Experimentation is much of the appeal of brewing, and methods of integrating alternative ingredients such as spices or assorted sugars into a recipe are fairly clear cut. Unmalted grains, on the other hand, are a bit more complicated, and are essentially useless handled incorrectly.
Mashing is the fundamental brewing process whereby grain starches are converted to fermentable sugars by enzymes (amylase) contained in malt. It is nothing more than crushed grain mixed with water and held at 150 degrees F (give or take) for one hour. Since unmalted grain (either raw or flaked) contains none of the magical enzymes, they must be used in conjunction with malted grain, typically barley.
Some consider it heresy to use many unmalted grains, given the negative connotation attached to the word “adjunct,” specifically the notion that the sole function of adjunct grains is to make lighter, cheaper beer. On the contrary, these additions can enrich beer in many ways through flavor and effect, and brewers must consider both the type (wheat, corn, rice, etc) and form (raw, flaked or torrified) when using them.
This column is geared towards partial or full-mash brewers, since steeping these alternative grains for extract brewing, as one would specialty grains, will contribute only unwelcomed, insoluble starch. The objective is to render them fermentable, and take advantage of auxiliary characteristics, like head and body augmentation.
Perhaps this information will serve to demystify non-malted grains, however unusual, and provide a little impetus to those who want to delve into some experimentation with classic or indigenous beer styles.
Raw Cereal Grain
An extensive array of raw grain like corn, rice, wheat, oats, barley, quinoa, millet, sorghum, buckwheat and rye can be found in virtually any store that sells bulk groceries. All can all be used to make your beer more interesting. Rye and buckwheat in particular have a fairly strong flavor and will stand up to darker brews. Others are useful to lighten body while adding fermentables, contributing a minor flavor profile, and/or adding some mouthfeel, silkiness and texture at the same time.
The key to using them, though, starts with a process called gelatinization, essentially cooking the raw grain with water to swell and unfold the starch, transforming it into a fermentable product.
The method entails cooking the grain separately and then adding it to the main, malted grain mash. Essentially, you will be making a batch of thin hot cereal. Mill the grain as you would your barley malt and mix with enough water to make a loose porridge, then cook until soft, usually 20 minutes or more. Bear in mind that the cereal will absorb a lot of water so be mindful of scorching.
When the cooking step is finished, cut off the heat and mix in enough cool water to bring it to roughly your mash temperature. It will take a bit of shrewd coordination, as there will be malted grain in the mash tun and cereal in a separate kettle, but as with most homebrewing experiments, a little planning and confidence goes a long way (breweries that use adjunct grain or cereal have a separate cooker for this very purpose).
The malted grains in the mash have more than enough enzymatic power to convert the raw, gelatinized grain to fermentable wort. Keep the raw grain portion to 30 percent or less of the total grain bill by weight. Stir the mash now and then to keep the enzymes in contact with the starch. It never hurts to add a pound of inert rice hulls to the mash to aid in lautering, since raw grain contains no husk.
It is useful to know that some grains have a low gelatinization temperature and can be used without cooking. Wheat is one, and this is why raw wheat is used in witbier to full effect and without any adverse consequences. Most need cooking, though, so to be safe when using any of the others, do the gelatinization step.
Classic American pilsner uses about 25 to 30 percent corn grits, and was the first lager made by Central European immigrants. Buckwheat is outstanding in porter, stout and brown ale. Brown rice is a nice, nutty addition to lighter ales. Even multi-grain recipes can be formulated, provided you have enough base malt to complete the conversion of the starches. Rule of thumb would be to start with about 20 percent adjunct and go from there. Oats and rye are very popular grains for their mouthfeel and flavor contribution, and are usually used in flaked form.
No doubt you have seen assorted flaked grains at the homebrew shop or on a mail order website. Corn (or “maize,” if you prefer), oats, rice, wheat, barley and rye are the most common. Flaked grains are simply raw grains that have been gelatinized, flattened and dried. They are ready to use in a mash and, like raw versions, must be mashed with malted grain as they lack the requisite amylase for conversion. I cringe when I see flaked grain listed with specialty malt as the steeping portion of extract recipes. Once again, the flakes are contributing nothing but messy, useless starch.
The good news about flakes is that they can be added directly to the mash without any further middling, and will literally disappear. Use the same parameters as raw grain regarding grist percentage, mash manipulation and lautering considerations. Flaked, or rolled oats, can be purchased at any grocery store and even at 10 percent will add a noticeable creamy viscosity to the head and mouthfeel of a brew.
Rye has become perhaps the most popular flaked grain in the past few years and shows up in everything from pale ale to bock. Not only does it add the silkiness that oats does, but it also has a fairly distinct flavor. A classic Irish dry stout recipe would include 10 percent roasted barley, 65 percent English pale ale malt and 25 percent flaked barley. Flaked maize is used in many an English or Belgian ale on the commercial level, so if you can put Reinheitsgebot bias aside for a recipe or two, incorporate up to 20 percent into your next batch. Torrified wheat is found at nearly every homebrew ingredient purveyor. It is raw wheat that has been heat treated to the same effect as flaking, similar to puffed cereal.
Brewers are well aware that wheat, rye and oats also come in malted form. They are worth mentioning here, as there is bit to know about using them. Being a base malt, they have the enzymatic muscle to pull their own weight in a mash, so it is possible to back off on barley malt if you want make a beer of rye or wheat malt plus raw or flaked grain. Generally, wheat and rye malt are used in conjunction with barley malt to create classic weizen or roggenbier, respectively. Even in malted form they contain no husk, so be wary of the dreaded stuck mash by using rice hulls, especially with rye. Their use goes well beyond the traditional though, as many brewers have made obvious in recent years. The robust, spicy flavor and full body of rye works well in barley wine, imperial stout, and even a bottom-fermented, Munich and rye malt-accented “roggenbock.” It would be wise to employ a step infusion mash that includes a protein rest for 20 to 30 minutes at 122 degrees F to break down the troublesome protein matrix. Certainly they are capable of being used in a side or mini mash for hybrid brewers without any issue.