What techniques do you use to condition malt? (AKA wet crush)

Malt Conditioning is adding a small amount of moisture to grain before the crush. The HomebrewTalk Wiki recommends raising the moisture content by 2%, or 100ml of water per 5kg of grain. What techniques and equipment do you employ to condition grain before the crush?

The squirt bottle technique sounds a little laborious and error prone. I'd like something more sure.

The February 4, 2010 episode of Basic Brewing Radio is about Malt Conditioning. Gonna go have a listen.

  • What happened with the bounty on this question Dean?
    – brewchez
    Feb 4 '10 at 15:41
  • Should have gone to the highest-voted answer: yours Feb 4 '10 at 16:18
  • Should have gone to the highest-voted answer: yours.Check your reputation for today: brewadvice.com/users/recent/99 Feb 4 '10 at 16:19
  • Thats what I thought would happen, I just don't see a 100pt uptick in the stats. Its tough to tell from the graph and I don't see it in the chart to the right of it. Just curious more from a site functionality standpoint.
    – brewchez
    Feb 5 '10 at 18:34
  • Just read the FAQ brewadvice.com/faq Says that if I don't accept an answer before the bounty expires the top-voted answer gets half the bounty. I owe you 50 rep points. Feb 5 '10 at 19:03

If I were going to attempt to do this I'd use a squirt bottle. I'd weigh the grain. Then I'd measure out water to 3% of the grain weight. 3% to account for over spray and evaporation.

I'd warm the water some, or at least make sure it was at room temp ~70-75F. Put the grist bill in a large bottomed party tub. Spray the top layer slightly. Then mix the top layer into the base layers. Spray again and mix. Spray sparingly to prevent soaking the malt. Keep going until all the water has been spent.

Then I'd transfer the malt to a plastic bag and tie it off to keep the moisture in the malt.

I'd preheat a cooler with a gallon of near boiling water, to get the cooler warm. I'd dump out the water and put the bag in the cooler and close the lid. This will help keep the malt warm to help get that moisture you added more vaporized and able to penetrate the malt.

After 20 minutes, much of the malt should be more hydrated. I'd crush as normal.

This is how I'd start. Experimenting with the "incubation" time might be needed after the fact on subsequent brews.

  • Wow. This is involved. How wet do you find the grain is with this process? Dec 3 '12 at 20:19
  • You indicate that you have never done it. That's why I down voted. Just misting it with a spray bottle is enough as you transfer it to another bucket. That's how I do it now. It's easy and it works well.
    – Pale Ale
    May 17 '17 at 17:26

Ok, this is an ancient question but I'm going to add my process since it is considerably different.

First, I don't think I'm 'properly' conditioning the grain in terms of substantially hydrating it. Instead my goal is just to add a touch of moisture to reduce the dust and hopefully keep the hulls a little more intact.

I take a very small amount of warm water in the range of 8 to maximum 16 oz. That's for 25 to 30 lbs of grain (10 gallon all-grain). I'd stick to a cup for 5g batches. Then I dip my clean hands in the water and run my hands through the grain. I do this repeatedly until the water is gone. You will notice a change as you do it in terms of the amount of material sticking to your hands. I use this as a vague gauge of moisture content. A spray bottle would likely work just as well. I just like using my hands because I get feedback on the increasing moisture levels, something a spray bottle doesn't let you do.

Is this proper conditioning? I'm sure it is not but I get higher percentage of intact hulls, the kernels still fracture nicely, the grain is not so wet that it causes problems with my Barley Crusher, and the dust levels produced by milling are much reduced.

Some other milling tips: - Don't grind flakes and certainly don't wet and grind flakes. You will only do this once if you make this mistake :) - Don't grind inside: even with my wetting procedure, dust ends up everywhere. - Don't endlessly expose yourself to airborne barley dust. Homebrew levels of exposure are probably not a problem but extensive exposure can cause occupational asthma. - Don't grind near electric motors. There is a very very very small but real risk of explosion. Very unlikely grinding a 5 gallon batch but if you ground batch after batch in a small basement room and then ran equipment like a dryer...

  • I did the flakes once too - That is a great comment. I will never do the flakes again---ever.
    – Pale Ale
    May 17 '17 at 17:22

I've tried both conditioning the grain and milling it dry. Conditioning kept the dust down, but other than that I found no differences between the 2 methods.


Steeping your grain for 15-30 minutes at 30-50 degrees Celsius will raise the overall moisture by 30%. The corns are squeezed out of their husks when they are milled wet. The idea is that the husks remain in tact, and create a more porous bed for single infusion mash tun systems. The problem with this technique is that under-modified “hard ends” are not ground up and this can result in as much as 3% in loss of extract. Wet mills haven’t been made since the 1970’s and I think they are only in production at the Steinecker brewhouses nowadays. I really don’t know where else you would find more information about this except from the text book Malts and Malting by Dennis E. Briggs as it has become more of an academically known process and not one used within the industry.

  • 1
    A 30% moisture increase is pretty high (see question). I do not want to use a special wet mill, just my regular crusher. Jan 18 '10 at 19:31

I found the following through another website and have not attempted myself. I have never even heard fo this before now and am interested to try. here is someone else's process that sounds easy enough to me.

To condition the malt put the malt in a bucket and use a spray bottle filled with water to spray the top of the malt a few times. Now mix the malt and repeat. You want to distribute the added moisture as evenly though the malt as possible. Soon the malt's feel with become less like dry straw and more like leather. Once it looses it's dry feel and a few of the kernels start to stick to your hands let the malt sit for a few minutes to let the husks soak up the moisture. Get the mill ready and set it fairly tight. After all, you conditioned the malt to be able to crush it tighter. I set mine to 0.55 mm (22 mil). When you mill the malt you will notice that once in a while a crushed kernel will stick to a roller of the mill. This is ok and it only becomes a problem if a dough starts to build up on the rollers. In this case you used to much water. Run some dry malt through the mill to remove the dough.

After crushing a hand full, look at the crush. You want to see kernels that look more flattened (like oatmeal) than crushed. Pick them up and the endosperm should be dry and come out easily. If this is the case you can continue crushing the rest. If they still look more broken than flattened add more moisture and try again. In the beginning you may want to stay on the safe side and don't add to much water to avoid the risk of doughing-up the rollers.

I think I will try next batch! Great question.

  • That technique came from the wiki page I linked to in the question. Looking for different ideas. Jan 29 '10 at 5:06
  • Don't forget to vote the question up if you think it is great. Also, that technique came from the definition I linked to. Already read that one. Jan 29 '10 at 5:10

I'd skip the idea of wet milling all together.

My experience shows that adding 5% water and just temper the grains.

The extra water will toughen the husk and mellow the endosperm much like what is done in flour milling.

Roll diameter is more important than water.

Even better yet would be to have two sets of rolls and a sifter box.

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