Candymaking 101: Rock Candy

Rock candy is one of the oldest forms of hard candy, which also happens to be one of the easiest candies to make. It also is one of the candies that takes the longest, taking about seven days to form something edible. That’s probably why it’s not such a popular confection anymore, unless you’re in a second grade science class.

Everyday, I learn so much about erythritol and it’s pros and cons. The cons are focused on so much that the pros are easily missed. Erythritol’s ability to form crystals quickly has always been considered a downside to the sweetener. I can’t tell you how many times my cakes were nice and moist right out of the oven, and then turn to hockey pucks fifteen minutes later. When making rock candy, this quick crystallizing is perfect for cutting the time down from seven days to less than 24 hours! Sign me up for that project!

The basic recipe is a 2:1 solution of erythritol to water, heat on low until solution is clear. You can add coloring and flavoring if you like. I opted for lemon juice for flavor and (a sugar free) strawberry syrup (that I made) for color. It also imparted just a slight touch of pink. Pour your solution into a large jar or bowl, set it in the place you want it to be for awhile (a nice, cool place), and arrange your string or sticks. I’ve always noticed that home recipes always have instructions for string, but when you see it retail, it’s always on a stick! I wanted my rock candy on a stick too, so I devised a sort of “stick rig”: Depending on what container you use, you may have to do something else to keep your sticks in place. Don’t let your stick or string touch the bottom and allow a few inches away from the bottom if you want big crystals on the tip. Once everything is how you want it, DO NOT TOUCH IT for at least twelve hours.

You can leave it for the whole day, you may be able to put it in the fridge for faster crystal formation. I’m always scare to do this because I’m afraid I would forget about it and the setup would turn into one gigantic crystal! After the desired time has passed, loosen the sticks. There is your candy on the stick and in the container. You should have had some nice sized loose crystals form on the bottom.

If you’re not happy with the size of the candy, you can start over by putting all the crystals and remaining liquid back in the pot, and melt again. The candy you see on the top picture measures about 1 1/2 inches. For me, that was big enough.