Catering thermos/tea urn as a mash tun?

[Mateusz]

Hey,
I’m looking for a proper mash tun to upgrade my brewing system and after many ideas I think I’ll decide for insulated mash tun. Does anyone using something like this item:
https://www.expondo.co.uk/royal-cat...hermos-container-50-l-with-drain-tap-10011212

It looks like after couple upgrades(changing tap for ball valve, adding false bottom etc.) it’s perfect item for set and forget, but how it will keep temp if I add recirculation system?

Looking for opinions cheers

 

[ARNWD]

I see no problem at all.

When I first read the post title I was thinking of the 2 liter type, Thermos branded flasks. Believe me or not but these are indeed used as mini mash tuns both for yeast starters and for home brewing pilot brews.

If I was in your place I would have already placed an order.


ARNWD.

 

[MashBag]

I had one of these.
Tbh I did a couple of runs (it worked OK if pre heated THOROUGHLY ) BIAB

But TBH I cannot recommend it. As a set and forget yes probably.

If you have **any** thoughts of upgrading it, no. Buy the kit you want now. You cannot drill it, you cannot nip-up fittings, or weld, all because of the insulation. And the stainless is really thin.

To be honest a plastic cool box would be better...a sentiment echoed by many brewers the world over.

 

[YeastFace]

Used one in my HERMS system. Worked perfectly. I cut out a bottom drain to minimise dead space.

 

[Mateusz]

Used one in my HERMS system. Worked perfectly. I cut out a bottom drain to minimise dead space.

Was it hard to get through insulation at the bottom? If you’ll have spare time, could you make some photos how you sorted it out?
I was thinking to buy without tap and make bottom drain as well

 

[peterpiper]

If doing recirculation, you'll definitely need added heat, to maintain temperature.

On my AIO, with a foam jacket, glass lid and partially insulated pipe. I'd say it's using around 300 to 500W to maintain mash temperature.
It's thermostatic, and cycles the 1kW heater, on maybe a third of the time.

An external pump might loose a bit more heat, but that's maybe offset by better mash tun insulation.

Some form of in line heating would work best.
RIMS heater systems are expensive.

If you already have a separate water heater, and an immersion chiller coil. You could pump wort through the coil, with it immersed in heated water.


shows how to make an in line heater for aquariums.
Unfortunately, aquarium heaters, nearly all have max temp limit around 34C. If only threre was some way to get higher temperatures.

SS cartridge heaters, could be used instead, and are very cheap.
230V ones, only have short wire tails, so a good electrician would be needed, to make up an earthed junction housing.
A 500W one, could be wired via a manual cylinder stat (the tall slim style), that's clamped to some metal pipework after heater.

There's 36V 13.8A 500W cartridge heaters with 1m waterproof lead. On AliXpress around £11
Its lead would go to
eBay switched supply 36V 500W £30 Needs plug lead wiring.

OR variable bench supply, 30V 10A. No mains wiring work, and you could vary the heat input. But you'd only get max power of around 350W, from the 36V 500W heater.

With a fixed supply, you'd have turn it on/off, for the heat required. Or add cylinder stat (on mains side of the supply).

 

[Mateusz]

If doing recirculation, you'll definitely need added heat, to maintain temperature.

On my AIO, with a foam jacket, glass lid and partially insulated pipe. I'd say it's using around 300 to 500W to maintain mash temperature.
It's thermostatic, and cycles the 1kW heater, on maybe a third of the time.

An external pump might loose a bit more heat, but that's maybe offset by better mash tun insulation.

Some form of in line heating would work best.
RIMS heater systems are expensive.

If you already have a separate water heater, and an immersion chiller coil. You could pump wort through the coil, with it immersed in heated water.


shows how to make an in line heater for aquariums.
Unfortunately, aquarium heaters, nearly all have max temp limit around 34C. If only threre was some way to get higher temperatures.

SS cartridge heaters, could be used instead, and are very cheap.
230V ones, only have short wire tails, so a good electrician would be needed, to make up an earthed junction housing.
A 500W one, could be wired via a manual cylinder stat (the tall slim style), that's clamped to some metal pipework after heater.

There's 36V 13.8A 500W cartridge heaters with 1m waterproof lead. On AliXpress around £11
Its lead would go to
eBay switched supply 36V 500W £30 Needs plug lead wiring.

OR variable bench supply, 30V 10A. No mains wiring work, and you could vary the heat input. But you'd only get max power of around 350W, from the 36V 500W heater.

With a fixed supply, you'd have turn it on/off, for the heat required. Or add cylinder stat (on mains side of the supply).

Thanks for long post mate, appreciate.
I thought the same that recirculating wort will lower the temp significantly, however for now I would just sit the mash without recirculating I think, I can add some Rims tube with proper heater later on.

 

[Wynne]

I used a 35l version with a false bottom as a mash tun with a 30l Burco Cygnet as the kettle. As@MashBag said it is important to pre-heat it as it has quite a thernal mass. I circulated the strike water through the Cygnet controlled by an Inkbird to achieve/maintain the desired temperature. Worked fine but I’ve since switched to a G40 as better sized for my 38l fermenters.

 

[Mateusz]

I used a 35l version with a false bottom as a mash tun with a 30l Burco Cygnet as the kettle. As@MashBag said it is important to pre-heat it as it has quite a thernal mass. I circulated the strike water through the Cygnet controlled by an Inkbird to achieve/maintain the desired temperature. Worked fine but I’ve since switched to a G40 as better sized for my 38l fermenters.

How did you control flow? Just by ball valves?

 

[YeastFace]

Was it hard to get through insulation at the bottom? If you’ll have spare time, could you make some photos how you sorted it out?
I was thinking to buy without tap and make bottom drain as well

Not massively, I used a holesaw for the outer skin of stainless and insulation, and a qmax cutter for the inner.

The bottom drain (a deck fitting) was offset and not central like the Brewbuilder ones, so I only needed a short barrel nipple to connect the bottom drain to the tap.

I sold that setup a couple of years ago and don't have any photos of the inside of the mash tun I'm afraid.

 

[Wynne]

How did you control flow? Just by ball valves?

Yes, and by switching pump on and off manually.

 

[Mateusz]

Not massively, I used a holesaw for the outer skin of stainless and insulation, and a qmax cutter for the inner.

The bottom drain (a deck fitting) was offset and not central like the Brewbuilder ones, so I only needed a short barrel nipple to connect the bottom drain to the tap.

I sold that setup a couple of years ago and don't have any photos of the inside of the mash tun I'm afraid.

Right nae worries pal, cheers