Hello Chloe. Preparing a big batch of mac and cheese to freeze is a wonderful strategy for quick weeknight dinners, but freezing can sometimes cause cheese sauces to break or turn grainy if you do not select the right cheeses and techniques.
To achieve both a deep, rich flavor and a silky, smooth melt, I recommend using a blend of sharp cheddar and Gruyere. Sharp cheddar provides that classic, bold mac and cheese punch, while Gruyere offers a rich, nutty depth and melts into a beautifully smooth liquid without separating. A fifty-fifty blend of the two creates the ideal balance. If Gruyere is unavailable, Monterey Jack or a mild Gouda are fantastic alternatives for smooth melting.
The single most critical factor for a smooth texture is to buy block cheese and shred it yourself. Pre-packaged shredded cheeses are coated in anti-caking agents like cellulose and potato starch. These coatings prevent the cheese from melting uniformly and often result in a grainy, gritty texture, which becomes even more noticeable after freezing and reheating.
Finally, for freezing specifically, emulsion stability is essential. I suggest making a classic Mornay sauce foundation using a butter and flour roux, or substituting part of the milk with evaporated milk. A helpful trick is to add just one or two slices of deli-quality processed American cheese to your sauce. The emulsifying salts in American cheese bind the fat and liquid together, ensuring your dish reheats from frozen with the exact same creamy consistency as the day you made it.