Ovens  
All ovens preheat differently. If your oven has a digital control with a preheat tone,it may not be at the correct temperature when it beeps. Twenty to thirty minutes is a good preheat time for most ovens. You may want to check your oven temp with a oven thermometer. Place your thermometer in the center of your oven. Let your oven preheat for thirty minutes then check your temp. Most digital oven can be adjusted + or - thirty five degrees. Refer to your owners manual on how to change your temp. Adjust if necessary and let oven cycle one more time and recheck.

 

I hope this tip was helpful for you.

                                                                          Gary