Lately, I've been experimenting with sous vide style cooking. That more or less boils down to (hah!) vacuum-sealing some food and putting it in a warm water bath that holds at 110-170° F for a few hours. For now, I've been using a well-insulated cooler and just swapping water in and out as needed to hold temps. I already have a foodsaver vacuum thing for packing up hops, plus a thermapen for good temp readings. Things went pretty well in the initial runs, but I'd really like to be able to fire-and-forget: set up the sous vide stuff when I get home from work (or before I leave) and have it ready to go a few hours later for dinner.
An actual sous vide machine (just a water bath thing with a good temp control panel) costs about $500 or more, which I'm not in the mood to spend. DIY time.
Some people just use a PID to control a crockpot or rice cooker, but I thought a heating element naked to the liquid (plus a heating element is a fair bit cheaper than a rice cooker and more flexible). I was in the middle of designing a DIY sous vide system when I realized that I was basically building a herms or rims setup. I need to use a PID to control a heating element to hold my liquid at a sub-boiling temperature for a long time.
That's when I decided to try and design this thing to be dual-purpose. What I want to build is a Device, that when hooked in line to my mash tun recirc system will hold the mashing wort (what's liquid that's halfway between sweet wort and liquor called?) at a constant temp (152° F or whatever) and when not being used to mash can be relocated upstairs to the kitchen for sous vide duties.
At this point, I have two competing designs. One is pretty much just a HERMS pot- an electric heating element attached inside one of my older pots, with a stainless heat exchange coil running through it. I can arrange the coil such that it acts as a basket so the plastic bags of food don't rest directly on the heating element, and just use the pot as the heat bath as needed. An extra inlet and outlet at top and bottom, and I can recirc the clear water during sous vide to keep even heating (might also do that during the mash, but that would require a second pump).
The second design is a much smaller Box that has a heating element and thermocouple sticking out of it. The entire Box sits on top of an open pot (or insulated container) such that both are submerged. This can be attached to whatever pot I need to heat sous-vide style. It has the benefit of being a bit more useful for actual sous-vide duties (as it can be attached to whatever size pot is needed for the food I'm cooking) but less useful for mashing. I'd be able to cook up a RIMS tube, more or less, for mashing.
In a related note, why are all RIMS tubes made of stainless steel? The designs I've seen all work out to be pretty expensive just for the tube and various attachments. All one really needs is a heat- and chemical-resistant foodsafe enclosure for the liquid to be run over a heating element in. I imagine I could build one of those a lot cheaper than those fancy triclover getups. On the other hand, stainless triclover is prettier (and a bit easier to clean) than an aluminum pot.
Anybody do anything like this? Advice from both sides (HERMS/RIMS design and sous vide) welcome.
