eBIAB Dual Purpose HERMS/Chiller Build Thread

[beerlover1983]

sand i must say what a great idea

[Fil]

Regarding the pressure cooker running cold and not sealing, have you come across the 'everlasting gasket/washer'? the idea is you can make a foodsafe washer any size/shape using a template and a few rolls of ptfe tape (depending on size, bigger = more ptfe...)
simply wind the ptfe tape round and round the template, if in the case of 1/2" bsp or similar where the roll is too big to pass thru the centre roll flat tape onto a drinking straw as a bobbin and cut the surplus straw away with scissors (easy with a burger king straw as that will slip over a drill driver screw bit.. hehe)

when heated ptfe contracts a bit so your tightly wound everlasting gaskets top layer of tape will seal in all the underlayers and the card giving you a custom soft ptfe gasket for a budget price, ptfe is 30-50p a roll

so perhaps with a few rolls of ptfe and an old cereal box you could knock up a few extra sealing washers to seal the pressure cooker when cooling??

[ajclarkson]

sand i must say what a great idea

I've just updated the picture post to clarify that the sand was baked to dry it, and I used fine sand and sieved it to filter out the larger bits. But yeah, so happy with the results, worked better than I could have imagined.

Regarding the pressure cooker running cold and not sealing, have you come across the 'everlasting gasket/washer'? the idea is you can make a foodsafe washer any size/shape using a template and a few rolls of ptfe tape (depending on size, bigger = more ptfe...)
simply wind the ptfe tape round and round the template, if in the case of 1/2" bsp or similar where the roll is too big to pass thru the centre roll flat tape onto a drinking straw as a bobbin and cut the surplus straw away with scissors (easy with a burger king straw as that will slip over a drill driver screw bit.. hehe)

when heated ptfe contracts a bit so your tightly wound everlasting gaskets top layer of tape will seal in all the underlayers and the card giving you a custom soft ptfe gasket for a budget price, ptfe is 30-50p a roll

so perhaps with a few rolls of ptfe and an old cereal box you could knock up a few extra sealing washers to seal the pressure cooker when cooling??

Great idea there Fil. My Dad has actually just got his hands on some gasket material from his work thanks to a kind engineer being slipped a bottle of Vanilla Porter

So I'm hoping that will hold the seal, but if it doesn't I will be sure to give your ptfe method a go. Cheers!

[ajclarkson]

Yesterday saw a few tests of the new gasket in the pressure cooker, and the results weren't perfect but were encouraging.

The electric pressure cooker consists of an outer cast iron pot, with heating element, and then an inner aluminium pot where the food should go, which sits on top of the element and forms a seal with the lid. When replacing the original seal of the pressure cooker with the gasket material there is too much of a gap between the lid and the inner pot to create a seal. I'd already seen this issue with the existing seal and so had made up a couple of aluminium shims to sit on top of the element and squash the inner pot into the lid while allowing heat conductivity still. Needed a couple more to close the new gap.

The pressure cooker leaks if you hit it with full mains water pressure, but will hold at about half as things stand. As I'd run out of Aluminum to make more shims, decided to just hold the flow at that and test it, it brought boiling water down to 22C within 25 minutes, so I'm pretty happy about that. I've got some more aluminium today so will be making a couple more shims to really push the inner pot and lid onto the new gasket and I think it will hold more pressure. Might not hold full mains pressure, but with the encouraging results of the first test, it might not have to

[ajclarkson]

With the new shim in place, definitely a better seal and much higher water pressure. Tested under the same conditions as yesterday, and reached 20C in pretty much half the time. I'm happy enough to go ahead with that, and so I'll be placing a restrictor on the water inlet of the pressure cooker to allow me to just turn the water on full and be sure of it not leaking.

[ajclarkson]

All of the pieces are finally coming together now, just put together the valve pump assembly to mount on the brew pot. In the interest of portability / flexibility / storage ability I had planned on two 3 way valves mounted directly onto the pot:

Boiler -> Drain or Pump
and
HEX Return -> Boiler or Fermenter (can also be used to fill the boiler from a hose)

The stainless 3 way valves are really quite heavy (and not at all overkill ) so I decided to use T's rather than elbows coming out of the boiler, and link the "dead" arms with a piece of bar to spread the weight and stop them from twisting the pot. Thankfully a kind engineer turned me a really nice piece of stainless bar with a 1/2" thread on each end for this purpose:



Very happy with the outcome. Just need to drill the pot and get it fixed onto the bulkheads at the weekend. Also have an order in for a Mr Lard sight glass, and managed to acquire a fermenting fridge to replace my old water baths, so the STC will be getting installed this weekend too. Almost brew time!

[ajclarkson]

Progress has kicked on a bit with this now, and it's almost there.

The valve assembly is now mounted to the brewpot and isn't leaking which is always a bonus! Adding the strengthening bar really helped it feels solid as anything now, and provides a handy handle for tipping the pot up for cleaning and such!



