Insulating brew pots

[greenwood]

As my previous post I was considering buying two 50l thermos pots . However, I realise I have two unneeded 50l brew pots with taps and bazookas . Just need to insulate them. I’m sure blankets and old coats would be enough .. I’m sure I’ve tried it years ago. Any ideas ?


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[vacant]

Some people use foam sleeping mats for camping.

Before I got a thermopot I used a cylinder jacket - easy to wipe clean and dry at the end of the day.

[TheSumOfAllBeers]

You can also get sheets of thermawrap relatively cheaply and insulate the vessel that way. The more the merrier and it’s cheap.

If you want to get more serious there is armaflex foam insulation which is the mutts nutts but pricey. Probably cheaper than the difference between a regular pot and an insulated one. You will probably want to protect the armaflex though as it can damage easily and absorb spills. The previously mentioned thermawrap fits the bill I think.

[Marshbrewer]

This is on my to do list. What do people use to keep the thermawrap held to the brew kettle?

[Haydnexport]

duct tape

[Kev888]

There are many options of course, so there will now be a slightly tedious list. But FWIW these are my thoughts on those I've tried over the years:

• An outer shell around the pot, with the void filled with expanding foam - or ideally the two-part fast setting equivalent - works very well indeed. It is a close DIY cousin to thermopots and so quite hard to beat, but takes a bit of work to DIY well. I've used both plastic containers and wooden cases as outers; If you want a posh stainless outer shell, then possibly no particular £saving over a thermopot (though it does give you the option of thicker/better inner pot than is standard with those).

• Closed-cell flexible foam sheeting (such as armaflex or some types of neoprene) is very effective and easy to use, though expensive. Camping mats and similar are much cheaper but vary greatly as to their material and cell structure (and so their insulative qualities) so mileage varies enormously.

• It is possible to put multiple creases in 25mm PIR board (celotex, kingspan etc) and so form it to a cylinder without breaking it, with care. About as effective as the two-part expanding foam and doesn't need an outer shell to contain it - though it isn't massively robust without one.

• The thin foil-faced mats (bubble-wraps and similar) do help and are also good for making wipe-down outer layers to other insulation. But in themselves, to get their full/touted insulation value, they need to be installed with a big gap between themselves and the pot which isn't usually very practical. Some have a coating over the alu foil (or use something else shiny), but some just have bare aluminium foil, which corrodes and is quite susceptible to acidic stuff like wort and starsan.

• Fibreglass and rockwool etc can be very effective but they need to be very thick to match the closed-cell foam/board equivalents in terms of insulation. If they're squashed down (e.g. with wrapping) then this reduces their effectiveness. Some sort of outer layer is needed to contain the fibres and make cleanup possible, preferably one which won't puncture or tear easily when handling

• The classic one is timber slats. Quite nice looking and at least vaguely reasonable in performance. But they'd have to be quite thick and have all the voids filled to be especially good insulators, so at homebrew scales perhaps best for heat retention (and safety protection) around boilers rather than mash tuns.

I've not seen the other thread, but in terms of context:
For a boiler you want something that won't melt or go brittle with heat. But most things would improve the heat loss over a single-skinned pot - many times over with ease; even one layer of the foil stuff or thin wooden slats for example would make a big improvement. (If you use a gas burner then the options are more limited; heat shrouds and ceramics and the like).

For mash tuns, if it is a recirculating (RIMS/HERMS etc) then the demands on insulation aren't that great either; some insulation is good but it need not be huge. But for passive heat retention of mash tuns (my own preference), then IMO you can't easily beat properly thick layers of closed cell foam - be it flexible, two-part moulded or bent PIR.

Cheers

[greenwood]

Thanks for all the advice . What do you think ?


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[Kev888]

The only way to know is to test, really. It could be sufficient, but if there is no other insulation below the bubble-wrap you may possibly find the heat loss greater than wished. Though they'll certainly be much better than the bare pot alone.

[bigrichlock]

Armaflex from ebay, the 18mm sheet stuff is fantastic stuff

rich

[greenwood]

I reckon if I chuck a big fat blanket over top they should hold temp for 90 mins ... especially if I start a bit warmer .any way planing a test brew . Will update !


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[greenwood]

The results are in ! Started at 67 degrees because I thought it would drop a few .Put thermowrap on top of grist and a sheet over lid and under tun . Big thick blanket over the lot 95 minute mash 67 degrees at end ! I reckon the beer will be on the sweeter side so I’ll do a forward hopped IPA . At least I know it retains the heat well .... might not need blanket ??


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[HTH1975]

I only lost 0.5C in my mash today using two blankets around an uninsulated boil kettle. Most I’ve lost is 5C with no insulation.