False Bottom For Keg Mash Tun

[BeerSwiller]

Hi Guys,

Been looking alot over the net trying to work out the best way to go about making a false bottom for the bottom of the keg.
I have seen ones at craftbrewer but they only seem to be 300mm diameter which will not cover the bottom of the keg completely.
I have been thinking about making one up but thought id ask here for some pictures/ideas which might be better than what i've read about so far.

From looking at the standard CUB keg, id say the diameter would need to be about 370mm

 

[argon]

I have one from CB and it does not cover the entire area of the keg... but that doesn't matter. I batch sparge and I typically get 85% extraction efficiency, can run off as fast as possible and have never had a stuck sparge, even with greater than 20% rye. The pickup tube goes right to the bottom of the keg, giving me zero dead space, meaning i get every last drop out of the tun.

 

[BeerSwiller]

I have one from CB and it does not cover the entire area of the keg... but that doesn't matter. I batch sparge and I typically get 85% extraction efficiency, can run off as fast as possible and have never had a stuck sparge, even with greater than 20% rye. The pickup tube goes right to the bottom of the keg, giving me zero dead space, meaning i get every last drop out of the tun.

Thanks for the info, does the false bottom move much since it's not actually held in place? If your getting 85% eff then that's good enough for me

I think from memory the cb type is actually domed in shape and not flat? Is that right?

 

[argon]

They sell both flat and domed... i have a flat one that site over the domed portion of the bottom of the keg. The pickup tube is stainless pipe that rests on the bottom of the keg, in the middle of the false bottom, which is just kept in place by the weight of the grain... doesn't move at all. When i empty the grain, all i do is tip up the keg and the false bottom comes away from the base and i'm able to clean under it.

 

[Malted]

Hi Guys,

Been looking alot over the net trying to work out the best way to go about making a false bottom for the bottom of the keg.
I have seen ones at craftbrewer but they only seem to be 300mm diameter which will not cover the bottom of the keg completely.
I have been thinking about making one up but thought id ask here for some pictures/ideas which might be better than what i've read about so far.

From looking at the standard CUB keg, id say the diameter would need to be about 370mm

I think it relates to finding a lid for the mashtun.

A lot of folks don't cut the whole top off the keg so that it makes it easier to find a lid to fit. Therefore the hole in the top is smaller than the diameter of the keg and consequently, so that they can get it in and out easily, the false bottom is also a smaller diameter than the keg.
Even with nicks in the ring of the keg top (as per photo below) you still need a false bottom smaller than the keg. You turn the flase bottom vertical to pull it out through the nicks.


The other option is to just cut the entire top off but this is favoured more for keggles because they don't need a lid.




Having said that, I have now made a mashtun with the entire lid chopped off (as per the keggle) because it is easier to get the spent grain out. It is now on a brewstand and I am bottom draining it. I haven't worked out what I will do for a lid though...

 

[Wolfy]

Having said that, I have now made a mashtun with the entire lid chopped off (as per the keggle) because it is easier to get the spent grain out. It is now on a brewstand and I am bottom draining it. I haven't worked out what I will do for a lid though...

The hole in the keg is in the base of the keg?
... with a tap placed where?

 

[Pollux]

I have a dome FB from CB in my mash keggle. Works perfectly for me on my pump driven system.

Only issue is that I originally cut the top of the keggle to fit the size of a spare lid I already had, so getting the FB in was impossible as the hole was too small. Two slots opposite each other at the opening make it easy to slide the FB in sideways, then lay it flat and connect the silicon hose to the nipple on the inside.

If I remember I'll take photos next time I am looking at it.

 

[1975sandman]

I have a keg as a mash tun as well with bottom draining........just have the tap straight up and down with an elbow attached.

Have good drainage! B)

 

[booargy]

 

[booargy]

and the other part

 

[hsb]

nice false bottom/shield!
My domed FB keeps inverting, think i may be recirculating a bit too quickly. As it is, ive just been reversing the fittings and running it upside down each time.
The weight of grain definitely keeps it in place. Ive been considering something much smaller like an adapted SS teapot insert. I run mine up through a pickup but bottom draining is a nice touch if you can manage it.

