Distilled alcohol is antimicrobial and stable, so preserving fruit in alcohol long-term is a good option. The classic German rumtopf recipe below (classically made in a rumtopf crock, but you can use any jar) preserves fruit in sugar and rum. Start a jar in spring, add fruit as it comes into season, and it will be ready by December (but even richer if you let it brew another year).
You can use any fruit — from your garden, or from a farmers market sale at the end of the season. Try preserving apricots, blackberries, cherries, grapes, peaches, pears, plums, raspberries, or strawberries. Pineapple tends to overwhelm the flavor of other fruits. Feel free to experiment with combinations or stick with a single fruit.
How to Make Rumtopf
• Seasonal fruit
• 1 cup sugar per pound of fruit
• 108-proof rum
1. Start with a 1-gallon, wide-mouth glass canning jar, or with a 1- to 3-gallon classic rumtopf crock. Add fruit, prepared as you prefer, and sprinkle a cup of sugar over each pound of fruit. Pour in rum to cover the fruit.
2. Keep the fruit submerged in the rum. You can do this by putting wax paper directly on the surface of the liquid, or, if the container is wide enough, by weighting the fruit down. A plate with a closed jar of water on top (as long as it will fit inside the container) will work well.
3. Keep adding different fruits as they come into season, plus additional rum and sugar each time.
4. After the rumtopf jar is full, cover it and store it away from direct light. Age it for a minimum of 3 months before serving. Before that, the flavor may be harsh, but as it ages it will become deliciously mellow.
5. After the rumtopf has aged, lift out the boozy fruit with a slotted spoon and use it to top ice cream, cakes, custards, puddings, and other desserts. After the fruit is gone, serve the fruit-infused rum as a digestif or in cocktails.
For much more on simple food preservation techniques that require low or no energy, browse the tips in Off-Grid Food Preservation Methods.