Sous Vide

Nomiku

I got a sous vide immersion heater/circulator just before Thanksgiving, and I’m loving it.

Sous vide is a method of cooking that involves putting food in vacuum sealed bags, and using heated circulated water to cook it, usually at relatively low temperatures for relatively long periods of time. It used to be the sole domain of restaurants, and sous vide cookers are usually large and expensive. But there are now a few home units that are affordable. I picked up a Nomiku when it was a Kickstarter campaign but they can be ordered now for about $300.

That’s a lot of money for a kitchen gadget, but this one is going to get a lot of use in my kitchen, and it’s a bargain compared to the $1000+ commercial units. I was going to build one using an immersion heater, an aquarium pump, a thermocouple, and a PID controller. The parts would have been less than $100, but I was going to have to build an enclosure for it and find a suitable container for the water bath. And I’d have to tune the PID controller to keep it accurate.

The Nomiku was more expensive, but it was more convenient. It clips on to the side of a stock pot, so it packs away nice and easy. It’s easy to use – plug it in and turn the knob to set the temperature. It circulates the water in the pot, heating it up to and keeping it within 0.2 degrees of the target temperature.

So why is this useful? Because it lets you bring the temperature of your food to precisely the temperature you want, which gives you better control over how the food turns out.

Why? Well, it has to do with the reasons why we heat food before we eat it (otherwise known as “cooking”):

  1. Most food tastes better when warm or hot (above room temperature, if not above body temperature).
  2. Proteins transform when heated, creating more appetizing texture.
  3. Food borne bacteria that can make us sick die when heated.

Unfortunately, the ideal temperature for each of these does not necessarily coincide. Generally, the goal is to get all three of the above to at least the minimum necessary temperature in the center of the food. The first two are usually achieved before the third, so we’re usually trying to reach a “safe” internal temperature. Which unfortunately means we tend to overcook the food in order to make it safe.

To minimize this effect, we try to reach the “safe” temperature as quickly as possible. But you can go the other way and go low and slow. You can often achieve desired results by holding the food at lower temperatures for longer periods of time.

Salmonella (for example) dies pretty darn quickly at 165° F. But it dies at 140° F after 12 minutes, so if you’re not in a rush, and your proteins set to a nice consistency at 148° F, you don’t have to go all the way to the usual 165° F.

The two downsides of sous vide cooking are:

  1. Fatty proteins (particularly poultry or pork skin) will not get hot enough to render the fat.
  2. The food doesn’t get hot enough to brown.

The usual solution to both of these is to brown the food on the stovetop or grill after cooking. Of course, you don’t want to overcook the food, so I suspect it’s best to remove fatty skin in the first place.

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The first thing we cooked with the Nomiku was eggs. I’m not a big fan of eggs (long story) but the way I’d heard sous vide boiled eggs could be cooked to a custard-like consistency and I might actually like them. The yolks were nice, but I still didn’t care for the whites. And the 1-2 hour cooking time is a bit of an issue for cooking eggs. The missus still boils her eggs on the stovetop.

But Thanksgiving was a good opportunity to try sous vide cooking turkey. We got parts instead of a whole bird, and cooked them individually with some apple cider in the bags as marinade. It turned out nice – very moist (it doesn’t get hot enough to boil out the internal water) and it has a nice flavor and texture – especially the dark meat.

With a short bit of browning, it even looks like roasted turkey:

Thanksgiving Dinner

We’ve been experimenting with chicken thighs this week, and it works very nicely. 148 ° F for 2 hours works, but 4-5 hours gives it a better texture. Since the water inside the thighs doesn’t get to boiling temperature, the juices stay inside the meat. The proteins form a matrix that helps hold the juices in even when you slice it. And at this temperature, the meat is nice an tender and has just enough “give” to it. It’s like al dente chicken. And it keeps nicely in the fridge and makes good fodder for sandwiches, salads, and lots of other uses.

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