False bottom

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Bigbud78
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False bottom

Post by Bigbud78 » Sat Jan 20, 2018 10:40 pm

Just finished my thermopot conversion no now thinking about false bottom, I usually mash in a bag so not sure If I should go for anything expensive or not. The brew builder one looks great and I did think about trying to make my own but wondered if they scratch the mash tun ?

I assume if I didnt use a false bottom its not going to drain great even though Im using a bag, any thoughts or ideas ?

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vacant
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Re: False bottom

Post by vacant » Sun Jan 21, 2018 12:03 pm

What size thermopot? My 33 ltr uses a £3 Ikea stainless splatter guard edged with split thick silicone hose. It is bottom draining meaning a small metal rod can be slotted in the drain plug supporting the middle of the splatter guard to keep it off the bottom of the tun.
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Kev888
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Re: False bottom

Post by Kev888 » Tue Jan 23, 2018 8:06 pm

If you are no-sparge or full-volume mashing then lifting the bag off the bottom will allow it to drain without a false bottom. Or it is possible to do an infusion rinse after the mash by putting clean liquor in the (previously drained) mash tun and dunking the grain bag in again.

A false bottom will allow proper fly-sparging or continuous-sparging. It will also allow batch sparging without lifting the grain in and out, and without the floppy bag to interfere with stirring. It isn't very common to use a bag 'as well' as a false bottom, so I can't really say from experience how that would work. TBH I'm not sure why both would be wanted, unless you were thinking of more of an open grill or something to support the bag rather than a proper false bottom?

As Vacant says, some split silicone tube, or split beer line, or purpose-made edging, can both help prevent scratching the mash tun sides and permit a tight enough fit to stop grains getting past. My own preference for false bottoms (in the absence of anything frighteningly expensive) is perforated stainless sheet of 2mm holes, usually with legs to help support it. But mine tend to be reasonably large so I've not tried mesh or splatter guards.
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Re: False bottom

Post by Fil » Tue Jan 23, 2018 9:07 pm

well my single test of mashing in a bag without a FB in the tun drained fine.. (batch sparging) but the bag did curtail my doughing in and mixing due to caution and a desire not to snag/catch/tear the bag.

a cut to size perforated SS plate can be stood off by screws/bolts, but sized to fit the perforations without any widening you will need quite a few to avoid damaging the thin base skin even if the bolt/screw bottoms are 'protected with dome ended nuts.

in my 80l tun i use a cut perforarted SS plate and a length of silicone hose, the hose sits snugly around the pot perimeter and the ss plate sits above that. im sure the grain mass (upto 15kg so far..) bottoms out the centre of the FB, but it drains just fine, and the mass seals the fb against the silicone tube upon which it sits..
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Bigbud78
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Re: False bottom

Post by Bigbud78 » Wed Jan 24, 2018 2:28 pm

Ive ordered 1mm thick perf plate with 2mm holes, 20 m6 bolts with dome head nuts. Planning on 17 contact points so hopefully that's enough, cost £40 all in so the brewbuilder one is actually a good price. If I hadnt had ordered the bolts already id have prob just ordered from him when I saw the price fo the plate lol

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Kev888
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Re: False bottom

Post by Kev888 » Wed Jan 24, 2018 8:17 pm

Yeah, perforated stainless isn't cheap, though it works pretty well and so IMO no bad investment. The false bottom (or equivalent) really is the key to a decent mash tun - especially if you ever want to fly sparge. It has always seemed fairly good value compared to drilling your own or getting a custom slotted or wedge-wire false bottom made.

The 1mm thick, 2mm diameter hole stuff is what I use too, IIRC the last one cost me about £30 for a 500x500mm bit. It is thick enough, with support legs for bigger areas.

Though if for some reason you have a high-head/suction pump direct on the outlet, take a little care. Should things stick too badly then with a wide area, high suction can really build up to a massive total load, whatever type of bottom you use.
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Bigbud78
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Re: False bottom

Post by Bigbud78 » Thu Jan 25, 2018 11:17 am

Kev888 wrote:
Wed Jan 24, 2018 8:17 pm
Yeah, perforated stainless isn't cheap, though it works pretty well and so IMO no bad investment. The false bottom (or equivalent) really is the key to a decent mash tun - especially if you ever want to fly sparge. It has always seemed fairly good value compared to drilling your own or getting a custom slotted or wedge-wire false bottom made.

The 1mm thick, 2mm diameter hole stuff is what I use too, IIRC the last one cost me about £30 for a 500x500mm bit. It is thick enough, with support legs for bigger areas.

Though if for some reason you have a high-head/suction pump direct on the outlet, take a little care. Should things stick too badly then with a wide area, high suction can really build up to a massive total load, whatever type of bottom you use.
Cheers, yeah got a decent pump but I'll still be batch sparging for speed with a bit of recirc. Its new kit so will take some getting used too :D

Bigbud78
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Posts: 96
Joined: Fri Nov 25, 2016 2:32 pm
Location: Manchester

Re: False bottom

Post by Bigbud78 » Thu Jan 25, 2018 11:17 am

Kev888 wrote:
Wed Jan 24, 2018 8:17 pm
Yeah, perforated stainless isn't cheap, though it works pretty well and so IMO no bad investment. The false bottom (or equivalent) really is the key to a decent mash tun - especially if you ever want to fly sparge. It has always seemed fairly good value compared to drilling your own or getting a custom slotted or wedge-wire false bottom made.

The 1mm thick, 2mm diameter hole stuff is what I use too, IIRC the last one cost me about £30 for a 500x500mm bit. It is thick enough, with support legs for bigger areas.

Though if for some reason you have a high-head/suction pump direct on the outlet, take a little care. Should things stick too badly then with a wide area, high suction can really build up to a massive total load, whatever type of bottom you use.
Cheers, yeah got a decent pump but I'll still be batch sparging for speed with a bit of recirc. Its new kit so will take some getting used too :D

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