Everyone wants that perfect gravy come Thanksgiving but have you ever found yourself struggling to get it to the right consistency? It’s all in how you thicken your sauce. The same could be said about soups and stews.
In general, there are four thickening techniques you should have under your belt. Here's an overview of how to thicken a soup or gravy and which methods work best:
How To Thicken Soup with a Roux
Traditionally, a roux is a paste made of flour and butter (or in the case of gravy, fat drippings from a roast).
These two ingredients are whisked together and cooked for a few minutes before adding liquid to the pan while whisking vigorously.
At this point you could turn it into a bechamel or a silky smooth gravy like this one. A roux is the building block of a creamy mac and cheese and is great for thickening gumbos, clam chowder, casseroles and dips.
How To Thick Soup with a Slurry
If you find yourself making a stir fry then forget about using a roux. Instead, the occasion calls for making a slurry, which is a combination of cornstarch and water blended together to form a loose paste.
Unlike a roux, which is prepared at the beginning of the cooking process, a slurry is added at the end and whisked into a boiling liquid. It works like magic to thicken everything from stir fry sauces to soups and curries. A word of caution: slurries are great thickeners and a little goes a long way.
A simple way to thicken soup is to puree a portion of it or the whole thing. If you like a chunky split pea soup or black bean soup just puree half of it and add it back to the pan. However, if you desire a silky texture like the one in this creamy pumpkin soup you'll need to puree the entire pot of soup.
When preparing something like beef stew you could fish out some carrots and potatoes, puree them and add them back to the pot.
How To Thicken a Soup with a Reduction
All that is required for a reduction is time. This thickening technique involves cooking a liquid slowly until it has mostly evaporated. What is left behind is a liquid with a syrupy consistency perfect for drizzling over foods.