Top to bottom the 4 hose connections are:

1 - Fill kettle from mains water / Out to Fermenter on return from chiller
2 - Return from Heat Exchanger
3 - Pump to Heat Exchanger
4 - (Obscured a bit) Lowest point in the system, drain for cleaning or emergencies!

That means the whole system can be operated without having to change hose configurations.

Mashing - Wort recycled between 2 & 3, with heat exchanger element controlled by PID
Boil - Stop recirculating until 15 minutes to go, then recirculate to sanitise Heat Exchanger Coil (also switch top valve to sanitise output 1 & Pipe to FV, just back into the boiler)
Cooling - Wort recycled between 2 & 3, cold water forced into heat exchanger to act as a counter flow to wort contained in the coil.

If doing a hop stand recirc until pot temperature is 80c, else carry on until HEX output temp is 20c and then throw the top valve to link 1&2 so return wort from HEX goes to FV instead of boiler.

Top of the HEX with wort and water connections, valve on water in to restrict incoming pressure when using as cooler:



Also found time to put together my brew fridge, STC1000 fit perfectly in some dead space under the lid, so hard wired fridge compressor / heater into it:



Just received sight glass and new temperature probes courtesy of MrLard and some malt should be turning up any minute. First brew day on this new kit tomorrow!

[ajclarkson]

Took the new setup out for a trial yesterday, a standard Pale Ale recipe that I have done a few times before just to get a feel for it.

Generally went well, and it made life a lot easier than my old setup. Pre boil was a little lower than expected, but boil off was far greater so OG ended up high, with short volume. Got 19L into FV at 1.042 was expecting 21L at 1.040.

Have a feeling one of my temperature probes is reading high, so the mash temp could have been lower than it was meant to be. Stupidly forgot to check that!

Dual Purpose Heat Exchanger / Chiller worked really well though. Used it to chill from boiling down to 80c and did a hop stand, then it took about 20 minutes from 80 down to 22 where I started dumping to FV. Seeing as the water was around 17c I was pretty happy with that sort of speed. Whirpooling the return as it came back into the kettle from the chiller did a fine job of collecting the hops and trub in the middle away from my filter, and the resulting wort was crystal clear.

All in all, incredibly happy with my new setup. I'll be brewing again next week, and since I won't be as focused on every little aspect of the system, I'll take a couple of photos too

[beerlover1983]

That is an amazing setup i love it.When are you taking orders

[ajclarkson]

Cheers! It took a while to get together, but pretty happy I nailed the design of it. Not cheap for a BIAB setup with those pricey 3 way stainless valves, but it makes brew day and cleaning a breeze!

[ajclarkson]

Hit an unexpected chemistry based hitch.

The internal pot of the pressure cooker (part that holds the water with the coil in) is teflon coated aluminium. Not that my mind recalled it, but aluminium and copper together leads to galvanic corrosion. So thanks to electrolysis the aluminium from the pot is being corroded and deposited on the outside of the coil. No contamination threat to the wort, but could be a big problem if the pot corrodes all of the way through

I need to brew my Christmas batch tomorrow, and I'm 100% it'll be fine to do so as the process is happening very slowly, but I definitely need to find a solution.

[Fil]

bummer, due to direct contact or just by the water connection, if the former try stripping down and wrapping all metal fittings and pieces with ptfe tape to isolate the metals transfer tape to a drinkingstraw for a small bobbin to thread through washer centres, and to stand the copper off the pot walls an bottom/top try cutting stand offs from thin plastic bottles from the recycling bin, or cut from silicone baking sheet?

[ajclarkson]

Unfortunately due to water connection. I'm going to try making sure the inner pot (aluminium) is totally isolated from the lid though (which is connected to the copper coil) to ensure that there definitely isn't a direct connection.

[ajclarkson]

Took her out for a spin again today. All went well, efficiency was much better than the first trial batch. I even found time for a few photos.

The brew was a new dubbel recipe that I've dreamed up, with 7 different malts (pilsner, munich, wheat, crystal, aromatic, chocolate, special B) and some candi sugar. So of course, it's called Dubbel 07.




Mashing. Thanks to an extra piece of pipe off the 3 way valve, the level sight glass can become an inline sight glass during the mash so I can see the colour developing:



Pull the bag, flip the lid and drop the bag in an old bucket riddled with holes. This lets the bag drain back into the pot and saves my back and arms!



Nice hot break with a dose of Magnum as FWH:



While waiting for the output temperature of the chiller to reach pitching temps its recirculated into the boiler in a whirlpool, does a really nice job of keeping hops/trub in the centre:



Didn't get a picture of it in the FV, was pushed for time but I was expecting 21L at 1.057, I collected 22.5 at 1.057 + 1.6L starter which didn't have enough time in the fridge to decant. Pitched Duvel yeast, not traditional for a Dubbel, but I'm thinking with some temperature manipulating the pear flavours will play really well in this one.