Sous Vide on the Cheap

March 23, 2011 · 14 comments

Homebrew Immersion Circulator

My first experiment with extended-time constant low-temperature cooking – commonly referred to as sous vide – involved creating a “ghetto” rig out of a deep pot, a steamer basket, and a wire colander, all set over my stove’s simmering burner. I monitored the temperature with a probe thermometer and made adjustments by raising and lowering the heat on the burner. I had, in effect, created an analog model – with a very slow response curve – of a professional immersion circulator that could cost a thousand dollars.

Last year I graduated to a Sous Vide Supreme, a home appliance version of the pro water bath. It relied on convection instead of active circulation to maintain a constant water temperature, which meant that adding too many bags to the bath could result in uneven heating of the contents. It would level out over longer cook times, but if you only needed a few hours of immersion, uneven cooking could be a problem.

I wanted a real immersion circulator, but people had already wised up to deals on eBay, driving the prices up to those of new units. To make matters worse, some readers of this blog (I’m looking at you, MS) thought that gloating about their bargain-priced eBay finds would somehow make me feel better about my “kitchen toy.” I resigned myself to saving up for the real thing, figuring it would take about a year for me to come up with the scratch.

That all changed when the newest issue of Make (number 25) arrived. Right there on the cover it said “Sous Vide Cooker.” I read the article (expanded from a year-old blog post by the author) a few times, then decided to commit: for less than $100 I could wind up with a real immersion circulator.

Before I describe the build process, it’s important to understand that although I got my degree from MIT, I am not an engineer – I’m a biologist. I can read simple circuit diagrams, I know how to use a soldering iron, but that’s from my childhood electronics hobbies, not any formal training. So I approached the project with a certain amount of trepidation. There was a very real possibility I would screw it up.

The build plan is detailed but clear. I ordered all of the key components, knowing that I’d have to wait a few weeks for some of them to arrive via airmail from Hong Kong. (If you go to Amazon for any one of the parts, you’ll see that all of the others are grouped under the “people who bought this also bought” category. The day came when I had everything ready: an acrylic box (I ordered four of these, for reasons that will soon become evident), three cheap immersion heaters (which an English friend described as “essential parts of any Brit’s foreign travel kit”), a PID controller (the brains of the device), a thermocouple temperature sensor, a power switch, a solid-state relay, and a miniature submersible fountain pump. I didn’t know what half of these things did; if I was told I needed an aperture flywheel gromis with a rotary gasket, I would have bought one of those (without the wing nuts, of course).

Next came the most difficult part of the entire project: cutting and bending the plastic. The author just happened to have access to a laser cutter, but I would have to rely on more primitive tools since a CNC lathe is low on my wish list. I began with a drill and coping saw, and immediately proceeded to shatter the lid. Hearing my insulation-scorching imprecations from the basement, She Who Must Be Obeyed offered to consult with one of her colleagues about the best way to cut acrylic. The person she asked (who embodied the geek/know-it-all trifecta: ex-Navy, ex-Polaroid, and ex-MIT) recommended that I buy a Dremel tool and a cutting bit. It would up my project expense by about $80, but it would also preserve my sanity.

I spread the cutting out over two days, working on the lid, then the main box, and finally the clamp. After a lot of cutting, bending, gluing, and fastening, I had the heating elements and the pump in place.

It was all smooth sailing from that point on. I attached the thermocouple and pump, wired up the controller and relay, and sealed up the holes with silicone cement and hot glue.

I made room for all of the wiring and closed up the box, sealing the lid with electrical tape until I tested the unit, after which time I would glue it shut.

All that was left was to attach the circulator to a tub of water and turn it on. After a bit of button pressing to set parameters for the thermocouple, I had a working device. The orange LEDs display the desired temperature, the green display the measured water temperature. The little green light indicates that the heaters are on.

$75 fo the parts, $80 for the Dremel, and another $20 for the tub, for a total of $175, a far cry from the $900 I expected to have to spend. Now that I have more room to cook, I’m already thinking about whole fish, rib roasts, maybe even an entire pork shoulder for pulled pork. I’ll be sure to post the results of my experiments here.

14 comments

Diane, She Who Must Be Obeyed March 23, 2011 at 8:47 pm

And it is a thing of beauty in action!

Rose Fox March 24, 2011 at 12:15 am

Do you take commissions?

David March 24, 2011 at 11:13 am

Possibly. Let me get the bugs worked out of this one and we’ll talk.

Michael March 24, 2011 at 3:59 am

David, you are brilliant. And I don’t mean that in the British sense where every friggin thing is brilliant this and brilliant that. I mean you are, literally, brilliant.

David March 24, 2011 at 11:08 am

I might be brilliant if I had come up with the idea. Since I only implemented it, I’m at best merely clever.

Peter March 24, 2011 at 7:58 am

That’s awesome. I have a water bath (non-circulating) that I got on ebay years ago, but this looks like so much fun I might do it anyway.

David March 24, 2011 at 11:10 am

If your water bath is accurate and reasonably responsive to temperature changes, you could just buy the fountain pump and glue it to an interior wall of the bath below the fill line. That would provide you with the circulation you needed.

David Dallow March 24, 2011 at 10:25 am

Wow! Impressive. I read that blog post repeatedly to see if I could pull that off but had visions of people shaking their heads reading the newspaper headlines of my electrocution.

I looked on ebay as well but was warned that some circulators were not calibrated properly and could be imprecise. I wanted the SousVide Surpreme but was put off by the smaller cooking space. I could never use it for entertaining.

Then I saw Williams Sonoma began carrying a PolyScience circulator, for under $800. I set my wait/save time at a year as well. I pick it up this weekend and am giddy like a kid on Christmas.

Can’t wait to see your further experiments and applaud the DIY spirit.

David March 24, 2011 at 11:13 am

I’m not quite ready to cook with the thing. I’m running a series of temperature measurements, plotting actual water temperature against reported temperature. They’re off a bit, so I have to figure out how to program a slope correction into the controller. It’s not completely necessary, I could get by with bumping the set temperature up or down until my water temperature is correct, but that requires to much fussing at setup time.

Andrew March 24, 2011 at 1:20 pm

Nicely done, David. I saw those instructions a few weeks back, and thought maybe someday I’d make this, except I knew that mine would come out looking like it was assembled by a 5-year-old, even if it worked. So far, my 48-cup rice cooker / controller set up is large enough, but if you decide to work on commish, I’ll probably sign up for one anyway.

David March 24, 2011 at 4:54 pm

Perhaps we could work out an exchange: you buy the parts, I’ll build it, and you can give me a few bread-baking lessons.

Andrew May 20, 2011 at 7:03 pm

I’d be glad to make the trade, David. Word is you hooked Peter B up with one of these. If you have specific bread learnin’ needs, email me and we can set something up. I’ve been teaching semi-regular classes in my kitchen to show people the ropes, should be doing another in June, if you are interested.

Phyllis March 26, 2011 at 7:39 pm

I’m really impressed. Wow.

David March 26, 2011 at 7:41 pm

I’m sure Ron could throw one together for you.

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