Mash Tun Question

Hi All,

I've gone all over the internet and can't seem to find anyone with my issue, so I pose it to y'all...

I recently got into all grain. Bought a 5 gal round cooler MLT with a false bottom. With both of my all-grain attempts, there is almost no flow out of the tun. I've tested with water and all flows well. I've blown back into it and nothing's clogged, but for whatever reason the flow out is a trickle at best.

The only thing I've been able to do to get some flow is take my stainless spoon and press on the hose that goes from the false bottom to the ball valve. Usually once I curse at it and move the spoon around enough I start getting a little flow. Once, it actually flowed out quickly, but as soon as I batch sparged it was back to the same old tricks, even with no change to the grain bed.

Everytime I've run into this I've tried to remedy by emptying out all of the grain into a bucket, try and clean out the tun in case there was some issue I couldn't see, and try again. Haven't tried the beers that have been done this way so we'll see what kind of effect that had.

The only other thing I could see causing this is a siphon problem, but I have a hose clamp on the hose on the outside of the tun, and during one of my 'empty and start over' phases, I put a clamp on one end of the inner hose (maybe I should have one on both ends??).

I'm thinking of just giving up and buying a bazooka screen to replace the false bottom, but before I do that, I'd really like to hear if anyone thinks I'm missing something. Thanks!

Obviously, if it is flowing great with just water, but not with grain, there is some sort of clogging issue.

You do not want the mash to flow too quickly, but you describe it as a trickle, so there is a problem.

My first suggestion, and something I learned from early AG brewing was, a hose attached to the valve on your mash tun will create a nice suction which will help the flow and getting as much wort as possible.

With this potential clogging, you may want to look at your grain crush. It may be too fine. In that case, you could use some rice hulls or just crush less. Others, I'm sure, will chime in with their experience or suggestions. I use a SS braid and not a false bottom.

How much space is under the false bottom? I'm just wondering if it would help to lift it up off the bottom of the MT some, you may need to adjust your mash volume a small amount to account for the extra space but sometimes it helps.

I switched from a false bottom to a bazooka screen and couldn't be happier. Only used the false bottom once and instant stuck runoff. After I was done I examined the false bottom and saw it doesn't sit flat so grain was easily getting underneath.

With the bazooka screen I never have a stuck runoff or sparge, the only single time I had a slow (not stuck) runoff was when I did a pumpkin and used too little ricehulls. And the bazooka screen was significantly cheaper.


Rev.

IME, bazooka screens (or that style) work really well in cooler mash tuns. I have a false bottom in my keggle mash tun, but I wouldn't go for a false bottom in a cooler.

If the hose connecting the false bottom to the ball valve isn't strong enough, it can be getting compressed and cutting off the flow of wort. Combination of weight and the hot wort could be doing this.

Post up some pictures of the setup so we have a better idea of what [exactly] you have there.

Golddiggie said:

If the hose connecting the false bottom to the ball valve isn't strong enough, it can be getting compressed and cutting off the flow of wort. Combination of weight and the hot wort could be doing this.

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This was my first thought also. Hot water making the hose more loose and pliable and then the weight of grains and water causing a twist or pinch in the line.

What kind of line are you using from the valve to the false bottom?

Maybe shortening the line if possible or switching to a more rigid plastic tubing just might do the trick

I have a section of 1/2" OD stainless tubing connecting the false bottom to the ball valve (all provided by NorCal/Jaybird)... No issues due to temperature, pressure, etc, and I don't have to worry about it [ever] discoloring or becoming brittle on me. I've custom bent tubing for both my one hardware, and others (I have a bender). As long as I have a piece long enough, I can make whatever I need.

Golddiggie said:

If the hose connecting the false bottom to the ball valve isn't strong enough, it can be getting compressed and cutting off the flow of wort. Combination of weight and the hot wort could be doing this.

Click to expand...

I used a standard piece of tubing for a long time running from my HLT to the MLT and it would always collapse under the heat. Now I have some nice thick heat resistant tubing and it is wonderful!

Rob_E, I've been having the same problem ever since I switched to a false bottom. Unfortunately, I haven't found the answer yet.