View attachment 47986

 

[Malted]

The hole in the keg is in the base of the keg?
... with a tap placed where?

Yes. Pipework runs out so tap is horizontal under edge of keg.
Lots of different ways of doing it, that's just the way I chose...

Edit: picture of mashtun is mk1, I am referring to mk2

 

[Malted]

and the other part
View attachment 47988

Nice falsie! You're pretty scmick with the angle grinder/dremmel.
So you cut the bottom out to make the falsie?
You then have welded a rod in place of the spear dip tube to hold down the falsie?
Have you left the ball valve in place on the spear top, or do you bottom drain out the spear top (i.e. where the valve was and where your hand is in the photo).

I suspect you bottom drain from underneath through where the ball valve used to be. Can you show a photo of that part where your fingers are? What fittings have you put into that part of the old spear assembly?

 

[booargy]

I have just welded half a compression fitting in. I plan on turning up a fitting to go in there with a BSP thread. This will then be welded in. It was only so I could use it for a batch.


It is plumbed similar to this but with a valve. eventually I will have a 3 vessel 3 pump system. then this valve won't be needed just a drain valve.

 

[Malted]

I have just welded half a compression fitting in. I plan on turning up a fitting to go in there with a BSP thread. This will then be welded in. It was only so I could use it for a batch.

It is plumbed similar to this but with a valve. eventually I will have a 3 vessel 3 pump system. then this valve won't be needed just a drain valve.

Cheers for the picture of the top.

And without the spring the spear top goes in tightly and seals?
Why three pumps?

Looks like it needs to go in a build thread so we can see more!

 

[booargy]

Cheers for the picture of the top.

And without the spring the spear top goes in tightly and seals?
Why three pumps?

Looks like it needs to go in a build thread so we can see more!

the spring only holds the spear in. but a lip is needed to hold the seal so the fitting isn't cut right down.

I have purchased two 815-c but I want a bigger pump for the kettle. this will give me 3 separate systems. which will make cleaning and back to back batches easier. and because I can

 

[BeerSwiller]

Thanks everyone for all the info, just wondering what difference it would make using flat or domed type... I was thinking I might just grab one from craftbrewer but not sure why theirs is more expensive than the same type that beerbelly are offering?

 

[Malted]

Thanks everyone for all the info, just wondering what difference it would make using flat or domed type... I was thinking I might just grab one from craftbrewer but not sure why theirs is more expensive than the same type that beerbelly are offering?

As mentioned by hsb, I too had problems with my false bottom inverting or just one side lifting and allowing grain through. This is why I have gone for the system I have with the FB being able to be screwed into position. I think a domed false bottom is likely to be a bit stronger or resistant to flexing/lifting at the edges.

If you had a flat bottomed pot for a mashtun you wouldn't want a flat false bottom unless you had something for it to sit up on (like little legs for instance) or just take the easy option and put a domed one in it. A flat false bottom would be ok for a domed bottom pot (or keg) but would need to be of a thicker material to have the same resistance to flexing.

Price difference? CB used to sell BeerBelly made false bottoms but it was my observation that supply by BB was random; I reckon CB have sourced them from someone else who charges them more.

Edit: had to fix a spelling mistake

 

[Malted]

The hole in the keg is in the base of the keg?
... with a tap placed where?

Mashtun mk2: I just used what plumbing bits I had at hand. Easy to flip the tap over if I find there is not enough room to get my hand in onto it, or put a longer piece in between the welded socket and the elbow, or flatten the handle.


With a shorter temperature probe (or an electronic probe under the falsie) there would be little to catch the mash paddle as the mash is stirred. That is part of what annoyed my about the previous mashtun having to stir around a pipe that came over the top of the false bottom from the tap. That and it was a PITA to remove the pipe and falsie for cleaning.

 

[BeerSwiller]

Does anyone know If the false bottoms from craftbrewer are the same thickness/strength as the morebeer/grain and grape version?