If Jerry Seinfeld were doing a stand-up routine on fruitcake (and I’m certain he has at some point), it would surely begin: so what is that funky colored fruit all about?
Earlier I wrote that fruitcake makers of old used dried fruit, and indeed they did. The trouble with dried fruit, though, is that once you re-hydrate it, it can once again become fair game for microbial n’er-do-wells. In the absence of liberal dosings of alcohol, that can severely limit the keeping ability of the cake. This is part of the reason bakers eventually migrated over to candied fruits, which are not only much sweeter and better looking, they keep far, far longer.
Humans have been preserving fruit in sugary substances for millennia. The ancients preserved whole fruits in honey, since not only is honey an extremely dense sugar, it also contains acid, which helps shut down the browning and ripening enzymes in the fruit’s flesh. But while preserving in honey can be a very effective technique, honey’s relative scarcity made it impractical for large-scale preserving. Likewise with sapa, a kind of intensely boiled-down grape juice that the Romans used for the same purpose.
Thus large-scale fruit candying had to wait for the arrival of crystallized cane sugar, which came on the European scene around 1500 (the earliest written fruit-candying recipes date to that time). The process is as straightforward as it is time-consuming. Ripe fruit is first boiled or simmered to soften it up a bit (the heat also helps destroy those pesky ripening enzymes I just spoke about), then immersed in a thin sugar syrup for a day, after which the fruit is drained and immersed in a slightly stronger sugar syrup for a day, after which it is drained and immersed in a still stronger syrup and so on. Why is it done this way? Because soaking fruit in an intense sugar solution right off the bat causes it to pucker up like a prune. The longer and slower the process, the more tender and delicate the end product. Some artisanal candied fruit makers (mostly European) still employ this painstaking method. It can take months, but the finished fruits look like they were just picked off the tree.
The vast majority of candied fruit today is of course produced by industrial means. Sliced or cut pieces of prepared fruit are tumbled in vats as they’re sprayed with a sugar and/or corn syrup solution. The process still takes days, but it’s considerably quicker than the old-school method. Afterward they’re left to dry, then either given a final coating of a thick syrup (for a finish known as glacé), or given another tumble in sugar, in which case they go by the name of crystallized fruit.