60l Ali Pot Cut Up To Make New Tun.

[Yeastie Beastie]

Good Morning All,

I sacrificed my mash tun last week to be an electric HLT and considered using my unused big 'ol plastic fermentor as new tun, it all looked feasable, it never really got used as I prefer doing 2 x 23L batches rather than a double. Gives me a chance to have 2 beers and learn twice as much, try twice as many new things yada yada.
But as it usually goes, once you cut it, you will want it tomorrow.

Some time back I bought a spiral burner and a 50L pot, it was more cost effective to go for the 60L for transport costs so I did.
The 60L ended up being just too big and clumsy for my liking so I got another 50L and pushed the 60L aside for something in the future. Yesterday was that future.

I basically thought that a 60L ali pot cut in half would make 30L - plenty big enough for a tun. Also as I am currently designing my 3 tier gravity brew stand the lower the tun, the lower the overall height of the completed rig. Very import to me.

Before I thought twice and changed my mind about chopping a good pot the cutting disc was on the angle grinder and the first cut was under way - too late to turn back now.

File off a bevelled edge so no blood would be shed next brew day, a run around with some wet and dry sandpaper, drill a hole for the tap, knead up some knead it to seal the tap ( like I did here in the second set of pictures ), add my falsie, drill another hole for my BB return Dish and job done. All I need now is to order a dial thermometer, get some bolts tomorrow for the handles and ill be done. Might not use handles yet as I might incorporate a tipper on the new rig.

Last night I gave it a dry/wet run with just water to see if insulation was neccesary. My last tun was the 50L ali pot and would only lose 3 degrees over 1 hour so it wasn't insulated but this pot, same brand, has a thinner wall so insulation may be required.

10:35pm - Pre warmed with hot tap water - I do this religiously.
10:40pm - Added 20L water @ 70 degrees.
11:00pm - 70 degrees still.
11:20pm - 68 degrees
11:40pm - 66 degrees

4 degrees lost over an hour - not too bad but I think insulation with some airflex will be the go.

 

[sav]

A 60lt tun would have been a great size,good work its nice and neat
sav

 

[NickB]

+1

You're really limiting yourself by cutting down on size. A 60L would have been fine for single batches, and given you room to expand down the track. Personally, would have used it as is, or sold it and bought a smaller pot!

Does look nice and neat though.

Cheers

 

[T.D.]

Ali's a pretty good conductor. Having excess headspace and surface area when doing small mashes would not have been the best thing for temp stability. So I can understand wanting to cut it down.

The geometry of the MLT isn't that great now if you fly sparge... Not the end of the world but tall and thin is usually considered to be a better shape.

Also if your kettle is a smaller diameter than the MLT that ring you cut off the top would make a great wind protector around the burner.

 

[Thirsty Boy]

Good point - it should be OK with a decent diameter false bottom in there, but you would want to make sure you kept a layer of liquid over the top of the mash and drain nice and slow.. otherwise you might just suck it down the middle and miss all the goodness at the edges.

The geometry is now much more like a "lauter" tun ... its perfectly OK for continuous sparging, but you need to be careful about technique.

 

[Yeastie Beastie]

Also if your kettle is a smaller diameter than the MLT that ring you cut off the top would make a great wind protector around the burner.

Great wind protector, my first thoughts. Pity I have just converted to electric lol

Good point - it should be OK with a decent diameter false bottom in there, but you would want to make sure you kept a layer of liquid over the top of the mash and drain nice and slow.. otherwise you might just suck it down the middle and miss all the goodness at the edges.

The geometry is now much more like a "lauter" tun ... its perfectly OK for continuous sparging, but you need to be careful about technique.

Great tip, thanks. Definately something I didn't think about.

T.D - The excess headspace would have been pretty large, another reason for the cut down.

I really didn't like the size of the pot to start with, just too big & clumsy and ill never probably do double batches so there was never going to be a need for it down the track. Also being in the country selling was an option but postage was the killer there.
Also I wanted something low profile as I am in the process of designing a gravity fed brew rig stand and the lower profile means a lower overall height. But in saying that and mentioning continuous sparging maybe a single tier with a march is going to be the go.

Also, on cutting it down I noticed a huge difference in the wall thickness of the top of the pot and the centre of the pot. I am assuming when they are spun the top is thicker to increase rigidity. The top of the pot was 4mm and reduced down to 1.5mm
in the centre. Something I never noticed before. Also worth the mention that this was not a cheap junk shop pot either.

 

[T.D.]

That is very interesting re the wall thickness. You may have discovered a bit of a crafty ploy used by these pot producers. They are claimed to be 4mm thickness (which you'd assume meant throughout the whole pot) but looks like they may keep it 4mm at the top where you can easily see the thicknss but then whittle it away a bit in the centre! Interesting!

Shouldn't cause any issues though, the main thing with these things is to have some good thickness in the base, especially if using direct heat.

I reckon it will work well. And as you say, if building a 3 tier system short squat vessels are a big bonus. As long as you get the sparge right as TB said.

 

[Yeastie Beastie]

Batch sparge or fly sparge or any other methods I don't know about?
Which would be recommended?

 

[Thirsty Boy]

Either will be fine - batch will be pretty quick in that pot. If you do fly, just be mindful of your technique. There is nothing wrong with that pot for fly sparging, its just that shortcuts and hurrying are more likely to bite you in the arse than they would be in a taller narrower pot (mind you, they have their own issues)

Try a few brews of either and see which you like better. Then after you've been going for a year on your system.. try flip flopping again for half a dozen brews and see if the extra experience under your belt has made you change your mind.