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More "Stuck" mash

I had another stuck mash today, I am starting to get a little discouraged. I milled the grain to a confirmed 0.038", so I know it can’t be the crush. I am thinking my false bottom may be effed up.

I did 15.5 # of grain for a 5 gallon brew (german pils and cara 8 grains only), 6 gallons of strike water. I also added about 6 ounces of rice hulls, pre-soaked in hot water to make sure they didn’t mess up my water calculations. When I went to vorlauf, absolutely NOTHING came out. I vorlauf with a pump, but in the past I did not throttle the pump down (I now do, but maybe it did some damage… even though it never resulted in any trouble in the past). this is also a pretty heavy grain bill + water, so not sure if the mash tun weight was too much for it to handle right now.

I took an air compressor, blew air through the MT output valve back into the mash. I was able to get air bubbles to rise up through the wort without much issue. Then, I quickly removed the compressor, and next to no liquid came out of the MT valve. It was almost like any gunk that I freed up with the air came right back to clog up the valve. I then donned some long rubber gloves to try to dig around at the bottom of the MT, possibly clearing any debris and such from the top of the false bottom, but to no avail. During a moment of desperation, I even tried sucking out of the hose as if it were a big straw, and I got light headed before I got any wort in my mouth.

So, I poured the entire mash into another vessel, took apart the entire MT, false bottom and all. I can say that the false bottom doesn’t look destroyed, but it definitely isn’t sitting flat on my granite counter top. One side of the false bottom is lifted off the counter by about 1/8", maybe a little more. It doesn’t feel like it is lifted enough to give me this sort of issue. Since I blew air through the lines, I can’t imagine there was any sort of vacuum/bubble issue, I am almost certain the line was somewhat clogged (or somehow the tubing between my false bottom and the MT output was crushed?). I then cleaned out the false bottom and the entire MT, re-assembled, poured all the grain and wort back into the vessel… and still no movement. After trying to figure it out for 2.5-3 hours, I gave up and called it a day.

Anyone have any ideas? I just purchased a SS mesh tube (like the bazooka screen tube), but in theory that could just get flattened under the mash weight. I am at a loss, this is the second time in 3 weeks that I tried to make this particular beer, and got a “stuck” mash both times… which are my first and only stuck mashes ever. The only thing that has changed between these 2 brews and all of my past brews is that I am milling my grains now, but even scooping the grist out of the mash tun, it looks plenty coarse to not be creating any sort of paste.

That’s not really a super thick mash. It sounds like your false bottom is failing you and grain is clogging your pickup tube.

People use stainless tubes and stainless water lines all the time with heavier grist bills and they work fine or you could use a bag. Whatever is cheapest to test out the theory that your false bottom is failing.

Can’t be your pump if it doesn’t even drip out under gravity with the valve open…

Are you sure your ball valve is opening? Just a wild guess…

Yea I was thinking of trying a bazooka tube and a biab bag instead of the false bottom next time… Maybe even do the bag only, no bazooka tube and no false bottom. Either way it’s super weird and pretty frustrating, I just don’t wanna waste any more time


yea i don’t blame you. I’d be losing it. I love my brew bag. If you have a three vessel system you could use it the same way as a false bottom. My system is 2 vessels so I have a hoist to pull the bag when I brew 10 gal batches or big beers.

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Yea I do have a 3 vessel system. If the bag works, I probably will just use it every time and do a weird BiaB/ regular all grain hybrid. Then, who knows, I may ditch the false bottom altogether.

That’s what I do. I mash biab in the kettle at more traditional water to grain ratios, pull the bag and sparge by pumping water through the grain bag and letting it drain into the kettle as I begin the boil.

Yea that sounds like it would work. I will put the bag inside the mash tun (big igloo cooler with false bottom), and then let the bag do the extra straining for me but use the system exactly the same as I do now. Basically, replacing my false bottom with a BiaB bag


I’ve never had a stuck mash with a bag

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Ive done just that brew bag in my kettle/tun and drained to the brew pot didn’t pull the bag and still eliminated the vorlouf. No loss to efficiency

If the bag works for me to replace the false bottom, I will probably use it for a while. Long term, I would like to get back to a false bottom again, but not at the expense of my brews.

Did you do any stirring of the grain during the mash? If the grain got compacted then you would not have good flow.

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Stirred the mash every 12 minutes, so 5 times over the course of the sach hour… Couldn’t have been that

My thought… A warped false bottom won’t make or break the mash process… I’ll suggest a full volume mash… All the hot liquor in the mash-tun… In fact, the mash-tun could be yer boil kettle now… Grains in a bag or basket…

I have been using a non-adjustable JSP malt mill for 20 years or more. Never had a stuck mash with several different MTs home made and my current from Morebeer. From what I can gather they are set at .045. Kind of wide for most. My LHBS has the same mill. They say that homebrew shops use a wider setting so you don’t get a stuck mash. It may hurt efficiency but for the small size we brew it’s easy to just add more grain. Commercial breweries need to squeeze as much out of the grain as possible to lower cost.

I’m not saying that is your problem @GoBlue59 Just something to think about.

I hear ya. The fact that I can’t get ANY liquid out is what keeps bugging the crap out of me. There is no way this is too fine of a crush to get zero wort out, I can guarantee it. the whole mash tun is acting like the output valve is clogged, because like I said… I couldn’t even siphon liquid out with my mouth from the output valve. The only way I could get liquid out of the valve was to stick a pipe cleaning brush through the ball valve and into the bottom of the vessel, but then the flow would stop immediately after I removed the cleaner, so clearly the output of my mash tun is getting blocked by solids (at least that is what makes sense to me).

At the very least, a properly working false bottom/ mesh tube/ BiaB bag would prevent any grain from getting near the output valve, so I could eliminate this issue

Perhaps… you’ve got sticky water? :joy:
Without being there to see whats going on I’ll default to not enough hot liquor… If yer brewing a 5 gallon batch… Dump 8 gallons in, if yer mash-tun holds that much…

I mean I definitely put in more water than I usually do in terms of grain ratio. Here is a photo of the grain after I milled it, just so everyone can see that it shouldn’t have been an issue.

I also ust did a top-to-bottom cleaning of everything and the tubing that leads FROM the false bottom to the output of the tank was super clogged with grain. Unless my false bottom was somehow not seated nicely against the tun bottom, I can’t fathom how this happens unless the false bottom is warped and allowing grain pieces to get underneath. It probably takes… What?.. Like half a handful of grain getting underneath the false bottom to potentially clog the line?


What is the tubing size yer using? Mine is 1/2" ID… I wonder where I put mine… now that I don’t use it…

3/8" ID. Never had an issue before I started crushing my own grain, but that seems like it was unrelated this time

I bet that false bottom is the issue. Try mash in a bag. It should resolve your issue.

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