07 Youngs Harvest Barley Wine - Water BathThe Waterbath, A big container:
I use a storage box got from a discount store, in use it has foam around the outside and a sunlight heat protector on top, reflective foam piece you put on car windscreen to stop sun baking insides of car. Works to keep heat in the tub. A big black bin would work just as well, probably be big enough to enclore it up tight as well. Fill with bleach containg water to stop growing undesireables. Large water mass helps to regulate the temperature of the fermenting beer.
Temperature Controller:
Most important part. I use a ATC 800+ for eaby, wired to turn on the heater and pump at the same time. It is cased in a foxes biscuit box as appearance dont matter. Keeps it nice and neat.
ATC800 ManualATC 800+ is a bit expensive, nut you can get cheaper units like the STC 1000 nowadays. Its about €16 and 1/2 the size. They are popular to use in kegerators as well.
Aquarium heater:
A 50w stainless steel covered unit from ebay. Stainless steel to stop it exploding if it comes out of the water while still on for whatever reason. They appear to be quite hard to find on ebay.ie right now.
A similiar one but 100w €7.20 inc P&P
Larger heat does not make much differece that the 50w, lenght is the big differece mine is 9" while this is 11".
Heater is set high temp usually about 30°C, but is controlled by the temperature controller. So it only gets to what you set it. I just heat the water as ambrient temp even in the portacabin do not rise the water mass above set temperature. Then let it cool at its own rate.
Aquarium Pump:
This is mainly to just make the water flow around the waterbath evening out the heated water so you don't get really hot near the heater and cold on the otherside of fermenter. Any cheap submerged pump should be fine. All we are doing is moving water about.
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You could probably use a big thermowell, a capped pipe into the wort, and just put the heater there with the probe in another well. Well have to be filled with water or vodka to function, esp the heater one if this idea was tried. Main argument against this is the wort is static and heating would not be even.
wall of Info