I know that I am not supposed to trust my oven's internal thermometer and I should purchase a separate oven thermometer to make sure I am at the correct temperature. But how do I know if the oven thermometer is correct? I had an oven thermometer and it indicated that the oven took a lot longer to get up to temperature than it said it did (5-10 minutes beyond the beep). However, eventually it got up to the correct temperature. Well my thermometer broke and I replaced it and the new one indicates that my oven is about 30 degrees too hot. How do I know which one is accurate?
there is a way to calibrate your oven using sugar as sugar behaves differently at different temperatures. i've found a webpage that gives the details;
ucbc, I periodically put them all in the same oven. The ones in the oven that are spring driven are slower to register. I always preheat to the independent one. By the way, when I had my oven repaired, the serviceman's thermometer was off by 30 degrees. He said they never calibrate them. And this was on my KA true convect! He ultimately used my little row of Walmart thermometers to check my calibration. He was sorry he said I was wrong when I got finished. He told me my oven was fine and I told him to take them out of the wall and put it in the dumpster. It was new. The temp was ok, but the relay was broken, causing it to swing 50 degrees (25 up and down) from the stated temp. He said that was industry standard. I told him that was what he was told to say, not standard. I got my new motherboard. This was a huge issue that had me stumped because the thermometers would not register the change. I just had soggy middles and I could not figure it out. His computerized thermometer did register that. So if you are ever really stumped, have a repairman register the variance.