When I made it the other day with equal amounts of isomalt and corn syrup, it came out yellowish. I thought it was because the corn syrup contained vanilla, but now Iâm not so sure. A cake friend of mine said to use isomalt and water, 4:1 ratio. So I tried that and it still came out yellowish. We think it is because I am cooking it in the microwave and it is getting too hot. Iâm going to try it on the stove with the candy thermometer sitting in it.