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High Efficiency Mash Tun : Manifold or False Bottom
I'm getting ready to start larger batches and have come into possession of 2, 1/2 barrel kegs
(thanks to Chuck over at Green Flash) and was reading over this thread on kettle conversions.
http://www.brewingkb.com/equipment/keg- … -3142.html
And recently saw this post on 1n1m3g's HERMS system.
http://www.brewingkb.com/equipment/my-c … -4090.html
Right now I only do 5 gallon batches and I use a 5 gallon cooler for a MT. I made the manifold
from copper tubing, and I'm in the works for creating a newer version in quest for better efficiency.
I'm already getting over 75% efficiency with the manifold I have, but I know it can be better.
I'm just wondering why everyone uses FB's in kegs, instead of a manifold. Is the efficiency better, or
is it just a standard with kegs?
I am currently working on a Keg mash tun with a false bottom. I don't have it up and running yet, but maybe I'll get the pilot batch run next weekend.
I went with a false bottom not for efficiency reasons, but because I wanted to go to a direct fired setup.
With a manifold the grains will be sitting on the bottom of the mash tun and may scorch. With a false bottom its only wort on the bottom being heated (and in my case recirculated). I suspect that is the reason for a false bottom in most keg setups. So don't stress too much over it in terms of effeciency.
I also would put too much stock in your efficiency if you are already between 75-80%. Even if you bump up anothe 10%, what change in your grain cost is it???? $2-$4 per batch, I don't view that as much of a gain to be fretting over. I would be more concerned over consistancy once you have it running. Consistancy rewards you far more times over than, a few dollars in grain cost from increasing efficiency.
brewchez wrote:
I would be more concerned over consistancy once you have it running.
Thanks brewchez! Yeah, it's not really a money issue with grain costs. It's more a consistency thing.
I really like the way the 5 gal igloo holds heat, it's just not able to do more than 13-14 lbs. And it seems
when I try to mash more grain for a high OG, my efficiency goes down. But I can consistently mash 10lbs
for an OG over 1.050... just looking for more options.
I like how 1n1m3g's MT is wrapped in a hot water blanket, but didn't see how the top holds the heat. 10 gal
igloos are only $60 from Target, so I'm kind looking that way and just use the kegs for boil pot and HLT.
Unfortunately, one of the kegs is an aluminum Newcastle keg while the other is a stainless keg, but has the
rubber top and bottom... but can't beat it for $20!
The only reason I went with a false bottom over a manifold is because I already had one from when I turned by 6.5 gal bucket into a MT.
I think that at the scale on which homebrewers make beer (usually 5-10 range) is small enough that the type of MT you have or false bottom vs manifold really won't make a difference with the efficiency of extraction during a mash. Professional breweries have to take MT shape and manifold shapes into considerations because they area working on such huge scales that terms such as vector flows in the sparge start to become an issue. As homebrewers we use such small vessels that these issues become negligible.
Things that will increase extract efficiency include doing a mashout by raising the mash temp close to 170F, the time you take to do the sparge (the slower you go the more chance you give residual sugars to dissolve into the sparge water), and the temp of the sparge water (the closer you can get to 170F again the more chance you give residual sugars to dissolve).
As Brewchez says, you just need to get your system dialed in and once you find that groove you'll be able to achieve consistency, which is the most important part of brewing. Cheers!
d4pivo wrote:
10 gal igloos are only $60 from Target, so I'm kind looking that way and just use the kegs for boil pot and HLT.
Check out your local Home Depot. They were selling 10 gallon round Rubbermaid coolers this summer for less than $40 bucks. They might still have a few left kicking around somewhere. I picked up one to use as a HLT and use one for my mash tun as well.
FirePitBrew wrote:
Check out your local Home Depot. They were selling 10 gallon round Rubbermaid coolers this summer for less than $40 bucks.
Thanks FirePit! Stopped by today after work and picked one up. I was looking there before, but never found one, so I got a 5 gal round from Lowes for under $25 -which I use as a MT now. I'll continue to use that and the new 10 gal as a HLT... until I get my new kettle made from the keg.
I like Thirsty's idea of using a sawsall to cut out the top of the keg
-just wish I could replace the "I" with "my dad" like he did 
d4pivo wrote:
[I like Thirsty's idea of using a sawsall to cut out the top of the keg
-just wish I could replace the "I" with "my dad" like he did
It was a shitload of work and he went through a couple sawzall blades- but it was definitely woth all of the eh, eh, effort. 
thirsty wrote:
It was a shitload of work and he went through a couple sawzall blades
I bet! I've seen some videos of guys trying to use a dremel cut-off blade, and that's just ridiculous.
I've thought about, and known guys who used just a hand grinder, but couldn't get as close the
side wall.
The sawsall is a great idea, and with the right blade(s) ... it should go ok.
Also thought about a plasma cutter, but figured the splatter wouldn't be so good for the inside. But it's not as bad as oxy-acetylene.
Anyone have any concerns or comments about using an aluminum keg for heating sparge water?
d4pivo wrote:
Anyone have any concerns or comments about using an aluminum keg for heating sparge water?
No concerns really. I have a buddy who has a 20 gallon rig consisting of three 30 gallon aluminum pots for his hot liquor tank, mash tun and kettle. The only thing he's complained about was making sure to rinse Oxyclean/PBW out well and make sure there's none left in the bottom of the kettles after cleaning because it'll pit aluminum.
d4pivo wrote:
I bet! I've seen some videos of guys trying to use a dremel cut-off blade, and that's just ridiculous.
I used an air tool dremel. In my opinion, the best option. Went through 1.5 wheels, nice clean cut. An electric dremel wouldn't have the power but if you have access to a nice air tool, you're golden.
Plasma would work nicely I would think. I used to use one at my old job and the cut was always very clean with little to no splatter. Acetylene torch would probably be a lot more trouble than it's work, IMHO.
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