“Seasoning,” or ripening, a fruitcake involves letting it mature in a cool, dark place for several weeks. While different recipes call for different processes, the basic concept is as follows.
Once the fruitcake is done baking and has cooled, brush the cakes generously with sweet sherry, brandy, rum, port, liqueur or fruit juice; do not use wine. (Note also that using fruit juice will increase the chances of your fruitcake going mouldy.) Wrap each cake in several layers of cheesecloth and then in plastic wrap. Store the cakes in an airtight container in a cool dry place, but not in the refrigerator or freezer.
Check the fruitcakes carefully at least once a week, as rich, moist cakes mould very easily. If you see any mould, throw out the cake. Cutting off the mould and eating the rest of the cake is not a food-safe solution. If the cakes have not moistened in two weeks, apply more liquor or fruit juice.
If the cakes are too moist, remove them from the container and wrapping. Allow them to stand at room temperature for 24 hours, then rewrap and freeze.
Dark cakes usually take four to six weeks to season; light cakes usually take three to four weeks to season. Do not freeze the fruitcake before seasoning. Once they’re seasoned, fruitcakes should be stored in the refrigerator or freezer.
While the process sounds strange, it’s a traditional technique meant to improve the flavour and texture of fruitcake. Unseasoned fruitcake tends to be dry and crumbly, while seasoned fruitcake is easier to slice, and has a more developed taste and texture from the mingling of the fruit with the rest of the ingredients. While you may not always need to season your fruitcake, devotees swear by the process.
Some fruitcake recipes call for seasoning, while others claim to require no seasoning at all. If you try to season a fruitcake that doesn’t call for seasoning, be extra attentive to mould, as there’s a chance the fruitcake wasn’t formulated to survive the room-temperature aging period.