Throughout history farmers have used fermentation to preserve fruit harvests. The Probstfield family of Oakport could not possibly eat all the apples grown in their orchards before the fruit rotted, so they turned their apples into alcoholic cider which could be enjoyed throughout the year. The juice would naturally start to ferment (turn alcoholic) after just a day or two! As long as the family did not sell it or move it off their property, making cider or other fruit wines did not violate Prohibition laws.
Interesting! I did not know that home production was allowed during prohibition.