in other news.............. I think I remember a short discussion regarding melting cheese
https://www.seriouseats.com/2015/08/the-science-of-melting-cheese.html?utm_medium=email&utm_campaign=Features_20210128_Thursday_MeltedCheeseScience&utm_content=Features_20210128_Thursday_MeltedCheeseScience+CID_f043f2e639f50e22d8c819d6607f5fe6&utm_source=Email%20campaign&utm_term=Get%20the%20full%20storyOne of the most common ways to help cheese melt smoothly is to add starch: this is a process that works in sauces like mornay, or nacho cheese sauce. Starches and other thickeners will physically impede fat molecules from joining up into larger droplets, as well as making the water phase of the cheese more viscous. All of this helps to prevent fat from coalescing and breaking out.
Adding acid, like the tartaric acid you'll find in a tart white wine, can also help prevent the cheese's casein proteins from clumping together and turning stringy, like in a classic fondue (our recipe uses a touch of starch for further protection from breaking).
But when even that's not enough, it's time for the big guns: more liquid. This is where Kenji's genius steaming technique comes into play. Steaming a cheese doesn't just heat it more evenly and gently than, say, a toaster oven, but it reintroduces water that's otherwise lost in more traditional heating methods. You can even go the whole nine yards and stir in a combination of milk or cream and starch like Gold Medal Wondra Flour—this method's perfect for topping burgers or filling your next grilled cheese. Check out the full story or go one step farther and learn how to make American-style cheese slices from scratch out of nearly any cheese! (Hint: it involves a food processor, gelatin, and a whole lot of goo).
The Super Melters: Process Cheese
Process cheeses, including "American" cheese, are cheese products designed to be extremely meltable and nearly impossible to break. This is accomplished by starting with real cheese (usually a young cheddar-style), and blending it with extra milk (for the added water), extra milk protein micelles (for the strong protein structure), and some form of chemical salt that helps prevent proteins from tightening. Because American-style cheeses have so much excess liquid added to them, they have extremely low melting points, making for extra-gooey grilled cheese sandwiches or cheeseburgers. This meltability, of course, comes at the cost of less intense flavor.