I cooked ball tip steak (2" - 5 cm thick) with my Anova Developer Preview unit at 55 °C for 12 hours. (No, you don’t really need that long time, though connecting tissues, which are part of this cut of beef became soft, and the meat itself was quite perfect - so it was not just a technical experiment.) I measured the temperature and took timelapsed photos of the unit with my RaspberryPi rig.
Time consistency was excellent (far better than needed for cooking). The temperature, measured by my RPi, fluctuated between 54.44°C and 54.50°C and never dropped below or raised above these points. (I can’t claim that my DS18B20 temperature sensor is calibrated better than Anova’s so I didn’t pay attention to the 0.5°C difference between my and Anova’s measurements.) Here is the temperature chart:
The energy consumption by the unit was 1.76KWh (it means it was using 146.7W on average).
About 0.7l of water evaporated from the 8qt uncovered Cambro box (of course, it depends on the geometry of vessel - but something to take into account for long cooking).
As for the culinary result, here is a picture:
I have few questions for you if you have a minute:
-Where can I learn more about your amazing sounding rig?
-The beef looks great; did you torch?
-Sear/torch before bathing or after?
-Have you tried plastic wrap to create a seal over your container and around the Anova; is there something wrong with me doing this?
“The rig” is RaspberryPi board (the older one, with 2 USB ports) with 2 DS18B20 digital temperature sensors: one waterproof for water, and another for room temperature - connected via cobbler and breadboard. It also has a camera and WiFi/BT stick (I was planning to use Bluetooth to interact with Anova, but didn’t realize that BT3 won’t work with BT LE).
<img src=https://lh5.googleusercontent.com/ijWfkTpMLUH0U8PhCweCiDYPwNTqftonklKc0J4oj2po=w1204-h903-no>
The temperature sensors record temperature log using cronjob, as well as report temperature on web interface:
Camera is also controlled via web interface (and was set for 10 minutes time lapse):
Yes I torched with BernzOmatic. I am patiently waiting for my Serzall to arrive.
Usually, I prefer to torch both before and after bathing (a little before - to get some Maillard aromas to permeate the meat, and after - for esthetic reasons and to reduce fat). In this particular case it was a prepacked steak in sauce and I was lazy enough to sous vide it as is (so I torched it only after the cooking).
I don’t think using a plastic wrap to reduce evaporation is a bad idea. I actually got the covers for Cambro box with the intent to cut out hole for Anova. (I do have a Restaurant Supplies store nearby - Internet prices are quite unreasonable.) From my experiment I see that evaporation is not such big of a deal (it’s not too difficult to add few cups of hot water once in 12 hours) so the covers stay unmolested for time being.
[From my comment to another discussion about effectiveness of Anova as water heater:]
I measured the heating of 5.5l of water from 20C to 70C. It took 32 minutes and 0.37kwh of electricity. This means that thermal efficiency was 86%. The induction cooking claims around 90%, regular electric stoves - 60-70%, gas stoves - 30-60%. (5.5l50C=275Kcal=0.32Kwh=0.860.37Kwh - for those who want to follow my calculations.)
@Anova2Cook No it does not. These were two separate unrelated measurements. 1.76KWh was for 12 hours cooking at constant temperature of 55°C (and other conditions described there in details); 0.37KWh was for heating 5.5l of water from 20° to 70°C.
Very helpful post, thanks! It certainly gives me higher confidence in the unit’s ability to maintain a given temp accurately. I have had similar experiences over 48-hour chuck steaks at 142.0ºF with absolutely no waivering at all according to the Anova display, and occasional checks with two Thermopens. I used an 8-quart Dutch oven and covered it with aluminum foil; over the 2 days I lost only 1/8-inch of water through evaporation. I like the foil better than plastic wrap since it is easier for me to open and reseal periodically.
