A comfort food for many, seafood chowder satisfies the desire for a luscious creamy bowl of hearty goodness. Texture is key, though. A proper chowder is thick enough to coat the spoon but not so thick you need to eat it with a fork. Each bit of seafood floats in its own little aura, waiting to be spooned into your mouth along with the spices, tiny veggies and scrumptious milky soup. Getting that creaminess just right can be accomplished in several ways.
Buerre manié, a hand-massaged blend of equal parts butter and flour, is a time-honored and convenient way to thicken chowder. Made in advance, little balls of this thickener magic can be added as needed to your chowder without fear of breaking the sauce.
The other flour and butter marriage is the classic roux, also made with equal parts of butter and flour. Cooked together until the mixture becomes a paste, the flour and butter become the base for many sauces. To use a roux to thicken chowder, add about 1/5 of the broth to the roux; whisk briskly, and allow to simmer for several minutes, stirring constantly. Add the mixture back into the chowder a little at time, stirring it in.
Make 1 to 1 1/2 tablespoons of roux for each cup of liquid.
Cornstarch and flour work equally well as thickeners for soups and chowders. The technique is to make a slurry with a cold liquid; sprinkling the dry flour or cornstarch into a hot liquid will result in lumps and clumps. Using a whisk, briskly and thoroughly combine 1 tablespoon flour or cornstarch with 1/4 cup cold water. Stir a bit at a time into the chowder. Cook for 2 minutes, and then check to see if you have reached the desired consistency. Flour requires a minute more to cook completely. Substitute low-fat or nonfat milk for the slurry water for a bit more creaminess.
If you used a roux in the early stages of the chowder, don't use flour as a slurry for thickening at the end; this may cause hydrolysis, which prevents the starch from bonding with the water and thus from thickening.
Crème fraîche, the French version of sour cream, works well for a chowder that only needs a slight thickening boost. The taste is suspended somewhere between sour cream and yogurt, but crème fraîche has a higher fat content than sour cream. This means you can add it to your chowder without fear of it curdling or separating.
Cooked and pureed white rice is often used to thicken cold soups but works equally well in hot chowder. Potatoes are even easier to use as a thickener. Simply cook -- you can do it in the microwave -- and puree with a bit of water, and then add the puree to your chowder. The high starch content is released during cooking and the starch absorbs liquid in the chowder, naturally thickening it. Use starchy potatoes in your chowder and you might not have to thicken it at all.
Brown russets are the starchiest members of the potato family, meaning you need less to accomplish your thickening goal.