When pressure canning, food is usually held at temperatures up to 120 degrees. Some recipes use lower temperatures, so it is very important to pick a DS18B20 sensor that can work at that temperature. According to the spec this sensor works up to +125 degrees, but in real life far from every sensor from China works properly at 120. I have several sensors: some bought ready-made on AliExpress and several that I built myself from AliExpress sensors. All of them worked great in distillation and rectification. When I started testing them in the autoclave, all the homemade ones held up fine, while the very first ready-made one failed immediately. I did not torture the other ready-made ones, but the idea is clear: build the sensor yourself, do not buy the cheapest one, read the reviews. Even so, you may be unlucky. On the other hand, they are cheap, so if not the first, then the third attempt will work. When building one, it is important not to forget to put thermal interface material into the sleeve between the tube and the sensor. I used a neutral heat-resistant sealant, which is more than enough. You must not use an acidic one, it will corrode the wires. I did not bother with hot-melt thermal glue: if something happens to the sensor, thermal glue is much harder to remove. The autoclave well where we place the sensor also needs to be filled with thermal interface material. In my opinion, glycerin is the most convenient for this.
So, the sensor is made and connected to the Samovar.
Now we set up the Samovar:
1. Choose Settings/Main/Operating mode/Beer. Save; the Samovar reboots and switches to “Beer” mode.
2. Settings/Temperature/Boiler sensor address. Make sure the address of the correct sensor is set here, or specify the correct sensor in the Beer program.
4. Program. Here we set the temperature and the time to hold it. These values may vary a little depending on what you are preparing. The classic is 120 degrees for one hour. Set the PAUSE mode, temperature 120 degrees, time 60 minutes. Practice has shown that the risk of damaging the jars and of the contents boiling over is lower if you do not heat to 120 degrees as fast as possible in ramp-up mode, but gradually over roughly half an hour: I make steps at 105, 110 and 115 degrees and hold for 3 – 4 minutes on each step. The resulting program looks like this:
P;105.00;4;0^0.00^0^0
P;110.00;4;0^0.00^0^0
P;115.00;4;0^0.00^0^0
P;120.00;60;0^0.00^0^0
That finishes the setup: press the “Set program” button, turn on the heating and enjoy the automatic process until it ends.
One more recommendation: replace the Chinese pressure gauge that comes with every autoclave with something decent. You can fit a calibrated Rosma gauge, 63 mm diameter, with a 0.25 MPa range. You can buy it on Ozon. It is very convenient to use in the working pressure range of an autoclave.
The original article is here.