My dad grew up in rural Iowa almost 100 years ago. He didn't have electricity or running water and no air conditioning or refrigeration. Ice cream was a rare treat that could be bought on a trip into town or perhaps made in the winter.

Ice was available in the winter, and also in the summer because large blocks of ice would be cut from frozen ponds during the winter and stored in ice houses. These ice houses here partially underground structures, like a barn but buried up to their roof underground.

I saw an ice house that was no longer in use as a young child, and as I recall (I would have been perhaps seven years old) I was told that it was filled with sawdust, hay, or straw to insulate the blocks of ice.

Today, the reported underground temperature in Iowa at 40 inches is about 65°F (18°C) and deeper it can reaches a steady state temperature of 45 to 50°F (7 to 13 °C). I don't know how late into summer those ice blocks survived.

I remember growing up that my father greatly enjoyed making homemade ice cream; I suppose it connected him to the happy times of his quite difficult childhood.