Follow This Simple Tip For Clearer Stock
Want chicken, beef, or pork stock so clear you can see your reflection in it? There are techniques for that. To that end, if you've ever made chicken stock, you've probably noticed the scum that rises to the surface. This scum, despite its name, is not gross or harmful; it's simply proteins from the animal bones that have semi-solidified in the water and floated upward (via Fine Cooking). The only downside of scum is that if not removed properly, it will make a clear stock cloudy.
Most stock recipes, such as Alton Brown's, say to gently simmer the liquid — as boiling it would cause the proteins to emulsify into the liquid rather than rise to the top, Cook's Illustrated explains — so you can easily remove the scum with a strainer every 15 minutes during the first couple of hours of cooking. However, while effective, this still might not result in perfectly clear stock.
Another method is to cook raw egg whites in the hot stock so they capture impurities and form a removable "raft." The problem with this? It captures flavor, too, says The Guardian. For the purest stock, take just one extra step: blanching.
How blanching bones creates clearer stock
Blanching, or briefly cooking food in boiling water, is usually done to pre-cook vegetables, Kitchn explains, but this technique can also be applied when making stock. Simply blanch your bones in a big pot of water, drain, and add to a fresh pot of cold water to be simmered along with the vegetables and aromatics.
Blanching is common in Chinese stock-making, according to Kitchn, and helps the proteins from bones "clump together" more effectively so the scum is easier to remove. The method is favored by chef Brandon Jew of the acclaimed Mister Jiu's restaurant in San Francisco. For his oxtail soup, he blanches the oxtails for one minute before cooking them in chicken stock (made with bones that were blanched for 15 seconds before simmering).
The blanching method certainly requires additional effort, but Kitchn says it results in stock that is "beautifully clear with a pure, clean flavor, and 100 percent worth the extra work." After blanching the bones, continue making the stock as normal, occasionally skimming any rising scum. For best results, cut your vegetables into two-inch pieces (as smaller ones will "dissolve" and cloud the stock, according to Woks of Life) and strain the final mixture through cheesecloth or a coffee filter.