We had fish fry at church last night, we got there about noon, washed and wrapped 170 potatoes in tin foil and baked them in a confection oven till they were 210 degrees F and then kept them in a cooler, until the fish fry began at 5pm. The insides had all turned brown. What did we do wrong? There must be some way diners keep baked potatoes for a long time without this happening. Any help you can give us would be appreciated.

The potatoes were stored improperly for them to last that long after baking. Also, was there any chance that the potatoes were pierced with a fork to release steam or cut before baking? Those exposed surfaces, especially when wrapped tightly in foil and heated will become oxidized and turn brown or gray. Was it just the area right under the skin that turned brown? If so, they were cooked too long. This can also happen when baking a potato in foil, the skin on the bottom side especially, turns brown from over baking. Next time you might try cooking the potatoes at 185 degrees F as the potato wrapped in foil, will continue to bake.