False Bottom 10 Gallon Cooler Woes

I'm having some problems with my current mash tun. I use a 10 gallon home depot cooler with a false bottom (pictured below). The issue is no matter how much I vorlauf, I can't keep big chunks of grain out of my runnings. I've resorted to using a very finely meshed strainer to catch the grain before it reaches the boil kettle.

It appears a lot of people use this setup with success, but it doesn't seem to be working for me. I've used up to 13 lbs of grain, so the weight of that and the water should be enough to keep the false bottom in contact with the bottom of the cooler. It doesn't look like the plastic is warped at all either.

I'm all ears for any suggestions to help with this. I'm thinking about adding something heavy to keep the false bottom flush against the bottom, but I'm not sure what would work best. Any help is greatly appreciated.

My false bottom is a tighter fit in my cooler. I have never had any problems. It looks like you have some extra space that might allow grain to get under.

yeah the space around the false bottom seem to be the culprit. i figured the weight of the grain would be sufficient, but it's not doing the trick. i feel like there has to be something i can add to keep the cooler flush with the bottom. Something heavy.... I've tried cutting a piece of tubing to serve as a gasket, but no luck

I have a very similar setup as you with the same issue. 10 gal Rubbermaid cooler with a MoreBeer 10 gal cooler false bottom. I've only brewed two batches on this system so far, but I was unimpressed with the amount of grain I was getting even after vorlaufing 2+ gallons of the mash. I've never used a domed perforated false bottom before but figured it would filter grains a little better. The fit on mine is just like yours. A little bit of wiggle room around the edges.

The other system I brew on uses a DIY copper manifold for the false bottom. It's octagon-shaped with tons of Dremeled slits on the bottom. Why I didn't just build another one like that is beyond me. You pretty much don't even need to vorlauf at all. Runs clean right out of the gate. Perhaps that's a project in both of our futures.

I do have one question that I am curious about. When setting the grain bed with the domed false bottom, do you open the valve full-bore or just partially? With the copper manifold, we don't worry much about properly setting the grain bed for filtering purposes. It works like a charm regardless of a partially-opened or fully-opened valve. Brewing my inaugural batch, that very question ran through my head. Coupled with the poor filtering I was experiencing, I wasn't sure if fully vs partially opened valves set grain beds differently.

fwiw, here is what I did to deal with the fb fit issue.

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I should probably update that thread to note this mod worked great...

Cheers!

Just like you, I never really had the issue with the stainless steel braid i used before this! I switched to the false bottom b/c I intend to use a pump in the near future. A false bottom seemed like a better option.

To answer your question, I haven't regulated the flow on the ball valve much. Originally I opened the valve slowly and gradually increased the flow, but it doesn't seem to matter much. Now I just open it fully from the beginning. Both methods yielded the same grainy result for me.

day_trippr said:

fwiw, here is what I did to deal with the fb fit issue.

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I should probably update that thread to note this mod worked great...

Cheers!

Click to expand...

What did you use to seal that up? I can't quite tell what the red is.

Check the linked thread, and if you still have any questions please ask away!

Cheers!

mgohring said:

What did you use to seal that up? I can't quite tell what the red is.

Click to expand...

Check the link... day_trippr provides a the part number from mcmaster.

Question day_trippr: Does the gasket actually create an airtight seal? Also, how did you attach the cut edges?

Looks promising!

I guess it would help if I could read! Totally missed the link the first time through. Thanks day_trippr!

Does the gasket actually create an airtight seal? Also, how did you attach the cut edges?

Click to expand...

The seal is pretty darned effective - nothing's going to get between the gasket and the cooler liner, or the gasket and the fb. Everything is under tension.

And there's nothing there but the silicone gasket and the fb - and careful cutting of the gasket length (I snuck up to the eventual right length). The ends butt tight together, and the rest is pretty much just geometry and physics working

No glues or cements or anything. Just silicone and stainless steel, stuffed into some kind of poly-razzmatazz plastic liner...

Cheers!

Nice find on the silicone gasket! I'm pretty sure I'll be doing this to my fb.

I tried a false bottom and a kettle screen, both were more problematic and less efficient than the cheap SS toilet supply line braid, which I have now gone back to. Solid efficiency (70%), no stuck mashes, vorlauf a quart or less for clear wort.

g-star said:

I tried a false bottom and a kettle screen, both were more problematic and less efficient than the cheap SS toilet supply line braid, which I have now gone back to. Solid efficiency (70%), no stuck mashes, vorlauf a quart or less for clear wort.

Click to expand...

I've heard of many brewers using those on the 5 - 10 gallon scale with pretty good success. Our other system is designed for 20 gallon batches and I feared the stainless braid collapsing under 30-40 lbs of grain, so we opted for the copper manifold. It filters great and we typically hit about 90% efficiency!

mgohring said:

I've heard of many brewers using those on the 5 - 10 gallon scale with pretty good success. Our other system is designed for 20 gallon batches and I feared the stainless braid collapsing under 30-40 lbs of grain, so we opted for the copper manifold. It filters great and we typically hit about 90% efficiency!

Click to expand...

If you are getting 90% efficiency, your crush is too fine or you math is wrong. That is nearly impossible with an optimal crush, and really not something to shoot for, as you risk tannin extraction at those levels.

65 - 75% efficiency is really optimal for the hoembrewer.

g-star said:

If you are getting 90% efficiency, your crush is too fine or you math is wrong. That is nearly impossible with an optimal crush, and really not something to shoot for, as you risk tannin extraction at those levels.

65 - 75% efficiency is really optimal for the hoembrewer.

Click to expand...

Too fine of a crush, possibly, but with almost stuck sparges over the last two years it seems to be ok. Even hefes using 50/50 pilsner and wheat with no rice hulls lauter just fine. I've never noticed any tannins in the final beer that have made me want change our process. 90% isn't where we are aiming, it's just where we typically end up.

Do a little looking around on here and you'll find a lot of people are around 90% efficiency. I see many of them are using a manifold type false bottom as well, not that you have to get those numbers. I've even seen a few brewers on here hitting 90% going the BIAB route. So, it's not as impossible as you might think.

I've heard Jamil say that he likes to target 70% on his beers, especially some of the maltier beers. I think the "optimal range" is more of a personal preference and not a fact. Tannin extraction is a real thing, yes. Thankfully, I've not noticed it in my beers at the efficiency we're getting, so count me lucky!