Science helps craft the perfect mac and cheese

Associated Press

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.

In solid form, cheese is a stable emulsion. The tiny droplets of dairy fat are suspended in water and held in place by a net of interlinked proteins. When cheese melts, however, that net breaks apart, and the oil and water tend to go their separate ways. Sodium citrate can form attachments to both fat and water molecules, so it holds everything together. The end result is a perfectly smooth, homogeneous sauce. The sauce even can be cut into processed cheese-like slices once it cools.

When making cheese sauce, we add 4 grams of sodium citrate for every 100 grams of finely grated cheese and 93 grams of water or milk. To make cheese slices, we reduce the amount of water to about 30 grams (cold wheat beer works very well, too), pour the melted mixture into a sheet pan, and let it solidify in the refrigerator for about two hours before cutting it into pieces, which then can be wrapped in plastic and frozen.

Because this method of stabilizing melted cheese bypasses all of the flour, butter and milk used in Mornay sauce, the resulting cheese sauce is much richer; a little goes a long way. But the sauce keeps well in the refrigerator and reheats nicely in the microwave, so save any extra and use it to top vegetables, nachos or pasta.

For our Mac and Cheese recipe, click here.

Photo credit: Melissa Lehuta / Modernist Cuisine, LLC

How to Scale a Recipe

The Mac and Cheese recipe makes five servings, but you’re throwing a dinner party for nine people. You’re in luck: We’ve made it easy to scale our recipes up to greater yields (or down if you have fewer mouths to feed) by using baker’s percentages. Just follow these simple steps.


  1. Look in the scaling column of the recipe, and find the ingredient having a scaling value of 100%. Note the weight given. The 100% ingredient is usually the one that has the biggest effect on the yield of the recipe.
    Example: The 100% ingredient in the Mac and Cheese recipe above is white cheddar cheese.
  2. Calculate the scaling factor by dividing the number of servings (or grams) you want to make by the recipe yield.
    Example: This recipe yields five servings. If you are making nine servings, the scaling factor is 9 ÷ 5 = 1.8. (You can use the weight of the yield rather than the servings to calculate the scaling factor: If you want to make 1,100 grams of mac and cheese from a recipe that yields 800 g as written, the scaling factor is 1,100 ÷ 800 = 1.4.)
  3. Calculate the scaled 100% value for the recipe by multiplying the weight of the 100% ingredient by the scaling factor from step 2.
    Example: This five-serving recipe calls for 285 g of white cheddar, which is the 100% ingredient. To make nine servings, you will thus need 285 g x 1.8 = 513.0 g of white cheddar cheese. The scaled 100% value for this recipe is 513.0.
  4. Calculate the scaled weight for every other ingredient in the recipe by multiplying its scaling percentage by the scaled 100% value from above. You can ignore the weights and volumes given in the recipe—just use the scaling percentages.
    Example: The scaling percentage given for dry macaroni is 84%. Multiplying this by the scaled 100% from step 3, you find that 0.84 x 513.0 = 430.9. Similarly, you need 0.93 x 513.0 = 477.1 g of water or milk and 0.04 x 513.0 = 20.5 g of sodium citrate.

Because volume measurements are often rounded to the nearest spoon or cup, you should not multiply or divide volumes when scaling a recipe up or down. Instead, scale the weights as described above, and then weigh the ingredients on a digital scale.

Adapted from Modernist Cuisine at Home