The process commences in late spring when the first crops of fruit come into season, usually strawberries. The ripe, unblemished berries are macerated with half their volume in sugar, added to a stoneware crock, and submerged in dark rum or brandy. The process continues throughout the summer as fruit comes into season, culminating in the autumn with apples and pears. After the last of the fruit has been added to the pot, the rumtopf sits idly by for a month or two and then is ladled up in December.
As a way of preserving summer fruits, rumtopf offers something more than making jam. "Putting up fruit in alcohol preserves a different kind of character to the fruit. You pull a different range of flavors. You have this complex thing going on where, if you do it right, the fruit lends something to the liquor and the liquor lends something to the fruit. It makes it a very adult thing," explains Francis Schott of Catherine Lombardi and Stage Left restaurants in New Brunswick, New Jersey, who preserves Jersey-fresh fruits in spirits, scented with spices, each summer for use in the restaurants' bars.
Another benefit of putting up fruit in liquor is that it is less risky than canning. Alcohol is an effective preservative, and together with the high acidity of the fruit and the added sugar, it creates conditions inhospitable to unwanted microbes. In addition, the rumtopf is an aerobic environment, since there isn't a perfect seal on the crock, which means the potential for botulism is minimized. You will need, however, to cover the pot (a plate will do if the crock has no lid), to limit evaporation and maintain a clean environment. And the fruit must be weighted down with a small plate so it stays submerged and won't spoil.
As with homemade jams, the rum-based cordial is much sweeter than the fruit itself. It might be tempting to cut back on the sugar. Don't! Sugar plays a vital role, not only in the preservation process but also in the development of flavor. Schott learned from experience that the sugar is necessary. Without the presence of sugar, alcohol would draw all the flavor from the fruit, rendering it flavorless mush. The goal is to have both a fruity cordial and boozy fruit.
It's tempting to choose an economical spirit to keep costs down. Again, don't! Just as you shouldn't add a piece of fruit to the rumpot that you wouldn't eat out of hand, don't pour a rum into the crock that you wouldn't drink straight. You don't need something high-end, but select something decent and at least 80 proof, which prevents the fruit from fermenting. Choose an organic rum, such as Papagayo or Crusoe brands, which are made from organic sugarcane.
Rumtopf is not an inexpensive project, due to the quantity of alcohol and fresh fruit, but you can put both to luxurious use as a festive party centerpiece. And the taste of summer fruits in spirits in wintertime is simply priceless.
Basic Recipe for Rumtopf
The following fills a 2-gallon crock. You can certainly halve or quarter this recipe and use a smaller jar. Select whichever fruits are in season where you live, but note that melons don't work well.
3 cups strawberries, hulled
2 cups each, 8-14 different ripe and unblemished fruits*
9 1/2 - 15 1/2 cups sugar (1 cup for every 2 cups of fruit)
2 liters organic dark rum or brandy, at least 80 proof
*Suggestions: apples (cored and sliced); apricots (pitted and sliced); beach plums (pitted); blackberries; blueberries (pierced); cherries (pitted); currants, red and black (pierced); figs (sliced); gooseberries; nectarines (pitted and sliced); peaches (pitted and sliced); pears (cored and sliced); plums (pitted and sliced); raspberries
1. When a crop of fruit comes into season, wash and prepare the fruit as directed. Put the fruit in a bowl and toss gently with half its volume in sugar. Let the fruit macerate at room temperature for 30 minutes or even overnight.
2. Add the fruit with its juices and sugar to the crock. Pour enough rum or brandy into the crock to cover the fruit. Place a small plate atop the fruit to keep it submerged. Cover the crock with its lid or a plate and keep in a cool place.
3. When the next fruit comes into season, follow the same process, making sure that there's enough rum or brandy to cover all the fruit and that the fruit stays submerged.
4. After the last fruits come into season, let the rumtopf sit for a month or two. Then drink the cordial and eat the fruit.
Originally published in Organic Gardening Magazine, Oct/Nov 2013