Have you opened a carton of yogurt or sour cream and found a watery layer that separated out? Some call it “weeping,” but it is technically called syneresis. Simply put, the gel lets go of some of the liquid. Why does this happen?
Foods like yogurt, sour cream, pudding, even ketchup are gels. During storage, the structure tends to contract and looses its power to hold in water. Some gels are looser when hot, but tighten up when cooled. This can also result in water loss. Gelling ingredients, such as xanthan gum, can help control syneresis, but can also result in a stiff, rubbery final product. Ice crystals on ice cream is another form of syneresis.
So don’t cry over syneresis! Shake the ketchup bottle, stir the sour cream and you’ll never know it wept!
Source: Cook’s Illustrated, February 2017
