Holes in mash tun

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Pikey
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Holes in mash tun

Post by Pikey »

In prep for AG, I got a mash tun.

Stainless boiler, electric heated pot, with inner pot which fits fairly snug inside it, with a flange, resting on a lip in the outer. the inner probably hold about 80 Litres and has holes around teh top thus ;
inner resize.jpg
inner resize 2.jpg
It's fairly obvious how the thing works, all except all those holes around the top of the inner.

Water goes in the outer, which can be used on its own if desired. grain and water goes in the inner and switch on. Water in outer heats up and transfers heat through to inner like a "Bain marie". Mash can be heated and held at any temp required by temperature sensor STC 100 type and power controller (my addition). So what are the holes for ? just to equalise the pressure between the 2 vessels, or is there another purpose ? :?

[Edit - please excuse grubby fingers - messing about with prop shaft couplings - but camera needed something to focus on :roll: ]
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Re: Holes in mash tun

Post by Pikey »

No ?

I couldn't either - Anybody agree with me that they're for pressure equalisation ?
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Brutal
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Re: Holes in mash tun

Post by Brutal »

I would guess so if the jacket boils over, it would just flow into the inner pot? through those holes? Maybe to let steam out from the jacket in a safe direction? How tight do they fit together?
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Pikey
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Re: Holes in mash tun

Post by Pikey »

Thanks for your reply - there is a line on the outer, which I think is a "water level" line. It is low enough for the water not to boil over I think - but there's nothing to stop you putting more water in of course.

It's a "snug fit". I lifted the inner out and when you put it back and "let go", the air underneath has a damping effect and the inner goes down gently with a "pfffft" noise. I don't think it is tight enough to prevent steam escaping, but it may have to lift the inner to do so. Full of wort, that inner would take Some lifting ! When full, it might be a tight enough seal so that the inner might have to be lifted and the steam would have to produce quite a pressure to do that.

Those holes would overcome any of those possibilities I expect.

I just wondered if anyone knew of any other explanation as there are a lot of them and sometimes when I've bought stuff, several years later someone has said "oh I see it has a xxxxx valve on it - for when you want to do so and so"

I just suspected this might be one of those cases and they might just be something to do with an intended steam injection or something.
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Re: Holes in mash tun

Post by yakattack »

Hay pikey. Missed this one till now.

I'm going to say yes that it is to vent steam into the pot. Keeps the heat in the system I would think.

Would need more pics of the setup to be sure though
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Re: Holes in mash tun

Post by still_stirrin »

Brutal wrote:....Maybe to let steam out from the jacket in a safe direction?..
I think this too.

If there is a threaded inlet low in the jacket, it is probably for steam input. Also, is there a small threaded (drain) outlet in the bottom? That would be for the condensate.

Atmospheric steam in the jacket vents through the band of holes at the top, into the vessel and out through the lid. The holes ensure a vapor path keeping the steam from over pressurizing the steam generator and piping. The holes also provide vacuum relief for when the steam source is shut down.

Also, the holes allow you to remove the inner vessel to clean up the lot by reducing the potential for distortion from positive or negative pressurization.

I'd say you could use the jacket for steam (more effectively than hot water) for greater BTU (kW for you metrics) transfer. Regulate the steam flow (lb/hour) to control your mash boil rate.
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Re: Holes in mash tun

Post by seamusm53 »

[quote=

I couldn't either - Anybody agree with me that they're for pressure equalization ?[/quote]

Yes. And to allow for circulation of liquid from heated environ (immediately above heat source) to overall boiler volume.
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Re: Holes in mash tun

Post by Pikey »

SS - There is a drain, in the bottom of the outer, at the bottom of the sump containing the heater element. The sump is about 7" (165mm Deep ) :
element resize.jpg
The drain is attached to a half inch copper and has a half inch valve to operate at a lower level than the tank bottom.

There is no other perforation, so no "steam" inlet as such


There is a cover which covers the sump, but would struggle on its own to hold back anything but the coarsest grain imo.
filter bott resize.jpg
However, clearly it has the capacity to be used without the inner pot if desired.

I'm not sure what capaciy the element is - but I expect it is around 2 - 2.5 kw. any more than about 10-12 amp would need special wiring over here and it has a 13 amp plug on it.

There is a thermostatic control incorported which is adjustable and seems to go from 30 - 110 C - Presumably this just allows the temperature of the heating water to be controlled and how long that would take to bring a wort up to temperature is anyone's guess.
temp resze.jpg
I'm thinking that overall, this might be a nice useful piece of kit !

[Edit - using a low volume of water and turnng the thermostat UP woud enable it to generate steam, but whether that would be useable as a "steam boiler", seems doubtful to me as the lid is not a sealed fit among any other reasons.

I suppose that could be engineered and a "Pressure cooker" type arrangement bodged up - but Jeez - some pressure cooker ! :shock: ]
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