Possible mash tun?

The forum for discussing all kinds of brewing paraphernalia.
Post Reply

Possible mash tun?

Post by DaddyLouLou » Tue Oct 13, 2015 5:50 pm

Has anyone tried to make a mash tun from a polystyrene "fish box", like this http://www.ebay.co.uk/itm/54-LTR-POLYST ... 419cf31dd8

It's a lot cheaper than a cool box, and I believe they're 1" of polystyrene, so it should hold temperature OK. Also, it should be easy to cut a hole for the plumbing, but:
Is it food safe (I guess so, as it can be used to transport fish)?
Can it handle temperatures as high as ~80°C?
Will I be able to get a good seal around any holes cut?

Any other thoughts?

Steady Drinker
Posts: 92
Joined: Thu Apr 12, 2012 5:32 pm

Re: Possible mash tun?

Post by irv » Tue Oct 13, 2015 7:50 pm

you can get cheap cool boxes for <£10
doing anything with polystyrene would be very temporary as it will fall apart.
you wont be able to put any pressure on the walls to make a seal
cutting a nice hole will be difficult
there is probably about £2 worth of polystyrene there .

i could probably go on with other thoughts

Under the Table
Posts: 1154
Joined: Sat Jun 23, 2012 10:13 pm

Re: Possible mash tun?

Post by chris2012 » Tue Oct 13, 2015 7:56 pm

I definitely wouldn't bother, polystyrene is so flimsy, it will just fall apart.

lord groan
Lost in an Alcoholic Haze
Posts: 506
Joined: Sun Aug 12, 2012 12:34 pm
Location: Hampshire

Re: Possible mash tun?

Post by lord groan » Tue Oct 13, 2015 8:47 pm

Agree with the others, the expanded foam will be impossible to clean, and it'll crumble quickly, not to mention I'm not sure how food safe it really is.
That said these are exactly what I used for the insulation on my first mash tun. I got a mango chutney barrel free from my local restaurant by asking for it at the kitchen door, then I asked at my local chinese supermarket when I spotted a delivery of these big white polystyrene boxes, they just throw away these boxes after emptying them! With a modest amount of cutting I made a full enclosure for the mango barrel then backfilled the gaps in the corners with builders expanding foam after wrapping the barrel in plastic sheet so I could be certain of removing it from the foam enclosure easily.
As you can see it's really easy to spray too much foam down the gaps!
I ended up with 2 halves enclosing the bottom 3/4's of the barrel and a 3rd box cut down to act as a lid, all foam filled and trimmed off surplus. In use it lost around 1 degree over a 90 minute mash as long as I preheated it.

User avatar
Falling off the Barstool
Posts: 3443
Joined: Sat Mar 17, 2012 4:09 pm
Location: Rye, East Sussex

Re: Possible mash tun?

Post by Pinto » Wed Oct 14, 2015 12:02 am

As others have said, it wont make a tun itself - but could work well as insulation for one....

Use it to insulate something like one of the PP "storage boxes" you can buy -this kind of thing
Primary 1: Nonthing
Primary 2 : Nothing
Primary 3 : None
Secondary 1 : Empty
Secondary 1 : None
DJ(1) : Nowt
DJ(2) : N'otin....
In the Keg : Nada
Conditioning : Nowt
In the bottle : Cinnamonator TC, Apple Boost Cider, Apple & Strawberry Cider
Planning : AG #5 - Galaxy Pale (re-brew) / #6 - Alco-Brau (Special Brew Clone) / #7 Something belgian...
Projects : Mini-brew (12l brew length kit) nearly ready :D

Join the BrewChat - open minds and adults only ;) - Click here

Drunk as a Skunk
Posts: 950
Joined: Fri Feb 10, 2012 12:09 am
Location: West Somerset

Re: Possible mash tun?

Post by JamesF » Wed Oct 14, 2015 12:26 am

I'm not convinced it would make a good mash tun by itself and I'd be concerned about its food safety at mash temperatures. I see no reason why it shouldn't be robust though. I have a number of polystyrene beehives and they're pretty tough. You certainly wouldn't want to get smacked around the head with one.


Even further under the Table
Posts: 2999
Joined: Wed May 09, 2012 6:42 pm
Location: Warrington England usually drunk or being mithered by my 2yr old or wife

Re: Possible mash tun?

Post by sbond10 » Wed Oct 14, 2015 8:07 am

I think as an outer to a cheaper cool box tun it would be ok but not as a tun it's self

Post Reply