Into The Vide

March 1, 2011

You Shouldn't Be Rapping
This week’s mad science news is that I’m starting to experiment with sous-vide cooking now that I’ve gotten around to building myself the necessary tool to do that, uninspiringly referred to as a sous-vide cooker.
The idea of sous-vide or “vacuum-sealed” cooking is that you can achieve various interesting results by cooking things at low and often quite specific temperatures for much longer periods of time. Eggs can actually be poached in the shell, for example, and meat of any thickness can be cooked to perfect medium rare all the way through before a quick searing on the grill to finish and serve.
It turned out to be pretty straightforward; you can use a slow cooker, but if you have a pot and a wall socket you can get the rest of the way there for about $100 in parts. While the resulting tool won’t get you all the way to the tenth-of-a-degree precision that professionals may insist they need, you can get an accuracy of plus or minus one degree for fraction of the cost.
That will be a familiar experience for anyone who’s ever bought professional lab equipment, no doubt; want that extra shaving of a decimal point’s worth of fractional accuracy? That’ll be a 20000% premium, please. Fortunately for me amateurishness can be pretty easy on the budget, at least in the short term.
This has been interesting reading, including the temperature charts that I was soliciting on twitter the other day. I’ve also been looking at this list of food temperatures from Health Canada, and a comparable U.S. Government food safety page with a just slightly jaundiced eye, as their tendency to err on the side of cook-until-rubberized is understandable. Even more unfortunately, most of the other sites I’ve found have all the familiar hallmarks of trending-term content farmers, and no.
Nevertheless, a quite high quality of ingredients and information about temperatures and times is important when one possible failure mode is the E-Coli-A-Gogo version of the Sea Monkeys Home Aquarium and a night in the ER vomiting out your lungs. Did that image dissuade you? It’s OK if it did, this isn’t for the culinarily timid or faint of gut. If not, excellent, let us press on; just don’t be doing this with discount meat, you know?
Assuming you have a medium-to-largeish pot to hand, you really don’t need much:

  • About a meter of loose extension cord wire and separate male and female ends you can attach it to. Three prong, please. You can pick this up at your local hardware store for between five and ten bucks, horribly overpriced at that.
  • A dozen or so smallish marrettes just to cleanly tie it all together. Hardware store, likewise.
  • The parts that your hardware store won’t have are a Temperature Controller, a solid state relay, and a thermocouple. Those links go to the places I got mine, and I was pretty happy doing business with them – they insisted on a shipping method with a tracking number to ship to Canada, but their prices were a lot better than I’ve found elsewhere, so.
  • A standalone electrical element like that one, and a wire rack of some kind that fits in the bottom of your pot. This is the part you can substitute with a non-digital slow-cooker (and possibly even a rice cooker?) if you’ve already got one of them.

I won’t go through the step-by-step of wiring all of that up, but email me if you like. The basic idea is this: power comes from the wall and goes both to the temperature controller and through one side of the relay. The other side of the relay, the control circuit part, is likewise wired up to the temperature controller (the documentation for that thing is here) as is the thermocouple. What you’ll end up with is essentially an extension cord with a thermometer switch; it switches on when the temperature drops below some value and off again once you get back where you want to be. You should clip the thermocouple wire to the side of your pot with a clothespin or something so it doesn’t touch the bottom of the pot, or your readings will get a bit skittish. The wire rack is just to keep the zip-lock freezer bags you’ll be using from touching the hot bottom of the pan directly.
That’s about it. The only thing I have left to do is to find myself a reasonably pretty project box for the whole assembly – right now it’s a little inelegant with all the wires hanging out, but it works like a charm. I’m going to be trying something a lot like this out tomorrow night, just to see what comes out the other end of it, and I have it on good authority that butter-poached ribeye is one of the greatest things in ever.
I’ll keep you informed!