The mystery of the moister cake

One of my twitter friends posted what was, to him, a disturbing tale of a cake transformed. In 140 characters or less, here was the conundrum:

From Twitter user Steve. Me: 'This (day-old leftover) cake is really moist!' Her: 'Wow. It was bone-dry yesterday.' #ulp

After eating the cake, his mind was alight with frightening tales of adulterated coffee in offices and strange and weird ways that the cake could have become more moist over the course of a day. None of those possibilities made him feel particularly good about the thus-eaten cake.

However, I know a food secret, and it's this: sugar loves water. Loves it. Sugar has a water tattoo on its shoulder, and when they're not dating, it hangs out creepily next to water's car when water is at work, writing little messages in the windows that water won't see until the dew hits the next day.

Most substances, when they sit out in the open air, become dryer as time goes on. Bread goes stale, food sticks to the bottom of a bowl, dogs no longer have to shake the water off onto the entire living room, etc.

With sugar, though, you've seen how it starts clumping together given half a chance. You let the sugar sit in the jar too long, and you'll have to break it apart. That's because sugar is hygroscopic, which, as I mentioned, means it loves water, especially water that is hanging around in the air.

Cakes are sweet, what with all the sugar in them. So even a cake fresh from the oven that is dry has a chance to moisten up if there's any humidity at all. Generally, a cake is better the second day than the first for just this reason.

Steve felt much better after I told him about that, and I performed another public service, so it was a good day all round.