Why do uncooked frostings that contain milk not need to be refrigerated?
I have seen (and used) recipes for icing and glaze that use uncooked milk in them, yet they do not need to be refrigerated. (For example, one with powdered sugar, milk, vanilla and butter or shortening.) If I just left out a cup of milk, it would spoil. Is the sugar chemically changing the milk in some way so it does not spoil?
Best Answer
Microbes need available water to grow, and sugar reduces the availability of water to them. In addition, spread as a thin layer on cake, water evaporates (further reducing water availability).
You can find out more about factors influencing microbial growth in the FDA's Bad Bug Book.
As the book notes, generally, you can only know from experiment if a particular recipe is safe, and also that often they're just slowed not stopped. So it'd probably be prudent to minimize the amount of time you store your icing/glaze.
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Quick Answer about "Why do uncooked frostings that contain milk not need to be refrigerated?"
It is called crenation. Basically, the sugar acts as a super concentrated solution and pulls the fluid from the milk. When it does this, it also pulls fluid from any bacteria which may cause spoilage. Essentially, killing the bacteria through osmosis.Does frosting with milk have to be refrigerated?
Always refrigerate any cake with a frosting that contains eggs or egg whites, or one that has whipped-cream frosting or any type of filling \u2014 be it whipped cream, custard, fruit or mousse. You won't hurt a cake by refrigerating it, but the cold does dry it out.Does buttercream frosting with milk need to be refrigerated?
Nope! Buttercream that utilizes heavy cream (or milk or cream) does not need to be refrigerated right away. This is because there is such a small amount that is used. The large amount of sugar will render these ingredients stable for a few days on the counter.Is frosting still good if not refrigerated?
That is a great question! Your cupcakes will not need to be frosted if you are serving them the next day. Our general rule of thumb is: if you are using them within 2 days, store cakes and cupcakes loosely covered, outside the refrigerator. If using from 2 to 7 days, store them in the refrigerator, tightly covered.Does icing with evaporated milk need to be refrigerated?
Do not refrigerate the frosting, even if you don't plan to use it for a few days. Store in an airtight container at room temperature for up to 3 days.Does Buttercream Frosting Need to Be Refrigerated?
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Answer 2
It is called crenation. Basically, the sugar acts as a super concentrated solution and pulls the fluid from the milk. When it does this, it also pulls fluid from any bacteria which may cause spoilage. Essentially, killing the bacteria through osmosis.
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