SS Keg for fermenter

[raven_r_one]

Hi all -

I've been searching around and I'm desperate to replace my collection of 6 gallon brewing buckets with ONE large fermenter capable of holding 10 - 12 gallons.

I've managed to get my hands on a supply of kegs, and thinking I'm going to turn one into a fermenter.

I'm thinking of doing this inverted - where the filler neck is at the bottom. Thinking I'd build a stand so I can gravity feed my still, and yes - I realize that means a pump from the mash pot to the fermenter.

I'm thinking about a SS female quick disconnect that leads into the top of the keg, a valve to keep the opening closed, and potentially a thermowell.

With the keg inverted, and the need to clean/sanitize - I'm skilled enough to cut a hole in the top (what will actually be the bottom of the keg), but how do you seal it once it's open? I've seen hand cut rubber gaskets and plastic plates with grommets and such. Another kicker - I like to ferment ON the grain as much as possible. So getting INTO the keg is important.

Is anyone else out there using a keg as a fermenter? I'd love to see what you've done. I'm even contemplating getting a friend to weld on a 8" ferrule and drill/tap a cover.

[The KYChemist]

I kinda like the idea, but I personally, wouldn't do it. Everything I know, about ferments, tells me solids settle to the bottom. If you are planning on feeding the boiler, straight from the bottom of the fermenter, how are you going to keep solids from getting transferred? Where they could possibly scorch an internal element, or the bottom of your boiler? Not being a smart-ass, just curious. I always rack and clear my washes, so there are no solids.

[raven_r_one]

Yeah - this is what I'm struggling with.

I was thinking I'd open the valve to drain it and drain the yeast and any solids into one bucket, then send the rest into the still.

I'm _sure_ it's not that easy so maybe it's just a matter of racking it over - carefully (I blew an element not too long ago by racking over too much yeast).

I've also seen the solids (grain/corn/etc) plug up a valve.

I think I'll still go this route, but I'll be racking over.

Anyother designs?

[SoMo]

Do one ferment find the line where the solids settle and put your drain above that height maybe, or put a false bottom in it.if you've got an extra keg rack from one to the other, spitballing ideas.

[raven_r_one]

Do one ferment find the line where the solids settle and put your drain above that height maybe, or put a false bottom in it.if you've got an extra keg rack from one to the other, spitballing ideas.

Yeah, I like that - if you look at conical fermenters, there's a drain at the bottom (for yeast) and a drain higher up (I'm guessing for the clear liquids).

I'm thinking I'd have four ways in:
- A big opening on the top (really the keg bottom) - maybe 6 - 8 inches so I can get in and clean/scrub it as well as transfer the grain in (I can go into detail why I do this step manually)
- A 1/2" opening toward the top - this is where I'd pump in the filtered contents
- A 1/2" valve above where things would settle out to
- A 1/2" valve on the bottom, using a standard triclamp - to drain the yeast/solids (mabye I can find a 1" valve?)

I've seen some designs about sealing a big hole cut in a keg - anyone ever weld up a big ferrule?

[bellybuster]

I've been toying with a similar idea for quite some time. The flange on the keg is a handy connection point for a sanitary butterfly valve. I personally would cut the bottom ( now the top ) right out and just use a piece of plexi to cover it. A false bottom and you can ferment on the grain and drain out into a clearing fermenter prior to your boiler. The keg would need legs to bring the valve to a suitable height.
The reason I never went ahead is cost. The cost of it all comes pretty close to just buying a proper conical.

[raven_r_one]

Yeah - the keg will be next to nothing for me so I just need to invest in the construction (I have a lot of the parts kicking around).

The butterfly valve - I was thinking about a slow/controlled drain of the yeast - won't the butterfly just dump it out?

I've seen several plans now similar to what you talk about (rubber gasket, lexan/plexi cover, blow off valve in the plastic).

Seems pretty straight forward - just need thick enough lexan. Also would be nice to have the bolts welded in so you just use butterfly nuts.

[SoMo]

When I worked in a water bottling plant and moving tons of coconut carbon we had an in between transfer tank that water went into first allowing the solids the carbon to settle to the bottom while the water/fluid passed on to the next vessel. Think 3 in a row the middle vessel collecting the solids.

[bellybuster]

I've seen several plans now similar to what you talk about (rubber gasket, lexan/plexi cover, blow off valve in the plastic).

Seems pretty straight forward - just need thick enough lexan. Also would be nice to have the bolts welded in so you just use butterfly nuts.

no i mean a simple piece of plexi lying over the hole. there is no need for an air tight fermenter, there is no benefit to it at all.
You will be surprised how yeast and lees will clog a valve. The wish of slowly releasing the yeast/lees will soon be realized as a pipe dream. That stuff clogs up pretty tight. A butterfly valve gives you a large bore to dump the lees quickly. An alternative is an attached container for the yeast to fall into , the valve remains open during fermentation.

[Stonemull]

Chopped the top off a keg today to use as a fermenter/boiler with a few ideas from a beer brewing site, he made a wooden jig that fitted in the keg outlet and held the grinder in place, seemed like a lot of work for one hole though.

its pretty easy to use the top rail as a guide for an angle grinder,I ended up doing a fairly fast lap with the grinder only about 1/4 of the way through to get a good score line, then a slower lap about 2/3 of the way through till the steel was blueing, went through in a one inch area then put a reciprocating saw in the hole and followed the groove.

tried a 4 inch grinder first with only about a 3 inch disc left on it thinking i could get closer to the wall but it turned out far easier to use a 7 inch grinder. cleaned up the edge with a file and its not bad.



now the top pice gets reused .. cut grooves all through it with the grinder, cap the centre and hopefully just drop it into the keg bottom to keep the majority of grain away from the bottom while heating.

thats the idea anyway ..

edit.. one hint on the site was to put a few litres of water in the keg to stop the sparks sticking to the bottom, thats still in there in the pic with grinder wheel sediment, its spotless and shiney under that crud.

[Brendan]

I use an SS keg as a fermentor. Looks similar to the pic above, but without that lip that brewers normally leave for the lid.

It's brilliant, and I use it for AG mashes and rum ferments where an airlock isn't needed. I insulate it when needed and have a lid/cover cut out of the insulation material to sit on top and keep any dust or whatever out.

Also with the bottom drain...As you've already mentioned, many brewers and distillers use conical fermenters and have both a bottom drain for the solids, and a drain above the solids to drain liquid...I just rack out of the opening in the top and it works well for me

[Stonemull]

how did you cut it closer to the edge ? oxy or plasma cutting i guess..

i was trying to minimise the lip as much as possible though i have no doubt it may come in handy at some point.

[raven_r_one]

Well - took some time to finish this out, but here it is.

Worked great. No more shifting around between 6 gal buckets.

ALSO picked up a 30 gal "wine fermenter" (looks like a food grade garbage can with locking lid).

So now I rack over from the 15 gal fermenter to the 30 and let it settle out.

Then rack from the 30 gal into my boiler (10 gal at a time - usually about 2 charges).

Thoughts?

[raven_r_one]

wonderful. glad all the images were rotated wrong....