You sure can. A standard ice cube from a tray is about one fluid ounce, (30 ml) (two U.S. tablespoons). You can pour leftover syrup into a tray, freeze until solid, and then transfer to an airtight container like a zip-top freezer bag. That's an easy way to keep what's essentially measured doses of syrup on hand. You can defrost in the fridge overnight, at room temperature, or with a quick spin in the microwave.u003cbr/u003e