15 gal poly MLT project - False Bottom?

I am buying a 15 gallon poly water container to use as an MLT. I will be cutting the top off and fashioning a removable top.

I am wondering how to install a false bottom with this setup, being that there is no concave bottom or ridge to install against. thx

cbird01 said:

I am buying a 15 gallon poly water container to use as an MLT. I will be cutting the top off and fashioning a removable top.

I am wondering how to install a false bottom with this setup, being that there is no concave bottom or ridge to install against. thx

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Jaybird makes false bottoms for coolers that come with a stand because of that reason. You should measure your inside diameter and go shopping at http://www.norcalbrewingsolutions.com/. Think he's also still offering free shipping but not positive.

If the bottom of that vessel is flat, you could use a domed FB...

Cheers!

ok, so then it is cut to order. Makes sense

Wow, pretty pricey. What's my other options? Can I do a manifold, without creating channeling?

i like that container. manifold is your most economical solution. make one that is big enough, and channeling shouldn't be too much of an issue

and what is your plan for insulation or maintaining heat? recirc/electric?

You could use a mash screen like this one:

https://www.homebrewtalk.com/f51/55-gal-drum-mash-tun-false-bottom-ideas-138941/#post1575665
Several good ideas in that thread.



In my 50 gallon system I use a loop of silicone tubing connected with a piece of 1/2" OD stainless tube to hold up a stainless false bottom I made.

pinback said:

i like that container. manifold is your most economical solution. make one that is big enough, and channeling shouldn't be too much of an issue

and what is your plan for insulation or maintaining heat? recirc/electric?

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I am an insulation guy, so I have materials available. I plan to use polyurethane spray foam insulation. We have 200 bd ft kits, which are for contractor use and much better application than the can stuff(which doesn't really apply well to a large flat surface area). I plan to add 1 inch, which will give me an R-5. I am going to test it and see if that is satisfactory.

I may add a layer of reflectix over that if needed. The thing I see people miss is that Reflectix has a very small R-value. The air space in the bubbles is actually only R-1.1(from conduction). The only way you get a value from it is if you are somehow stopping RADIANT heat transfer. In order to stop radiant heat transfer (which is heat transfer across an air space), you MUST have an air space. It barely helps if you wrap a MLT in Reflectix without an air gap. That air gap must also be air tight. So, I will install 1/2in furring strips around the foamed MLT, then a layer of reflectix. This will then be reflecting the radiant heat transfer from the heated up foam back to the MLT. The key is that air gap must be air tight, or Convection will ruin the whole gain by the Reflectix application. So, I will be sure to tape the seams well and have a space at the top, which is uninsulated so the tape can adhere.

BargainFittings said:

In my 50 gallon system I use a loop of silicone to hold up a stainless false bottom I made.

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What do you mean by a loop of silicone, you mean high temp silicone tubing, or silicone caulk? How much room do you need under the false bottom?

Where is a good source for the material to use for this. Also, how do you cut the circle with significant accuracy to prevent grains bypassing?

I use a loop of 1/2" x 3/4" silicone tubing we sell under the false bottom to act as the seal.
A short piece of stainless steel tubing connects the two ends.

The false bottom is not tight against the side.


I don't direct fire the vessel so the silicone tubing works well to keep the grain from getting under the false bottom.

Like the silicone idea. Thanks

BargainFittings said:

I use a loop of 1/2" x 3/4" silicone tubing we sell under the false bottom to act as the seal.
A short piece of stainless steel tubing connects the two ends.

The false bottom is not tight against the side.

I don't direct fire the vessel so the silicone tubing works well to keep the grain from getting under the false bottom.

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Do you just use the pressure of the grain bed compaction to push down against the silicone to prevent grain blow by or some other method?

How about using a dome false bottom - http://www.homebrewstuff.com/12-domed-false-bottom.html to sit flat on the bottom? I only find 12 inch and I have a 15 inch diameter, but it seems like it would not matter since it is sitting on bottom anyway.

Is this Craig in Tucson? If so, I have some leftover perforated SS from making my FB. It's ~16" by 20", and you're welcome to have it if you decide to use the silicone tubing method. The holes are spaced a little further apart than ideal IMO, but I haven't had any issues with drain speed or stuck sparges. Here's what mine looks like-



I also have an extra 50' roll of 1/2" ID silicone if you need some.

I would think a 12" domed FB would work fine too. I've seen them used in larger vessels without issue before.

Dang...wish I was Craig in Tucson!

The false bottom and malt press against the tubing and forms a seal.

awesome, thanks ross. I think I might take you up on that. what do you all suggest as a dip tube assembly? I am not too keen on the silicon tubing to the bulkhead method.

No problem, and this is Jason, not Ross. It's in my shop up at my parents house, but I'll grab it next time I'm up there, and we can meet up more central sometime.

As far as diptubes, I don't have any since I bottom drain, but I made a copper diptube for a fellow homebrewer, and he seems happy with it. It's essentially the same design as Jaybirds, but made of copper instead of SS, and with a small shoulder that holds the FB down. It was pretty cheap and easy to make.

Jason! That is funny, I have been talking to another brew bud in Tucson and never knew what his screen name was and thought it was him...Excellent, thanks Jason, I will get in touch. It will really help the project. Can you PM your phone? Talk to you soon.

Wow dude! You have a lot of posts for a three year stint!

50 feet of silicone and an extra 16 inch piece of stainless perf...what the heck did you build?!

cbird01 said:

50 feet of silicone and an extra 16 inch piece of stainless perf...what the heck did you build?!

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Ha! Just a ghetto 3 keggle HERMS. The perf SS I got from the scrap pile at a local metal yard. I think I paid either $5 or $10 plus a sixer of homebrew for a pretty large piece. The silicone is a long story.