 or 5:1 sorghum:rice)
- Providing additional yeast nutrients in the form of DAP
- Using calcium chloride
- Using citrus-profile hops that might mask or compliment the sorghum flavor
Rice Syrup and Rice Syrup Solids
"Adjuncts" and "Partial Mash"
Without going to all grain brewing, you can extend or supplement your extract brewing with raw and malted grains (and other starch / protein sources) to achieve a few different objectives. These can include increased body, better foam formation and retention, or to impart roasted and other specialty malt attributes. The typical approach to doing this would be to steep theses additions in your kettle before your wort reaches boiling temperature. Use a nylon bag or other porous, heat safe container to steep at approximately 145F - 170F (63C - 77C) for 30-45 minutes. Depending on the pH level of the wort in the kettle, raising the temperature above that range (or boiling) may extract some harsh flavours from the tannins of those ingredients.
Enzymes are not generally used or needed in extract brewing (where the sugars from sorghum or rice syrup have already been made available and concentrated). Without enzyme additions, raw (unmalted) grain and to a large extent malted grain additions will not contribute to fermentable sugars in your extract beer. Any starches extracted from steeping will likely remain as unfermentable material in your final beer. This should contribute to the perception of "body" without necessarily increasing sweetness. A caveat is that residual starch may contribute to a hazy beer and some increased risk of spoilage and reduced shelf-life.
Note that grains and pseudo-cereals that have been pre-gelatinized will more readily contribute starches through steeping. Examples include "flaked", "rolled", "puffed" and "torrefied" products.
Raw / unmalted adjuncts for extract brewing
- High in protein and low in fat, flaked quinoa can be a positive contributor to foam retention and body.
- Although high in protein, oats are also higher in fats. Without enzymatic activity to break down lipids, this option may contribute body ("creaminess") but at the expense of foam formation and retention.
- Lentils are high in protein and low in fat. When prepared properly, they are excellent contributors to foam and neutral in flavor.
- Ground Breaker Brewing recommends toasting red split lentils in a shallow pan at 375F / 190C for 20 - 25 minutes, stirring frequently, to remove any raw character. They should smell nutty. 
- Unmalted buckwheat can be found in many grocery stores, in either whole or husked format (sometimes sold as "kasha").
- Malted gluten free buckwheat is also available through maltsters and distributors.
- Buckwheat is higher in beta glucan (which can contribute to body), as well as protein. It is an excellent foam contributor, though can also lend an earthiness that may not be appropriate i*n some subtle beer styles.
- Raw millet, raw sorghum
- Unmalted versions of these grains are reasonably available in grocery stores in whole grain format.
- Although protein content is more modest in comparison to the other items listed above, steeping these raw grains may contribute somewhat to foam as well as to body.
- Gluten free maltodextrin (derived from tapicoca for example) can provide some unfermentable dextrins (long chain sugars) that will contribute to body.
- See also
Malted grain adjuncts for extract brewing
- Crystal and caramel malts
- The conversion of starch to sugar for these malts is mostly accomplished during the malting process. This means that extract brewers can leverage the full potential of these malts without adding enzymes. Crystal and caramel malts will provide both fermentable and unfermentable sugar potential, as well as color and flavor contributions (ranging from honey and brown sugar to dark fruits and toffee).
- Dark roast malts (e.g. dark roast rice and millet, gas hog rice malt)
- Small amounts of these malts can provide color and roast flavors. The roasting process generally means they have lower extract potential to begin with and are less likely to contribute residual starch to the finished beer.
- Other specialty malts (Munich, Vienna, amber, etc)
- These malts may provide some desirable flavor attributes. Because of their higher starch content (relative to crystal and dark roast malts) brewers should exercise caution in using as an adjunct in extract beers without use of enzymes.
- See List of Commercial Gluten Free Malts