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A funny thing happens when you add cornstarch to a liquid and heat up the mixture: It gets really, really thick, or viscous. That thickening process is called starch gelatinization, and it occurs almost anytime you heat starch in the presence of water. For anyone who loves puddings, pies, gravies, and creamy soups, cornstarch gel is an essential ingredient because it improves texture.
But cornstarch gel isn’t just good for cooking—it also makes a great base for homemade paint. Cornstarch gel is non-toxic, it gets nice and thick, and it is easy to clean from paint brushes and squeeze bottles. But cornstarch gel is pretty clear, which means that if you paint it onto something like a canvas or T shirt, it isn’t that visible. To make cornstarch gel into a good paint, you have to add pigment to make it opaque, or hard to see through.
So how can we make cornstarch gel opaque for painting?
To find out, we will first need to gelatinize some cornstarch, and then get mixing. Here’s what to do: