Brewing with Adjuncts: A Cereal Mash HowTo

There are several reasons why you might want to do a cereal mash:

1. You're brewing a style that calls for rice or corn adjuncts, such as a Classic American Pilsner.
2. You're brewing an Oatmeal Stout or some other beer that calls for un-malted grains.
3. You're using some un-malted barley or wheat.

In any of these scenarios, a portion of your mash will consists of grain that hasn't been malted. These grains lack the enzymes created during malting, and the starches they contain are not readily convertible to the sugars you need for brewing. Fortunately, the malted grains in your mash will have enough enzymes to convert all their own starch and more, but you'll need to go through an additional cooking process to gelatinize the un-malted starches to make them ready for the mash. If you think you might come up short on diastic power, you can replace some of the 2-row malt in your recipe with 6-row.

As with other brewing ingredients, there are shortcuts. If you're brewing a style that calls for rice or corn adjuncts, you can skip the extra process by buying pre-gelatinized “flaked” rice or corn at the homebrew store. No need to run any of this stuff through a grain mill, just toss it into your mash. As with malt extracts, buying special ingredients will be more expensive than using the 'regular' grains. You can also use instant rice, oatmeal or grits to reduce your cooking time.

Various sources use the term 'Cereal Mash', but it's really a 'Cereal Boil'. More on this later. The boil is used to break down the starches in un-malted grains to make them accessible to the enzymes in the main mash. If you're using grits or oatmeal, you won't need to mill these grains before starting the boil. If you're using rice, un-malted barley or wheat you'll want to mill them first. It will take significantly more effort to mill these grains than to mill their malted counterparts.

If you want to streamline the process you will need a pot large enough to hold your adjunct(s) and the boil water. Let's take a look a the process. Determine the amount of water you'll need, usually, about 3 to 4 quarts per pound of grain. Heat the water to boiling, add your grains and continue to boil for at least 30 minutes. Stir constantly so the mash doesn't scorch. Bits of grain will start to stick to your stirring spoon as the grain breaks down and the starches start to gelatinze.

Once the cereal boil is complete you can just add it directly to your mash. You can (and should) be strategic about this and use it as a way to do a stepped mash. You could (for example) mash in at 140, and use the cereal boil to raise your mash temps to 152. As long as your cereal mash is only a small part of the overall grain bill, you shouldn't notice any difference in the mash or sparge processes. If you're using a lot of adjuncts, you may want to add rice hulls to prevent a stuck mash.

I've never been able to figure out the reasoning behind what seems to be the 'official' way to do a cereal mash. The problem is that the 'mash' attempts to convert the starch that isn't convertible yet because it hasn't gone through the boil yet; using a quantity of malt that falls well short of  having enough enzymes to be useful. To make it work you'll need to manage two mashes at the same time, or you'll need to add a bunch of time to your brew day so you can com[plete your cereal mash before starting your real mash. But in case you're interested here's what to do:

1. Add 1/4 cup of malt along with 2-3 quarts heated water per pound of grain to reach a mash temperature of about 158°F for corn or rice, 145°F for barley wheat or rye. Hold the temperature there for 15 minutes.
2. Bring the cereal mash up to a boil and hold it for 30 minutes.
3. Add the cereal mash to the main mash.

Campden Tablets

Campden Tablets have four main purposes for beer, cider, mead and wine makers:
1. Removing chlorine / chloramine
2. Sanitizing fermentables
3. Sanitizing equipment
4. Stabilization

Anhydrous sodium metabisulfite (Na2S205) is typically the active ingredient in Campden tablets. Each Campden Tablet equals 1/16 teaspoon of sodium metabisulfite. When combined with water, the tablets provide an easy-to-measure delivery mechanism for adding approximately 75 parts-per-million (PPM) of sulfur dioxide (SO2) to each gallon of liquid and to the headspace in vessels used in fermenting.

In simple terms, dissolved Campden tablets kill microorganisms, but only for a while until the sulfur dioxide from the tablets dissipates to non-lethal levels for the little critters. At the proper levels they can be used to kill wild yeast, mold, bacteria and other microorganisms that might otherwise spoil what you're brewing; and after they're done you can add your own yeast to start fermentation. As an alternative you can also purchase potassium metabisulfite in bulk but then you need to measure tiny amounts of it instead of counting out a few tablets.

Small amounts of Campden tablets have the handy side-effect of precipitating chlorine and chloramine out of water. This is only a factor if you're using chlorinated water, such as a city water supply, and you're not using some other method of removing the chlorine such as reverse osmosis (RO), charcoal filtration or boiling. You want to remove the chlorine and chloramine because when left in the water, they can form smelly compounds called chlorophenols when they interact with beer.

I prefer Campden tablets to the other methods for dechlorination. Reverse osmosis is significantly more expensive. Filtering typically removes only a portion of the chlorine and chloramine, and it's also more expensive than Campden tablets. Both RO and filtering require additional equipment that you need to store and maintain. Boiling doesn't work on chloramine and it adds time to your brew day.

To use Campden tablets for Removing chlorine and/or chloramine, crush one tablet and add it to 20 gallons of water, or use 1/4 tablet for each five gallons. Don't over-think this: if you're somewhere near 1/4 tablet and somewhere near five gallons you'll be just fine. I toss a crushed partial tablet into the hot liquor tank before I start heating the water. Stir it up a bit and I'm ready to go.

To use Campden tablets sanitizing fermentables, add one or two tablets to each gallon of cider or must. Tablets should be crushed and dissolved in a small amount of water, then added to the must immediately. Wait 12 to 24 hours before adding your yeast to begin fermentation. For use with overripe and potentially spoiled fruit, go with two tablets and two days. For regular use, one tablet and one day. Allow the fermentable liquid to ventilate in an open container.

As far as I'm concerned, using Campden tablets sanitizing equipment makes no sense to me because StarSan and Iodophor are quicker, cheaper and easier to use. but if you have an bunch of tablets you want to use up, here's how to do it according to E.C. Kraus...

All equipment should be cleaned with soapy water first. Crush and dissolve sixteen (16) Campden Tablets per each gallon of water. Also add 1/2 teaspoon of Citric Acid. Sanitize fermentation vessels by putting in 2 to 3 inches of solution in the bottom of the vessel. Seal the vessel air-tight for 20 minutes to allow the fumes from the solution to permeate the inside walls. You can also put in the vessel other equipment such as hoses, hydrometer, air-locks, rubber stoppers to be sanitized at the same time.

One Campden tablet can be added to each gallon of wine prior to bottling to preserve color and flavor. Crush the tablets and dissolve them in a small amount of the wine first. Potassium sorbate can also be added just before bottling time to eliminate re-fermentation.

Beware that beer, wine and other beverages treated with Campden tablets or sodium metabisulfite will retain trace amounts of sulfites after most of the SO2 has dissipated. Sulfites occur naturally in your body are generally not a problem except for a few people who are deficient in the natural enzyme to break them down. Allergic reactions have also been reported. Most commercial wines made in this country warn of sulfites on the label, except for the few that don't contain sulfites. Wines produced in other countries may not have the warning even though they contain the sulfites.