HAs anything else been baking inconsistently? You may try getting an oven thermometer and turning the oven on and checking it every 10 min for an hour or so to see if it is maintaining the temp.

I don't think the flour would make that big a difference.

Use an instant read thermometer to check and make sure the bread hits the right temperature. Does this dough contain oil/fats or added sweeteners? An enriched dough should be at least about 195, lean doughs need to be around 200+ in the center.

Your post is a bit unclear.  Did the bread stop baking completely when you used the new hand milled flour?  If so that could most definitely affect your baking.  Other than that I would double check the temperature in your oven and use an instant read thermometer to make certain that the center of the baked loaf is at 200 degrees Fahrenheit.

Jeff

Thank you everyone, on the instant read thermometer. I never thought of that!

Hi, another two cents.

I like the Idea of owning an instant read thrmometer, I enjoy using mine as a  doneness test. But I think an oven thermometer is a must investment. It isn't likely your oven is 25 degrees off, but then, how would you know? The thermostat can be recalibrated easily, to agree with the oven thermometer. If it is the new flour, it will be nice to know your oven temp is right on the money, and can be eliminated as the cause of the problem. Clazar123, offers a good idea, checking the oven temp. every 10 minutes for an hour. The oven thermometer is inexpensive, and comes with instructions. If your oven has a window, try to position the thermometer so it can be viewed without opening the oven door. That way your oven won't always be recycling needlessly.  Ray