Potable paint?

[Naich]

Interesting discussion. Stainless is out because of the thermal path length. It's OK for loops (if I understand what that is correctly) because the thermal path is tiny (from the inside to the outside of the pipe - about 0.5mm?), but from the top of the FV to the wort will be up to 100mm, then another 100mm or so immersed in the wort. In our cryogenic fridges at work we sometimes use thin wall stainless tube for supports because it is such a poor heat conductor. Either that or fibreglass or carbon fibre.

But I hadn't thought about the lower temperature causing the reaction to slow considerably, of course. I think bare copper is the way to go for the moment, but keeping an eye on the erosion for my peace of mind. I wonder if the tin in lead-free solder would be OK as well?

Thanks everyone.

[mentaldental]

I used a SS product coil to cool my fermenter. The wall is pretty thin so the conductivity is not much of a problem. I use it with a beer line cooler recirculating glycol solution and it does the job.

The coil is pretty open which makes it easy to clean. You can scrub beer stone off easily and quickly.

See this this:

[Kev888]

Stainless is out because of the thermal path length. It's OK for loops (if I understand what that is correctly) because the thermal path is tiny (from the inside to the outside of the pipe - about 0.5mm?), but from the top of the FV to the wort will be up to 100mm, then another 100mm or so immersed in the wort

Just wondered: could you possibly use a stainless fermenter and fix your cooling gubbins to the outside? Would be a very small thermal path and a decently wide area could probably be achieved by increasing the cooler/tank interface area with a thick copper or possibly aluminium sheet. Would also be less to clean.

Not cheap perhaps, but cheaper than a bigger house

Cheers
Kev

[Aleman]

Why use a TEC? It can be done easily with Stainless vessels (More Beer do them on their 'uber' conicals but they fix to the outside wall and cool to 20-30ºF below ambient) . . . And I saw an example that immersed a cooling probe in the wort through the side wall that gave similar results. Seems an expensive option compared to a beer chiller and a stainless coil in the FV ( which are aobtainable ina horizontal as well as vertical configuration).

What you could do is to use your TEC to cool a water bath, and then pump (using an aquarium pump) that coolant round a coil in the FV. Set your water bath temp to just below your desired fermentation temp, and you would have much more gentle cooling in the FV.

[Naich]

I think the stainless coil in the FV is the next step - I did see an advert on Ebay for a cheapo peltier CPU cooler that used pumped coolant, but I can't find it any more. As much as I'd love one, I don't think I can afford the $1800 for a More Beer stainless conical fermenter with all the trimmings

I'm just at the start of experimenting at the moment. The main criteria for now are 1) price and 2) space, so the plan is to initially bodge up something cheap to get some idea of how well it works and then move on to more advanced designs later. I've certainly got it cheap so far - the 80W TEC was about a fiver off Ebay, I've been given a PC PSU to drive it with and I got the heatsink, fan and a load of copper rods out of a skip. Now I just need a nice lump of copper to turn into the right shape to contact with the peltier through the airlock hole. The copper rods will be silver soldered into the turned block and the immersed cooling vanes (scrounged copper sheet) will be soldered to the rods.

Step 1 is to cobble it together, test it out on a well insulated FV full of water and see how far below ambient it goes. Then start refining the design or forget about using a TEC altogether, depending on the outcome.

[Naich]

I used a SS product coil to cool my fermenter. The wall is pretty thin so the conductivity is not much of a problem. I use it with a beer line cooler recirculating glycol solution and it does the job.

The coil is pretty open which makes it easy to clean. You can scrub beer stone off easily and quickly.

See this this:

Cor, I like the piccy. How much was the cooler?

[Aleman]

I use a horizontal product coil like this



Fixed so that it is just under the surface of the wort to try and get a nice cooling convection current set up. You can pick a product chiller up for around 50 quid on eBay

[mentaldental]

I used a SS product coil to cool my fermenter. The wall is pretty thin so the conductivity is not much of a problem. I use it with a beer line cooler recirculating glycol solution and it does the job.

The coil is pretty open which makes it easy to clean. You can scrub beer stone off easily and quickly.

See this this:

Cor, I like the piccy. How much was the cooler?

I got a very old one for free!

[Scooby]

I use a horizontal product coil like this



Fixed so that it is just under the surface of the wort to try and get a nice cooling convection current set up. You can pick a product chiller up for around 50 quid on eBay

Ha, that's the very one I use modified like this and hitched to a chiller that was also free form a local pub that was being stripped.

[Aleman]

I've kept mine in it's flat form, and adjust it so that it sits just (an inch or so) under the surface of the wort . . . much more effective than the vertical one I used to use and a much more uniform temperature distribution in the FV

[Scooby]

I've kept mine in it's flat form, and adjust it so that it sits just (an inch or so) under the surface of the wort . . . much more effective than the vertical one I used to use and a much more uniform temperature distribution in the FV

I can see the logic and as it's easy to adjust the height and form I'll your way

I wouldn't listen to Palmer and Zanesheif too much, they've got to find something to talk about 3 times a week. The majority of their pod casts are just adverts, crap and waffle and sometimes all of it is
.

It's just another point of view to consider. And yes, I find listening to them really hard work.

[Naich]

Good lord Scooby. That is the sexiest fermenter I have ever seen! Even its stand looks beautiful - it's pure brewing porn.

If the OP finds copper cheaper and easier to work with, i'd stick with that

That's the latest plan. Still looking for a nice bit of copper to turn up, but as plan B I've got a scrag-end I could solder the rods to, which I could feed through the airlock hole with a small bit of 8mm pipe, to make contact with the peltier cold plate clamp. There's no hurry at the moment because the FV is still in use. Nice piccy of a copper fermenter. How do you steralise something that big? Is there some trick or do you just use lots of steraliser?