Imagine your favorite cheese: perhaps an aged, sharp cheddar, or maybe a blue Gorgonzola or a gentle Monterey Jack. Wouldn't it be wonderful to use those really good cheeses you love on nachos or as a sauce on macaroni or steamed vegetables?
But if you have ever tried melting high-quality cheeses, you've experienced the problem: the cheese separates into a greasy oil slick that no amount of stirring will restore.
One traditional workaround is to make a Mornay sauce, which combines the cheese with a cooked mixture of flour, butter and milk. But a Mornay sauce can end up tasting as much of cooked flour as it does of cheese. The starch in the flour actually masks some of the flavors in the cheese, so the sauce loses its vibrancy.
A clever Canadian-born cheesemaker in Chicago discovered a much better solution around 1912. His name may ring a bell — James L. Kraft.
Kraft found that adding a small amount of sodium phosphate to the cheese as it melted kept it from turning into a clumpy mess of cheese solids swimming in a pool of oil. Kraft patented his invention and used it to make canned, shelf-stable cheese. He sold millions of pounds of the stuff to the American military during World War I. The technique ultimately led to the creation of Velveeta and a whole universe of processed cheese products.
You can apply the very same chemistry, however, to achieve much higher culinary purposes. The chefs in our research kitchen have made mac and cheese with an intense goat gouda and cheddar sauce, for example, and build gourmet grilled cheese sandwiches using cheese slices that melt like the processed stuff, but are made from feta or Stilton.
In place of sodium phosphate, we use sodium citrate, which is easier to find in grocery stores or online. Like sodium phosphate, sodium citrate is an emulsifying salt that helps tie together the two immiscible components of cheese: oil and water.