What’s That Foam on Top of My Chicken Broth?

Making your own stock or broth at home is a warm, comforting process that’s also a smart way to use up kitchen scraps that might otherwise be wasted. Plus, while there’s ongoing debate over the health benefits, a homemade stock—like all things prepared with care—always brings richer, more flavorful results than what you’d get from a store-bought box or can.

If you’ve ever tried making stock, especially if you’ve dabbled in the popular bone broth craze, you’ve likely noticed a strange layer forming on top of the pot. It’s hard to miss, especially when the house is filled with the delicious scent of simmering broth.

So, What’s This Foamy Layer?

The foamy, grayish-greenish substance is commonly known as 'soup scum,' or more politely, 'impurities.' While the name may sound informal, the science behind this layer forming in your pot is quite real.

Can I Eat the Foam?

The short answer is yes. The foam that forms on top of chicken broth or stock is harmless—it’s just not very appetizing. While it may look unappealing (and possibly feel a little odd), it won’t affect the flavor, so whether you remove it or not is purely a matter of personal preference.

If you’re aiming for a clear, pristine broth or a well-reduced consommé, you’ll definitely want to skim off that foam.

How to Get Rid of Soup Scum

The best way to deal with that stubborn 'soup scum' is to skim it off. Using a fine-mesh strainer or spider strainer, gently run it over the surface of the liquid, just like you would scoop leaves from a pool. Be prepared for this to take some time—expect to spend about 10-20 minutes. After the stock cools, strain it through muslin or cheesecloth for a cleaner finish, though don't rely on this step to completely do the job.

If you begin making your stock with cold water and gradually bring it to a boil, the slow rise in temperature will make it easier to see and remove the coagulated proteins.

Typically, most of the scum forms and rises to the surface within the first 10 minutes of boiling. Once that’s cleared away, you can simply relax and let the stock work its magic.

Here’s a little pro tip: once your broth reaches a simmer, stir in some beaten egg whites. The proteins in the egg whites will bind with the coagulated bits, creating a visible mass that's easy to skim off. Just be aware that if you have small ingredients like vegetables or beans, they may get caught in the egg white mixture, so adjust accordingly.

Do You Really Have to Deal with Scum?

There are ways to minimize or avoid skimming your broth altogether. One method is to pre-boil the meat or bones and rinse them before starting your stock. While this will slightly reduce the flavor, it will save you from having to skim.

Another option is to roast the stock bones in the oven before making the broth. However, either method may end up being just as much, if not more, work than simply standing at the stove and skimming the scum.

Alternatively, you could use a pressure cooker. While your kitchen won’t be filled with the comforting scent of simmering chicken and vegetables, the impurities will settle at the bottom of the pot, resulting in a much clearer broth.

To Skim or Not to Skim

In the end, whether or not you skim the scum from your broth is entirely up to you. If it doesn’t bother you visually and the broth is just going to be used as a base for other dishes, you can leave it be and save yourself the extra effort. However, if you're making a soup and want a cleaner, more appetizing presentation, it’s worth removing it.

Either way – enjoy your slurping!