Due to a couple of successful Kickstarter campaigns I find myself with two kitchen gadgets which offer to provide a temperature controller waterbath for sous vide cookery.
They each take a different approach to the challenge of providing a constant temperature waterbath, so I thought it was worth comparing them.
How they work
The Nomiku is essentally a stand alone gadget. You clip it to a pot of water, and turn its big green knob to set the temperature you want the water to maintain. It then sucks in water, passes it over a heating element, and pumps it back out. It can control the temperature of the bath by monitoring the intake temperature of the water.
The Codlo works by controlling an attached slow cooker or rice cooker, and using a temperture probe to assess the temperature of the bath.
Both can be set up pretty quick. Assuming you have the equipment to hand it takes no more than a minute to have everything ready to go.
Then you wait for the water to come up to temperature:
With a 1KW heater built in, the nomiku takes less than 10 minutes to get 6 litres of tap water to 53˚C - the optimum temperature for a medium rare steak.
The Codlo depends on the power of the cooker you have plugged into it. My slow cooker is an old no-name one, and I guess just doesn't have the power required for the job. After 40 minutes I gave up and added some water I heated up in the kettle.
In addition, with the Nomiku it'll maintain the target temperature until either the water gets too low (e.g. due to evaporation) or the power gives out. The with the Codlo you set a timer, and the device will switch on an off as appropriate.
Do they maintain the target temperature?
In comparison the Codlo suffers. The Nomiku actively circulates the water. The Codlo merely turns heat to the pot on or off... so is subject to hot and cold patches in the water. It also can't rely on almost instant changes in the heat applied to the water as it is beholden to the thermal characteristics of the pot it's controlling. It tends to overshoot and undershoot its target temperature much more than the Nomiku does.
When you drop in your cold food, the temperature of the water drops. With the nomiku it gets back to where it should be in a minute or two. With the Codlo it takes 10 minutes, then overshoots, undershoots... and eventually settles. Again - this could be because of my rather arthritic slow cooker.
In steady state they both maintain reasonably well. The Nomiku is never more than 1/2 a degree off, the Codlo stays within 5 degrees either way.
What would I recommend?
If I'm cooking sousvide, I use the Nomiku every time.