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Black Spots after Piercing Potatoes

Q:

We held a large banquet last night. We scrubbed and pierced the potatoes (some of them pierced with a fork), wrapped them in foil and baked them the next day.  We were horrified when we cut the "fork" pierce potatoes to find them black where they were pierce with the fork.   Is there any way to prevent that from happening? That didn't happen on the knife pierced ones.

A:

The black spots are where the potato oxidized when exposed to air. Sometimes this is exaggerated by the metal of the fork or knife, especially older ones where the material had some iron in it.

Lesson learned; don’t pierce the potatoes too far in advance.

One trick once pierced, is to dip the potato in a solution of one gallon of water to 1 tablespoon of concentrated lemon juice or white wine vinegar, something acidic to help the potato from darkening. Most times (unless preparing potatoes for baking in the microwave) you can skip the piercing with a fork. Lots of restaurants don’t do the extra step and rarely have a potato burst while cooking.