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-   -   false bottom for direct-fired recirculation mash? (http://www.homebrewtalk.com/f36/false-bottom-direct-fired-recirculation-mash-46920/)

billtzk 12-04-2007 08:22 PM

false bottom for direct-fired recirculation mash?
I'm building a direct-fired recirculating mash tun out of a 15.5 gallon sanke keg (part of my Brutus Ten clone project that is now underway) and I'm trying to decide what type of false bottom to use.

I know some people use copper and SS-braid manifolds in their mash tuns. Others use the stainless 10 to 15 inch diameter perforated stainless "disk" type false bottom with the pickup tube that goes down to the bottom of the keg through a hole in the center.

I'm inclined to go with the full perforated SS disk false bottom because it will keep the grain from direct contact with the bottom of my direct-fired mash tun. An SS-braid won't do that. I know that there are experienced brewers (e.g., BrewPastor, Monster Mash, to mention a couple who posted pics that I found while searching the forum), who use a SS braid, but I don't know how they heat their mash.

Which solution is likely to work best for a direct-fired mash?

EDIT: Price is not a factor. My DIY time, however, is very valuable as I'm spending a lot of time already to build my brew stand. I don't want to spend my time on a DIY solution (e.g., ss-braid / copper manifold) unless it is likely to be significantly better (less chance of scorching, higher yields, less likely to get stuck) for my direct-fired mash.

Lil' Sparky 12-04-2007 08:25 PM

I use a FB, but it doesn't cover the entire bottom. I imagine the full FB may allow the most even temps across the grain bed, but if you're recirculating, it probably doesn't make much difference. You're constantly pumping out the hotter wort while the cooler wort drains down. I think the key is heeping the heat low and slow. Here's a pic inside my MLT FWIW.


billtzk 12-04-2007 08:34 PM

Nice setup Lil' Sparky. Looks similar to this one that I was thinking about from Midwest - 11" Stainless Steel false bottom - for Sanke Keg. It's a little larger in diameter than yours appears to be, and it is inexpensive. Comes with a pickup tube.

Lil' Sparky 12-04-2007 08:38 PM

I think mine's only 9 or 10 inches. I don't have any complaints and it's worked fine for a direct-fired MLT. I've been recirculating for a few batches. Before that I just stirred while the heat was on. Worked fine, just more labor-intensive.

If you get that, here's a head's up. Put a hose clamp on your pickup tube to provide pressure against the FB to keep it tight against the bottom. If you get grains by the sides it's a stuck sparge and you'll be scooping your grains out. Ask me how I know. ;)

Lil' Sparky 12-04-2007 08:41 PM

You should also post some pics of your stand as you're building it!

billtzk 12-04-2007 09:37 PM

I am documenting the build of my Brutus Ten clone at each step and I'll post when I'm done. I'm pretty much following the description and parts from the BYO article last month.

I'm at stage 0.5 LOL. I have the metal sitting on my porch and I have about two-thirds of the various parts ordered. I'm expecting shipments from morebeer, cole-parmer, and mcmaster carr this week. I got the ASCO red hats on ebay and the burners from some place in New York. I'm using natural gas, not propane. I got the gas line to my back patio run a couple of weeks ago.

I've cut the stock on a chop saw. I should have bought a horizontal band saw cuz the chop saw doesn't make perfectly straight cuts. Oh well, I think I can dress it up with a hand grinder. I'm practicing welding on scrap right now. I'm just learning how to weld and I need more practice for sure. My welds look pretty bad.

I'm building my Brutus Ten clone from mild steel since stainless is too pricey. Meanwhile, I've got kegs and most of the parts to build the HLT and MLT and I already got a boil keggle.

Lil' Sparky 12-04-2007 11:44 PM

Very cool. I plan to build a non-automated single tier stand this spring. I've had my 3-tier stand for a while, but I really like the idea of having everything low and accessible.


ebeer 12-05-2007 04:45 AM

I too mash in a converted keg, ss false bottom, with direct heat and recirculation. I love this setup....step mash, mash out, & constant mash temps are relatively easily achieved (sure you're well aware if this is the design you're going for).

WRT to the false bottom, I would choose one that is flat and with out handles. Some options are domed, and some have handle welded on. This makes it harder to dough-in. My setup looks much like the one above, there is already a pick up tube and thermometer in the way when stirring the grains with a paddle. You can get around them pretty easily, but the addition of a handle would be cumbersome IMO, and a dome would make it hard to get a paddle on the sides.

The very best setup I've seen for this is a bottom valve. He drilled a hole dead center in the bottom of the keg, then a 90 degree ss elbow was welded on the outside bottom of the keg, with a long ss nipple and ball valve on the end. You have to cut a hole through the bottom skirt for the nipple, but it works really well. False bottom sits on top as show above, but there's no internal pick up tube. *If* I ever redesign my mash tun I'll prolly do this.

SuperiorBrew 12-05-2007 05:27 AM


Originally Posted by billtzk
Nice setup Lil' Sparky. Looks similar to this one that I was thinking about from Midwest - 11" Stainless Steel false bottom - for Sanke Keg. It's a little larger in diameter than yours appears to be, and it is inexpensive. Comes with a pickup tube.

Thats what I use with direct heat and recirculation. I have a hose clamp above it and below it and keep it pressed tight to the bottom so nothing gets under it.


talleymonster 12-05-2007 05:45 AM


Originally Posted by billtzk
My welds look pretty bad.

I wouldn't sweat how your welds "look". As long as you get good penetration and have little to no pitting, you'll have a sound enough weld for what your doing. And if you're going to really focus on cosmetics on the Brutus Stand, you may want to grind down the welds when you finish to make it smooth and give it the appearance of one continous piece of metal.

But, if you are going to make the integrated gas chamber in the frame like the one in the recent BYO issue, then those welds will need to be a little more precise. You'll need strong solid welds so that no gas leaks out.

What kind of welder are you using? If you are an inexperieced welder, a wire-feed would be the way to go. A wire-feed takes little practice to be able to lay down a decent weld. Even better if you can get ahold of a MIG welder. You'll get cleaner welds. A stick welder is a little more difficult for a beginner because of the constant shortening of the welding rod (electrode). You have to consistently adjust your distance from the work to compensate for the rod burning up and getting shorter.

If you have any welding questions I'm sure Yuri could help you as well, along with a few others.

Good Luck! We'll definitely want to see some pictures!:rockin:

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