Kitchen Mysteries is a weekly exploration of oddities surrounding cooking and food. They could be recipes that fail when they shouldn’t, conflicting advice from different sources, or just plain weirdness. If it happens in a kitchen, and you’re not sure why, send a tweet to The Food Geek to find out what’s happening.
Rose_w asks via twitter:
You can certainly substitute rice syrup for corn syrup, but I’m not always sure you’d want to. Some of it depends on what you’re using the syrup for.
I discussed syrup a bit in the comments of my article on toffee, and there’s a bunch of other candy-specific information in there. So if you haven’t, please read through that. We have not covered syrup with as in-depth reporting as I might have in a full article, though. Let us plunge in all the way and learn the ins-and-outs of syrup.
Candy is a struggle of material science. What we’re trying to do with it is to create a specific texture and hardness of material from essentially the same set of ingredients. Most of the heavy lifters are sugar, water, butter, cream, acids, and/or corn syrup.
Corn syrup’s main goal is to keep the sugar that’s dissolved in the water from crystalizing. The way it pulls this off is by being weird with how it stores its sugars. Table sugar is composed of sucrose, a disaccharide, which means you have to simpler sugar molecules, fructose and glucose, stuck together. So given nothing else, table sugar dissolved in water will be pretty much sucrose.
Corn syrup, on the other hand, is mostly glucose. The reason it’s so, well, syrupy is because it’s not just single molecules of glucose all hanging out by themselves, but chains of glucose. Sometimes they’re short chains, sometimes they’re long chains, but because they’re all jumbled, it slows everything down.
The reason why you put the corn syrup into the candy is because, when you just have single sugar molecules by themselves, then the sugar molecules want to bunch together to make crystals. It’s really keen and useful for certain kinds of candies, but not as useful for others. Corn syrup gets in-between the sucrose molecules so, while they would normally join hands together, they instead bump into the glucose chain which they can’t join in on. Therefore crystal formation is hindered significantly.
Rice syrup has very little sucrose in it, like corn syrup. However, it also doesn’t have a lot of glucose. Instead, it’s mostly maltose and complex sugar molecules. These should interfere with the crystal formation in a similar way to the glucose chains, because they won’t bond with the sucrose. Going from that perspective, it should work fine.
On the other hand, rice syrup is generally much less refined than corn syrup, and has a distinctive flavor and color. Using this in a candy will likely change the flavor. The change could be good or it could be less than ideal, so you’ll likely want to try it with a recipe to see what it does to the flavor.
It’s worth noting that rice syrup is made through a fermentation process which requires the use of certain enzymes. These enzymes may have been grown on wheat grains, which means that the rice syrup may contain gluten. If gluten is a concern for your candy connoisseurs, check the label to ensure a gluten-free additive. I mention because candy is not where you’d expect to find gluten, so it would be easy to make an inadvertent mistake with it.