Coolbox mash tun build; tips?

[Francois]

After brewing BIAB style in my electrim bin since I started all grain eight months ago, I'm finally going to go the whole hog and make myself a separate mash tun! Seems there's better efficiency up for grabs with one, and I'm liking the idea of being able to get another mash on while there's a boil going (two beers in one brewday would be a winner considering my limited time for brewing...)

Get the impression several of you have made your own, so I'm just after any little pointers anyone may have really... any ways I can make the build itself easier? Any particular materials/processes for added insulation that'll make for a more efficient mash?

And lastly, can I skip the whole false bottom/manifold part if I line the tun with my swathe of BIAB nylon? Might just be being a bit dense here, but I imagine it would do the trick (and avoid stuck mashes) (and make cleanup a lot quicker rather than having to dig the spent grain out...)

Any guidance/benefits of greater knowledge are as always welcomed with gratitude!

[NobbyIPA]

i have a thermos cooler box with fittings all stainless from bes

6962 12 m x 12 mm, P.T.F.E. TAPE 1 £0.17 £0.17
14321 1/2" x 3/8" BSP F, REDUCING SOCKET, 316 S/S 1 £1.57 £1.57
14461 3/8" BSP PM, NIPPLE, S/S 1 £2.30 £2.30
14557 3/8" BSP TM, HOSE TAIL ADAPTOR, S/S 2 £1.64 £3.28
20176 3/4" Multi-use Washers 3 £0.26 £0.78
20306 2 peice 3/8" 1 £7.58 £7.58




had this type of grain filter earlier but it had problems where it would get squashed with+6kilo of grain in there

upgraded to 22mm slotted copper never let me down even with wheat


and fly sparge at a rate of no more than 1 litre liquor in i litre out per minute
https://www.youtube.com/watch?v=-HLFxcLF7N4

using a drilled out washing up bowl

[Francois]

Awesome, cheers nobby! By the look of that collection of fittings my screwfix order might be a bit... lacking lol. Forgot about the nipples for tubing connect, but sure I can pick up some extra bits once the main build's done.

Do you find fly sparging as opposed to batch has much of an effect on efficiency when it comes to hitting OG?

[NobbyIPA]

IMO fly is the way
i get lovely beer this way so i stick to it

never tried batch so cannot comment

it seems to be a personal choice thing

[Fil]

Since initial attempts at fly sparging and making a meal of it ive batch sparged since, keep thinking i may fly again but haven't yet, perhaps next brew ??


the net bag idea, could be a real pita when doughing in unless well fitted and secured tightly over the edge, Underletting or filling thru the drain with the dry grain in place could help,
Also the risk of concentrating the drain thru the small circle of net covering your drain hole. but a rough cut FB or even some clean spare copper tubeon the base could help create a good even drain.

kitchen chopping boards are cheap foodsafe and easily worked false bottom candidates

[Francois]

Chopping boards eh? Makes sense... this brewing lark's really cutting into my kitchen equipment now though, the electrim bin's false bottom is a pizza tray as it is

Thought about getting a cheap baking tray from wilkos and drilling a load of holes in it false bottom wise, would probably fit a standard size coolbox pretty well without adjustment... four bolts in it to keep it raised into position. I'm starting to think I'm into this as much for the Heath Robinson/McGuyver element as I am in it for the beer

[Fil]

another tip its much easier to make a drain seal with a drilled thru tank connector on the inner skin alone, while some have sealed a 2 wall job its much more problomatic unless the skins are parallel And the insulation employed is packed evenly And will withstand some pressure to create a seal without colapsing, if your concerned about the valve anchor being weak you can repack the larger hole in the outer skin and void externally with builders foam or decorators caulk supporting the hardware.

a drilled thru 15mm brass compression tank connector will allow u to seal15mm tube pushed thru the fitting as u have removed the stop giving u a tube end for further connections both inside and outside the tun.

[Rick_UK]

My tips are as follows based purely on my trail and error experience! :
- Check the insulation is decent, if not replace with cut up camping mats
- Insulate the lid thoroughly if it is not already
- Go for one slighty bigger than you think you need
- put some solid packing around the outlet hole between the 2 skins to improve the seal on the connector - I just used a few scraps of wood
- Use a threaded nipple rather than a tank connector with plenty of ptfe tape so you can easily attach a ball valve and filter
- Grain bag works fine and less chance of a stuck mash
- I had less trouble with a simple steel braid filter and could batch or fly sparge without issue, a false bottom would not work well for batch sparging

Rick