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What to do when you have a stuck mash

Jeremy Short · Dec. 11


You just spent $50 on ingredients and you've been mashing your grains for an hour then you go to separate out your wort and ... what the ... holy hell the wort isn't coming out. What do I do? Help! Oh, man, this was going to be the best pale ale ever! Don't worry, yet. I've been stranded with a stuck mash a few times. It's the worst damn thing to happen on a brew day. So far I've been able to save each of these stuck mashes using one or a combo the techniques below

Remember! This a hot hot mash. Be careful!

The Big Dig

This is pretty straight forward. Just take your mash paddle to the bottom of the mash tun and twist it around the top of the false bottom. Sometimes you can open up a channel for the wort to flow through.

The Poker

This has worked for me several times. Open up your valve and poke a thin stick through the valve going back and forth to loosen up any clogging bits of grain. I use my thermometer for this and it works brilliantly. Remember that's some hot liquid that can come rushing out of there.

The Full Dump

I've only resorted to this one once. In my early hombrewing adventures I once looked disaster in the face. It was frightening. A 22 lbs. grain bill was about to go down but I wasn't about to give up. Not when beer is on the line. For this fix I literally dumped the full grist into my bottling bucket. Remember this is dangerous, heavy, and hot! I let the mash cool down to a manageable temp and scooped the grist out of the mash tun with a large spoon. Once it was low enough to pick up I dumped the rest. After clearing the clog I slowly added the mash back to the tun with sparge water and started collecting wort. This is not fun. This is not a great solution. But it did work and the beer actually turned out great.   

The Pump & Save

I used this technique recently. I had become a bit cocky since I had avoided a stuck mash for many many batches. Plus my Blichmann is a very forgiving mash tun and much harder to get stuck than my old homemade cooler mash tun. I filled the tun to it's max capacity (a mistake) and opened up the valve to discover it was bone dry. Nothing was coming out. I cried. But I also own a pump. I primed the pump with some water and hooked it up to the mash tun. It chugged, it pulled, it growled, it moaned, but slowly the wort began to flow until it ran clean and smooth. If you have a pump, this is a pretty slick and easy way to fix a stuck mash. Many pumps cannot run dry. Check out your owners manual.

The you're screwed method or how to make sure this doesn't happen again

There's nothing good about a stuck mash and it's possible you are simply out of luck and you will be unable to save your grain and wort. Personally I would try all these things before giving up. Either way, it's a good idea to think about avoiding this problem with the following techniques:

  • Pull your wort slowly and allow the grain to settle. If you open your valve all the way up you can end up pulling the wort so quickly that the grain will lock up and not let the wort flow through the mash.
  • Rice hulls - these are a great addition to any mash. They help keep a more even temperature throughout the mash and help prevent stuck mashes.
  • A thinner mash. Add more water to your mash tun.
  • Be sure to check your false bottom before putting in your grain. Is it sealed? Will any grain creep in?

And, remember, that mash is hot! Don’t do anything stupid.


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