Grain Under False Bottom While Mashing In

[Duncan83865]

Looking to see if anyone has any advice. My mash tun is a 10gal Rubbermaid round cooler with a basic perforated false bottom from NB. Over the years I've struggled with getting more grain under my false bottom than I'd like--there is a decent pile underneath when I disassemble during cleanup. While sparging, this grain makes its way to my pickup tube, slowing down/stopping the sparge, though it never gets stuck because I can always get it going again after opening the valve slightly to clear the grain. All this grain makes it to the kettle, but I've gotten around it by keeping a paint strainer bag in the kettle while sparging. Basically it causes more babysitting than I'd like.

I strongly believe that the grain is getting forced through the false bottom while mashing in or stirring 15 min before sparging. I always add water first and then grain. Nothing about how I stir seems to prevent it. I have also installed a silicon gasket around the edge of the false bottom (covered on another thread on this site), so I am confident the grain is going through the perforations.

Any thoughts/advice on how to prevent this grain from getting through? For what it's worth, I crush fairly coarse--.036" or so. Thanks!

 

[Gadjobrinus]

Sorry Duncan, you've got me stumped. The two things that came to mind - a silicone rim and your mill fineness - you covered. I don't know the make, but is there a central dip tube, and circle in the bottom? Is that sealed, if so? Maybe try a small amount with water and grain and see if you can see any patterns? Man, sorry, I don't have anything.

 

[Smellyglove]

Seems like you're getting a lot of grains under there.

I have't heard that it's that big of a issue that things are getting clogged. Try tapping hard on the FB to relieve it from any air trapped underneath due to air being released from the water when you agitate it (pouring it in).

 

[day_trippr]

I agree that with the silicone edging done properly the grain isn't going around the FB (bt/dt), and adding strike water before dough-in should help minimize the grains falling through.
If it hasn't been tried, a healthy vorlauf before sending wort to the BK should clear things up nicely.

Cheers!

 

[LarMoeCur]

Some grain pieces will always find away past the false bottom.

When I ran a cooler with a false bottom. I mashed in stirred the heck out of the mash and never stirred again (unless batch sparging). The real key was a good vorlauf to set the grain bed and remove the husks from under the bottom. Make sure you open the valve fully. You want a good pull to set the bed and suck the husk out.

If you're worried about husks in the boil. Put a piece of tubing on the valve and then buy a racking cane filter for the exit end. I

 

[Duncan83865]

Sorry Duncan, you've got me stumped. The two things that came to mind - a silicone rim and your mill fineness - you covered. I don't know the make, but is there a central dip tube, and circle in the bottom? Is that sealed, if so? Maybe try a small amount with water and grain and see if you can see any patterns? Man, sorry, I don't have anything.

Thanks. The false bottom has a hole in the center and then an elbow held in place with a locknut so it should be sealed. From there, it's a compression fitting and copper tube to the valve.

 

[Duncan83865]

Seems like you're getting a lot of grains under there.

I have't heard that it's that big of a issue that things are getting clogged. Try tapping hard on the FB to relieve it from any air trapped underneath due to air being released from the water when you agitate it (pouring it in).

Hmm. If there was air trapped under there, what would be the downside? Just trying to picture what you're describing.

 

[Smellyglove]

Hmm. If there was air trapped under there, what would be the downside? Just trying to picture what you're describing.

the air would make it more "floaty", instead of the weight of it is fully used to sit it at the bottom.. I guess this could only happen when you pour in the grains, if it ever would happen. If you understand. Just a thought, may be far fetched. Or maybe the holes in it is big enough that grains just slip through if they are small enough. A Vorlauf should take care of this. you can do it after doughing in, to set the bed.

 

[Duncan83865]

Some grain pieces will always find away past the false bottom.

When I ran a cooler with a false bottom. I mashed in stirred the heck out of the mash and never stirred again (unless batch sparging). The real key was a good vorlauf to set the grain bed and remove the husks from under the bottom. Make sure you open the valve fully. You want a good pull to set the bed and suck the husk out.

If you're worried about husks in the boil. Put a piece of tubing on the valve and then buy a racking cane filter for the exit end. I

Thanks. Sometime back, I thought I heard stirring a few minutes prior to starting the vorlauf might help with efficiency. I eliminated the boiling water mash out 20 batches ago or so, but figured keeping the 2nd stir might still be worth it. Maybe that's not the case?

Also, I always start the vorlauf with the same slow flow rate that I keep during the sparge and have never thought twice about it, but it sounds like you're suggesting otherwise? I was thinking a fast flow during vorlauf might compact the bed right away?

 

[bbohanon]

I used a bazooka screen in my cooler back when I used to mash in a cooler..the false bottom idea in a cooler always felt too open to getting grains under it when stirring much as you described so I just moved to the bazooka screen option. Worked very well for over 2 years until I moved to large flat bottom SS pots where a false bottom really shines.

You can get a "stubby" bazooka tube that should work in the round cooler if you wanted to give this a go.

Coolers believe it or not will change their shape over time with hot water..sometimes your bottom is not as "flat" as you may think it is (or was originally).

I have a close brew buddy who brews heavily in his cooler and the cooler lining has started to really look rough and and is no where near its originally nice, flat form..He uses a bazooka tube as well due to the lining starting to lose its original shape from heavy hot water use..its more of a "wavy" shape now on the sides and bottom..its like the lining is starting to pull itself away from the insulation...lol

 

[LarMoeCur]

Thanks. Sometime back, I thought I heard stirring a few minutes prior to starting the vorlauf might help with efficiency. I eliminated the boiling water mash out 20 batches ago or so, but figured keeping the 2nd stir might still be worth it. Maybe that's not the case?

Also, I always start the vorlauf with the same slow flow rate that I keep during the sparge and have never thought twice about it, but it sounds like you're suggesting otherwise? I was thinking a fast flow during vorlauf might compact the bed right away?

If you are mixing the mash thoroughly at dough in there is no need to stir again. If the entire grist is wet and mixed well than your efficiency will be fine. With a gravity system there is absolutely no worry about compacting the grain bed. Open the valve fully just be mindful not to drain the too much wort and fill the false bottom holes with husk. Could stick the sparge but that mostly happens from to fine of crush. Most of the time the grain bed will be floating above the false bottom anyway, unless you’re make a very large beer and at your MLT capacity. You want to pull a few pints, pour it back in, pull a full pints, pour it back in, until the wort runs clear. Then set your slower sparge rate.

 

[wilserbrewer]

Some pike to use a BIAB bag to line there mash tun to prevent grain from finding its way through the FB. This also eliminates the possibility of a stuck sparge, allowing finer milling which can lead to higher efficiency. If the mash stick and flow slows, one just needs to lift the bag a bit to get flow.