HomeBrewers CornerCereal Mash

With the upcoming Iron Brewer, there is a good chance that some brewers will have to deal with adjuncts for the first time. Adjuncts are typically unmalted grains that are used in brewing to supplement the main ingredient – malted barley. They are used for a variety of reasons: cutting cost, balancing flavors or creating some special flavor or characteristic in that beer. Normally these come in the form of corn, rice, rye, wheat, unmalted barley or other even grains like sorgum or flax.

Normally, we buy these ingredients already malted or flaxed. That means they have been prepared to render the starches accessible and easily converted (in the presence of sufficient enzymes) to sugars in the mash.

When dealing with unmalted adjuncts, the brewer needs to render the starches accessible to the other grains which can then convert the starches to sugar. This usually means boiling them to break them down along with other components, like glucans.

John Palmer’s “How to Brew” has a great description of this process that is more detailed than what I have room for here. But here is the process in short:

  1. Crush the adjunct if possible.  This can’t be done with harder grains like dried corn unless you have a hammer mill or a really hard head.
  2. Mill some barley and put it in with the adjunct. This isn’t required. In fact, you could just go straight to step five but I get much better yield following these steps.  I usually do about a 1:1 ratio here.
  3. Use as much water as twice what you normally use for a mash (like a 3:1 ratio)
  4. Do a mini-step mash – heat the mixture up to 122, hold for 15, take it to 145, hold for 15, take it to 155, hold for 15, take it for 165, hold for 15.
  5. Boil the crap out of it until it looks like a uniform goo instead of grains in water. If you did the steps right, this won’t take as long as if you didn’t.  But for some grains, like oats, this isn’t all that long.

Then you put it into your mash. It’s almost like a decoction at this point as adding the hot grains will raise the mash temp. And you may need to mash longer than normal – an iodine test is good to try here or just give yourself 90 minutes to mash.

Yes, this is labor intensive, which is why I buy flaked, rolled or malted grains since a cereal mash isn’t needed. But you may need to know how to do this for Iron Brewer since you will need to buy the grains at the local HEB as we will probably be using something that isn’t at AHS.

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