Calibrating your oven, or, Why are my cookies burning?

So your recipe said to bake your dish at 350º for 30 minutes but it only been 20 and you smell it burning. Maybe it's been 40 minutes and your cake still resembles pudding. Has this ever happened to you?

While there might be some cases of “user error” (too much of “this”, forgot “that”, etc), you're porably looking at an oven that needs to be calibrated. Calibrated? What-that's what I have an oven thermometer for, isn't it? Well, yes, you should have an oven thermometer and you should check the temperature before you put your dish into the oven. Sometimes we don't though-I know I'm guilty of this fault.

This is why calibrating your oven is crucial to baking success-the actual process of baking, not just mixing the ingredients. If your oven is off by as little as 50º it can wreak havoc on your favorite recipe. While adjusting your oven dial up or down to correct for any discrepancies, it's better to calibrate your oven. It takes about a half hour and it will eliminate one variable if your cookies are spreading or your cake is burned.

I'm sure if my husband (the chemist) was writing this article you would be inundated with details galore about the inner workings of every “whatcha-ma-thingy” in the oven. You would also be able to calibrate a nuclear reactor and know why you shouldn't plumb an acetonitrile line to more than 4000psi. I'm just going to tell you that if you get an oven thermometer from your local grocery or home store (hardware stores have them too), make sure your oven is calibrated at least once a year (more if you bake frequently), you should be just fine.

The short of it is; after heating your oven to a certain temperature (I used 350º), check your oven thermometer and note how far off your oven temperature is, if at all. Shut the oven off and let it cool down while you do the following. Gently pull the oven knob off of the oven. On the back of the knob are (usually) two screws with “+” and “-” (or “H” and “L”) on the back. However it's labeled, loosed the screws and turn the backing in the appropriate direction. My dial “clicks”, others may have hash marks but in either scenario, each click or hash usually represents 10º. So if your oven is off by 50º, you'll want to adjust five clicks toward “-” or “L”. Gently tighten the screws and replace the dial. Replace the knob on the oven and reheat your oven to the same temperature you used the first time. Check again and hopefully you willbe spot on!

Here are step-by-step directions to help you with your gas oven. If you have and electric oven you may have a few extra steps to get your oven calibrated. Also, your owners manual (you still have it, right)should also tell you the proper procedure to calibrate your oven. In any event, if these steps fail to correct your oven temperature problem, it may be time to call a professional.