Baking soda and lemon juice react to create a bubbly compound called sodium citrate that serves as an emulsifier and binding agent when added to cheese.
The sodium citrate breaks down the calcium in cheese’s rigid network of casein proteins, releasing the proteins to create a more uniform mixture and a smooth sauce.
Simply combine two and a half teaspoons of baking soda with two teaspoons of lemon juice in water in a pot. Once the bubbles abate, you can begin building your cheese sauce.
Although the lemon sounds like it would add a tartness to the sauce, the baking soda tames its tang, leaving you with a deliciously cheesy and velvety dip.