Lately, I've been experimenting with sous vide cooking. Vacuum seal the meat, drop it in a cooler with some water (I already have calibrated my cooler, and I have a thermapen). My setup loses some temp over time, so it's really the quickie sous vide that I can do right now: 60 minute steak or eggs, stuff like that. I want to build a regular recirculator.
At the same time, I'm dealing with mash temp control on my current brewing setup. Moving to a bigger system means direct-fire mashing is something of a PITA. I'd rather heat things to strike temp with my gas burners but then move to a set-and-forget electric system to hold mash temps.
Seems like I ought to be able to double up on these things. The hardware needs to accomplish the same thing: hold a liquid at a constant temperature for an extended period of time. I would like some advice before finalizing my design, though. Here's what I've got.
Currently my brewing setup is a 1/2 bbl thing based on 30 gallon pots, direct-fire gas burners. It's a 2-tier system with the HLT high and gravity feeding down into the MLT during the sparge. I have a single march pump for transfers and recirculation. In the three brews I've run on the system to date, I've been able to hold mash temps relatively constant without too much wild swings, but it's a big pain.
I've got a PID, thermocouple, and SSR on order. What I need to figure out is what to hook things up to. I'm also handy enough with wiring and construction that I'm confident I won't electrocute myself or the mash. Right now I have two basic ideas.
Thing one: a direct-heat system. I box up the assembly either as a single unit or maybe split into controller / heater units separately, with a heating element sticking straight out of it. It would look something like this
, although probably with a LWD water heater element instead (and like I said maybe have the controller box separate). I could attach this directly to a medium sized cooler for sous vide, or find a way to run wort over the heating elements during the recirculation for mashing.
Thing two: a HERMS getup. I could work with my old five gallon pot and convert it to a HERMS setup. The heating element would be permanently mounted to the bottom of the pot and there'd be a coil for heat exchanging (either copper or stainless, depending mainly on budget issues). When mashing, I'd use it just like a normal HERMS system (although unlike traditional herms getups, I wouldn't be using the HLT as the HERMS vessel). When cooking, I'd just suspend all the food in the water bath itself. Theoretically, I could probably make the coil into a convenient basket shape so it would hold the food bags easily (and keep them off of the hot water heater element.
My current thinking is that the HERMS version is probably more likely to be useful and effective, but the RIMS version would be a lot cheaper and easier to build.
The third way I was thinking about it would be to just build a straight-up RIMS tube thing. I could either circulate wort through it or water. That's also pretty simple.