I don't think crush has been a problem as like you after emptying the mash into another bucket and dumping it back in again there are no flow problems. I also have the re-enforced tubing, the stuff with the string in it, so I don't think the tube is getting smashed.

I suspect grain is getting under the false bottom and clogging the hole. Golddiggie has a good suggestion of using a hard pipe instead of tubing. I know Adventures in Homebrewing uses a similar setup in the false bottom kits they sell.

Thanks for all the replies everyone. In believe there is enough space under the false bottom. I don't think a clog is the entire problem, although it could be happening. The hose from the false bottom is hi temp silicone which may be compressing since it is pretty pliable, and since it seems pushing on it with the spoon helps (as far as I can tell since I can't see it with grain in there). All that said, I think I'm just going to get a bazooka screen. $16 seems a lot easier than trial and error with a new hose and more brews and possible frustration, I'll update with the final decision in a couple weeks when I free up a fermenter.

I'm also very curious how that last IPA turns out after all the issues with temp, grain, etc. For some reason I think it'll turn out great so we will see. NB Dead Ringer, for the record.

How far does the hose extend past the false bottom? Have you thought about the weight of the grain pushing down on the false bottom which will cause the end of the tubing to go down against the bottom of your kettle causing the flow to stop or trickle?

Garyr2973 said:

How far does the hose extend past the false bottom? Have you thought about the weight of the grain pushing down on the false bottom which will cause the end of the tubing to go down against the bottom of your kettle causing the flow to stop or trickle?

Click to expand...

That's possible too. Although the more I think about it, the more likely it's the hose from the bottom to the ball valve getting crushed. It's hi-temp silicone, which is pretty soft. It would also make sense, since it seems pushing on the side of the hose is what gets a flow started (albeit slowly). If it was getting crushed, pushing on the side might restore the shape and help the flow. I have some extra tubing so I may try that. I just hate to go through this again if it's not the cause. But I can't think of another way to test except with grain...

I brewed this weekend and for the first time with my false bottom didn't have a stuck/slow sparge. I did everything I normally do and even forgot to add rice hulls. The only change I did was to take a length of tubing and slice it length wise. Using the slice tubing I lined the false bottom. I read a thread that mentioned that a vacuum could cause a slow/stuck sparge. Some of the suggestions included using a funnel and pouring water in through the valve to get the trapped air out or raising the false bottom off the floor of the cooler. Since I had extra tubing I tried raising the false bottom.

After my mash I turned the valve and it flowed perfect. Not even a hint of a stuck/slow sparge. I am not sure if I was lucky or if this will fix the problem but wanted to share my successful mash this weekend.

Glad to hear thing went well! Brew on my friend!

Ok, I am finally about to have a free fermenter, so I've been pondering my initial questions and your answers for about three weeks now.

Went up to AHS (so lucky to have them right up the road) and I was about to buy a bazooka screen in case it all went wrong again. When I told the guy my issue, he said he used to have the exact same problem. Told me to put the screen back and he grabbed a 10 gal nylon bag to line the tun with. He said as soon as he started using that he's never had an issue. It makes a lot of sense since it's another method of filtration rather than just relying on the false bottom.

I was originally going with the thought that my hose was getting crushed, but upon further inspection I just don't see how that would be possible since I have a hard time fully crushing it myself (it's only a 5 gal tun).

Anyway, as the guy at AHS said, if it gets stuck, just lift the bag out and it should be good to go.

I'll update after I brew on Saturday. Here's to me not cursing the hell out of my choice to go all grain! (not that the cursing lasts for long, of course)



Thanks again y'all.

Ok, finally updating this.

So it seems the issue all along was actually stuck sparges, as far as I can tell. The nylon bag trick worked like a dream! So much so that I ran off way too fast in the first brew, resulting in low efficiency. Brewed again on Monday, took my time, and hit 80% with no flow issues whatsoever. So glad I didn't have to swap out the false bottom since it works so well now. The only issue I ran into initially was the bag falling in, getting wrapped around the mash paddle, etc, but you get used to it.

Thanks for all your ideas!