How To Skim Off the Scum and Fat from Soups and Stocks (灰汁取り)

In Japanese cooking, skimming off the scum and fat that accumulates on the surface of broths and stock is very important to create a nice and clean soup or stew. It’s an important technique used in the culinary arts by professional chefs and home cooks alike.

Yes, I know it is extra work! However, it’s the key to a refined flavor and clear liquid. Soup skimming is worth the effort when making hot pots, stews, and all types of soup like chicken noodle soup, pho, and beef bourguignon.

What is the Foamy Scum on Stock?

When liquids like chicken stock or bone broth are just about to boil, the proteins in the animal products start to congeal. This creates foam that rises to the surface. It can appear when boiling meat-based liquids like pork bones, beef knuckles or marrow bones, and chicken carcasses.

It’s usually white, gray, or brown in color. It’s crucial to remove the foam as quickly as possible before it boils and mixes into the soup or stock. 

How To Skim Off the Debris and Scum 

Here’s a summary of how I do it; see below for step-by-step photos and instructions!

1. Prepare a liquid measuring cup filled with water. You’ll also need a fine-mesh skimmer. You could use a ladle or slotted spoon, but I prefer a mesh strainer of some kind.
2. Just before the liquid in your stockpot begins to simmer and boil, look for the scum to form. When you see it floating at the top of the soup, quickly scoop it off.
3. Rinse the fine-mesh sieve in the water. Repeat until you’ve removed all the debris from your soup.

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