Wednesday, October 2, 2013

Nomiku Immersion Circulator

I was first introduced to sous vide back in culinary school, but it wasn't quite the same technique that's popular today.  Sous vide is french for "under vacuum", and what they covered in class was the "boil in bag" method of vacuum packaging pre cooked items at a central commissary to be reheated on site by immersing the bags in simmering water, unbagging and plating.  The sous vide technique that's popular today is a low temperature cooking method where items are vacuum bagged in a raw or almost raw state and cooked by immersing in a water bath maintained at a precise temperature using rather specialized equipment.

Back in 2009 I first became interested in playing around with the low temperature version of sous vide.  I started lurking around on Ebay until I was able to pick up an old Fisher Scientific immersion circulator in 2010 at a good price.  It was pretty dirty when it arrived and needed a lot of TLC to get working.  I took everything apart, cleaned all the electrical connections, descaled and scraped off a lot of gunk and was rewarded with a (mostly) working immersion circulator.  I say mostly because there is some issue that I haven't been able to remedy which causes the circulator to trip any GFCI protected outlet, like all the outlets in the kitchen.  Because of this I had to do all my sous vide cooking out in the dining room.  I wanted something a bit more reliable and modern, but new immersion circulators suitable for kitchen use were all in the $500-$1000 range.  That changed in June 2012 when a Kickstarter campaign started for a low cost immersion circulator for the home cook called the Nomiku.  For a mere $299 contribution a backer would receive one of the first Nomiku units, which were supposed to ship out by November 2012.  I jumped at the chance, knowing that there was no guarantee I would ever see anything.

The Nomikus were originally estimated to ship in November 2012, but that month came and went with no Nomiku.  The founders of the company had to deal with repeated delays, changes and roadblocks along the way but they persevered, and on October 1st I came home from work to a brand new Nomiku sitting on my doorstep!

The Nomiku is a much more attractive circulator than my old Fisher Scientific model, it consists of the circulating/control unit and a separate power supply.  In the box is a user manual, an illustrated "getting started" sheet and a sous vide primer.  The circulator feels solidly built, the only thing I noticed was that the green ring that you rotate to set the target temperature seems a bit loose but that seems to be by design.  I grabbed a large stockpot (about 28 quart capacity), attached the Nomiku and started filling until the water level reached the "Max" level indicator on the stem of the Nomiku.  That took 14 liters of water.  Normally I would fill the bath with hot water from the tap, but since I wanted to stress the unit to shake out any bugs I used cold water (about 20°C).  The reason I like to stress new equipment is that it allows my to find any faults early on that may require the item be replaced while still under warranty.

As the inaugural dish I decided to make sous vide carrots, this required a 90°C water bath that should be the hottest I'll ever need.  After filling the bath with the 14 liters of 20°C tap water I plugged in the Nomiku and tapped the screen to turn it on.  The desired bath temp is set by rotating the green collar around the screen, which I did until the display showed 90°C.  It took a LONG time for the bath to heat up.  At the 2 hour mark we were just getting up to around 76°C, so I tried to improvise a lid to help reduce the effects of evaporative cooling.  That helped, but I needed something a bit more effective so I ended up covering the pot with s sheet of aluminum foil and covered that with a dish towel.  That turned out to be effective and by the 2 hour 40 minute mark the bath had reached the desired 90°C temperature.  I made a simple preparation of carrots, just the vegetable, some butter, a little cumin and salt.  This was bagged using a Food Saver Vacuum Sealer and dropped into the bath for about 20 minutes.  As long as I had the foil top on the pot the Nomiku was able to maintain the bath temperature within +/- 0.1°C of the target point, I could see the light over the stove dimming as the heating element cycled.  Once the 20 minuted was up the bag was removed from the bath and I lowered the set temperature on the Nomiku to let it start cooling down.

If you've never tried sous vide carrots I suggest you give them a try.  The technique allows all their natural sweetness to some out and they retain an intense flavor.  The Nomiku performed like a champ, I think I can definitely get by with a smaller bath size for most applications and finding a bath container with a cover that I can cut to accommodate the circulator unit will help reduce the energy spent maintaining temperature.  Since I will be able to use my Nomiku in the kitchen I'll be able to pre-heat the bath water rather than let the circulator do that extra work on its own.  Now that I have a circulator that is so much easier to set up that my old one I'm going to be able to really play around with sous vide cooking.

One of the things I often hear from people is that sous vide cooking of meats is dangerous because you aren't raising the internal temperature to what the USDA recommends.  People need to understand that the USDA recommendations are based on a short exposure time at that temperature while pasteurization is a function of both temperature AND time.  A longer exposure at a lower temperature will kill pathogens just as well as a short exposure at a higher temperature.  Douglass Baldwin has an excellent sous vide guide including pasteurization tables located here.

Visit the Nomiku website for more information.

Edit:  I heated up another bath of 14 liters from 20°C to 90°C with the pot covered in foil and a dish towel from the start, this knocked almost an hour off the heating time (1 hour 45 minutes down from 2 hours 40 minutes).

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