What's a good target internal temperature for fruit pies, for the fruit to be cooked? Most recommendations seem to be to have the filling bubbling, plus 5 minutes, but is there a more precise way to know when the pie is done?
I think there are three variables in fruit pies:
- Amount of water
- Amount of sugar
- Amount of starch or pectin
Pectin will be activated by sugar and acid at below boiling temperatures, so seeing bubbling should indicate that the thickening caused by pectin has happened well beforehand. Therefore, the mix of water and sugar will modulate the boiling point to indicate done-ness. Since pie filling is less sweet than jam, take a look at this:
So 220F seems like a high upper bound.
Therefore, I would expect a done fruit pie to be slightly above boiling, so maybe 215 F or 102 C?
Let me know how it goes!