How to check oven thermometer accuracy?
I have a suspicion that oven is inaccurate and have an in-oven thermometer which reads the same as the temperature set on the oven dial, however how do I know if this itself is accurate? What is the best place to put it?
Initially I placed it at the edge of the middle rack so that it would not interfere with pans which were put on the rack itself but in that position I noticed that it was always reading very high and realized that it was directly over the slit on the side where the heat comes through so I moved it as close to the middle as I could without obstructing the area on the rack itself and so now it reads the same as the dial but everything seems to take forever to cook or at least longer than I expect.
How about checking the oven?
An appliance repairman told me (when I asked about having an oven checked and calibrated) to buy some of the biscuits in a tube and follow the directions, but make sure to preheat the oven for 20-30 min. Then, see if they bake within the time specified. If the baking time is off, adjust temperature and repeat.
I actually did this recently with my new oven and found after baking, adjusting temp, waiting for temperature to adjust and baking again. Each time I used 3 biscuits. I found a 15 degree adjustment worked well. It worked on the baking I did after that.
If the timing is too far off, then you may have to get it calibrated, but as the repairman told me that takes some time so can cost more than you might expect.
Browned and after a couple minutes resting cooked inside, but not dried out. If it is very brown or burnt after 11 min, then it is too hot. Mine after 11 min were a little pale, but not white. So I raised the temperature a little.
I found it worked well - if I could tell within 15 degrees. If you think the oven is not even then use more at various end of a cookie sheet. Don't use a thin cookie sheet.
The biscuits are cheap enough that you can experiment. You might post this under cookware. I have never had any luck with oven thermometer.
I have never used the sugar method - looked it up and I have no idea if it works. I would guess you have to use a good container. Every oven cycles. If it is not cycling correctly due to thermostat (which is what you are trying to check) or even insulation, then baking with something standard like the biscuits will tell. It is true some ovens are ok at 350 degrees, but go off at 450 and this will not tell you this.
Put a bowl of water in it, and set the oven to 212, and see if it boils , or if it boils sooner than the set temp is reached. If it doesn't boil , then you can adjust from there. Of course altitude will be a consideration.
You can also get a digital thermometer and test it. Maverick makes a few. The ET 732 is popular in bbq circles.