I have sodium citrate, and I tried a seriouseats / bon appetit / I-can't-fuckin-remember mac and cheese one night.The chemicals in it can help make other cheese much more melty, so its also good for that. Yes, you could also buy sodium citrate or calcium citrate or whatever it is. Or you could just keep American cheese on hand.
Too weird for me. It felt like I made my own boxed mac and cheese.