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Malt conditioning

A couple weeks back I complained about the performance of my grain mill. It has been pretty inconsistent for me. Before giving up on it, I wanted to give malt conditioning a try. Malt conditioning is the process of adding a small amount moisture to your malt before crushing it. The moisture softens the husks on the malted barley, which allows for more of the husk to pass through a mill intact, while the endosperm still is cracked and exposed. More intact husks allows for better draining of the mash, which is especially important for me because I use an recirculating mash system (C-HERMS, specifically). A poorly milled mash can cause serious headache with such designs.

So, today I finally gave it a shot. I calculated that I would need roughly 150-200ml of water absorbed into my malt. First I measured out 19 lbs of the various grains that I would use to brew my American pale ale into a 5 gallon bucket. Then, using a second 5 gallon bucket, I would transfer over a couple pounds of grain, mist with a spray bottle that had been filled with the required volume of water, and mix it around with a wooden spoon. I did this for the whole grain bill and it took a couple minutes total. It was quite a relaxing process actually.


19lbs of malt, 0.39lbs of water to achieve 2% moisture content.
Conditioned. 19lbs of malt, and 0.39lbs of water to achieve 2% moisture content.


Since the husk is more pliable, it’s possible to mill at a smaller roller gap. I started with a 0.022″ roller gap, but the mill was unable to pull anything through at this distance (one of the drawbacks of small roller diameters – mine are 1.25″ diameter). I increased by three thousandths of an inch until the grain would actually pull through. 0.028″ was the ticket (compare this to a standard setting of 0.035″+ for these sorts of mills).


0.028″ is when my mill would start to effectively pull grain through. It also happened to result in a nice crush of conditioned malt.


The resulting crush had largely intact husks, but completely separated endosperm. It also felt quite fluffy. As an added benefit very little airborne dust was produced when milling the conditioned malt. I felt there was a bit more consistency in the crush when milling at a smaller gap too.


Conditioned, crushed, and [relatively] consistent.

The mash was well suspended. Recirculation worked fast and without issue.


Well suspended, good recirculation performance. I’m happy.


Here's a shot after the mash has been drained. It really shows just how intact the grain husks remain, and also how well crushed and separated the endosperm is.
After the mash has been drained, you can really see how intact the grain husks have remained, as well as how well crushed and separated the endosperm are.


And I hit my numbers right on! (85% mash efficiency with single batch sparge, 82% total efficiency). I’d count this one as a win, and it will now be a regular part of my process. It has lowered my ambitions to get a better mill for the time being, as well as a false bottom. If you don’t condition your malt already, give it a shot!


I like to think good numbers = good beer.




Published in Brewing Equipment


  1. What mill do you currently use? I have the OBKrusher and I’m not very happy with it.

    It seems like malt conditioning adds quite a bit of extra work during the milling phase. How did you deal with scooping the wet grain out of the bucket into your tun? I’m just curious, because I’ve never tried it myself.

    • Justin

      Ya it’s an OBKrusher… I used tools to tighten the thumbscrew when setting the roller gap in an attempt to reduce drift which has been a large issue for me.

      Most of the crushed malt comes out of the bucket, but there were bits that got stuck in there for sure. What I did is drain some of the mash tun liquid into the bucket, give it a swirl and tossed it back in (did this twice).

      As for extra time… it was a couple extra minutes while waiting for water to heat up and stuff. The actual conditioning I don’t find takes long. The OBKrusher is a bit slow to mill though. I really try not to worry so much about how long I take brewing nowadays… I used to… and would do things like brew 3 batches in a day and totally exhaust myself. Everything is done at a meditative pace now… except for maybe the last 5 minutes of the boil where I’m preparing the transfer to the fermentor/preparing the wort chiller/preparing for aeration/making late hop additions… that’s a bit hectic :)

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