Don't add powdered starch to hot water. It will clump. Add it to a small amount of cold water and then add that to the hot pasta water. (And the starch you want is amylopectin. Waxy potato starch will work better than corn starch [1].)
[1] https://www.researchgate.net/figure/Amylose-and-amylopectin-...
Don't add powdered starch to hot water. It will clump. Add it to a small amount of cold water and then add that to the hot pasta water. (And the starch you want is amylopectin. Waxy potato starch will work better than corn starch [1].)
[1] https://www.researchgate.net/figure/Amylose-and-amylopectin-...