Until recently, I’d never given canned milk much thought. But last summer, I was following a new recipe for potato salad that called for evaporated milk, and I mistakenly used condensed milk. Having ruined the salad, I decided it was time to figure out what was what.
Both evaporated and condensed milk begin as fresh milk. The milk undergoes a vacuum process that evaporates over half the volume of water and concentrates the nutritive part of the milk. Evaporated milk is then poured into cans that are heatsterilized to prevent spoilage. The ultrahigh temperatures of sterilization cause the milk sugars to caramelize and give evaporated milk its characteristic cooked taste. In the end, evaporated milk has the consistency of light cream and a tint that ranges from ivory to pale amber.
Condensed milk is basically evaporated milk with a lot of sugar added (up to 2-1/3-cups per 14-oz. can) before it’s canned. The result is a thick, gooey, and intensely sweet product. Since large amounts of sugar prevent bacterial growth, condensed milk doesn’t need to be heat-sterilized and has a less caramelized flavor than evaporated milk.
Despite their similar packaging and nomenclature, evaporated and condensed milk are not interchangeable. Evaporated milk can be reconstituted with an equal volume of water and used to replace fresh milk in most recipes.
According to food scientist Shirley Corriher, undiluted evaporated milk is good in sweet bread doughs because of its high concentration of lactose, or milk sugars. Apparently yeast don’t like lactose, which means that a greater amount of residual sugars (unconverted by yeast activity) remains in the final bread, and the loaf is sweeter.
Due to its high sugar content, the primary use for condensed milk is in sweets. Bakers find it especially useful in candy and fudge since the sugar has already been boiled down into a syrup, meaning fewer problems with crystallization. Condensed milk is also often used to give some bar cookies their characteristically gooey consistency. When beaten with an acid, such as lemon juice, condensed milk develops the consistency of soft cream cheese, and this mixture is sometimes used for making cheesecakes and pies.