Number 3 “Thickening the Broth” May 16th, 2002
One of the things that all cooks must do from time-to-time is thicken the broth. The broth may be savory or sweet, in soup, stew, chowder, pudding, pie filling or just the foundation for homemade gravy, it doesn't matter. If you cook often enough thickening the broth is something you're going to need to do. In fact, it's one of those fundamental kitchen tasks that separate really good cooks from those who are simply putting dinner on the table. And while understanding thickeners isn't exactly rocket science, it may be more complicated than you think. So in this issue of my newsletter I will explore the methods used around the culinary world for accomplishing what should be, but isn't always, a simple task.
As with many other topics I hope to touch upon, there is wealth of information to be found in cookbooks (especially "teaching" cookbooks, such as The Joy of Cooking, Essentials of Cooking, How to Cook Everything, What Einstein Told His Cook, etc.), cooking magazines and, of course, the world wide web (did you know what the "www" in internet addresses stood for? J ) But my goal is to give you enough information so that you understand that their are options to standard flour and cornstarch slurries, and when it might be appropriate to use a different technique or substance.
Also in this issue I've tossed in a little more southern humor and a cool recipe or two. By the way, I've received a few very nice e-mails from some of you that tried brining, the topic of the last issue, with great success. Thanks for the feedback! The more the better, so please don't hesitate to drop me a note and let me know if you're finding this stuff useful.
You Can Put Something In Or Take Something Out
And this really describes the two basic methods used to thicken liquids. When you take something out, a process called reduction, you use evaporation to thicken a liquid (and concentrate its flavors.) When you put something in, you're using a chemical reaction to bind molecules together. Generally speaking the second method, adding something in, takes less time and is by far the most popular method for home cooks. Reduction is more often used by professional chefs because of the wonderful flavor changes that can occur as liquid evaporates but essential flavorings remain.
This method is actually quite straight forward, but unless you want to intensify the flavor of the liquid being reduced, it probably isn't worth the time it's going to take to get good results. Another reason to use reduction is to avoid the fat associated with using thickeners like a roux (oil and flour mixture), a beurre manié (kneaded butter and flour), eggs or some other fat rich additive. But even if low fat is a goal you can achieve that without spending the extra time in the kitchen to use reduction to thicken liquid. So if you're looking to create a rich wine sauce, or you want to thicken a cream sauce without introducing competing flavors such as flour or butter, then here are a few general tips:
To make a reduction just cook down the sauce in an uncovered pan until it's thickened to your liking.
Glaces are used to create silky smooth sauces but require time and patience. They're made by reducing stocks until they're thick and gelatinous Demi Glace, probably the most famous, is practically an all day project.
If you wish to create a sauce or gravy with reduced wine, a very popular method used around the world, you should start with at least twice the amount of wine that you plan up using. This level of reduction is necessary to build the complexity and intensity required by the sauce. Otherwise you're just wasting time.
This rule-of-thumb generally applies to reducing other liquids as well. For example, when I make my orange reduction sauce for the classic French dish, Duck A L'Orange, I start with 2 cups of liquid (mostly fresh orange juice) only to wind up with ½ cup after the reduction is complete.
You can reduce light cream to achieve the thicker, smoother texture of heavy cream, but with a lower fat content.
Also you can reduce a broth containing herbs and seasonings to draw out and intensify their flavors in a sauce.
But if your goals are a tad less lofty, and what you really want to do is thicken the broth without a lot of hassle, then by all means try...
Putting Something In
There are many different things available to the home cook that are suitable as thickeners. For the sake of brevity I have omitted those that are considered exotic, difficult to work with or to obtain. Basically, sauce thickening techniques can be divided into the following:
While this is not as popular now as it once was, given our relatively new infatuation with healthy cooking, adding fat to thicken sauces and broths has been the key to delicious results for many cultures around the world. Look no further than classical French cooking (many of the variations still bear their French names) or south to America's Cajun and Creole cuisine to see how important this technique is to achieving spectacular results. With this method of thickening, a starch, most often flour, is combined with butter or oil, or sometimes by adding directly to browning, fatty meats, to form a roux (pronounced roo.) The roux is then combined with the broth to thicken and to provide a velvety smooth consistency.
A simple roux is straight forward: put (roughly) equal parts of flour and fat into a sauce pan and cook until completely combined. If this is done only long enough to cook away the raw flour taste ( a couple of minutes) you have what Cajun's would call a white roux. It should be noted that white rouxs are rarely used in Cajun or Creole cooking but they suffice quite well for the home cook simply wishing to "thicken the broth." More complex rouxs require much longer cooking times, near constant attention and vary in color from light tan to dark brown, each being best suited to a particular type of dish. An internet search will produce volumes of information on the proper method for producing authentic rouxs. Once prepared, add your broth a bit at a time, whisking constantly and combining completely before adding more, until the desired consistency is obtained.
A beurre manié (pronounced bare mahn-YAY), French for "kneaded butter," is another combination of fat and flour. In this case the fat is always butter and the mixture is used to thicken at the end of normal cooking time. It can be a life saver if a sauce or stew turns out to be to thin when almost done. Simply kneed (roughly) equal parts of pliable butter and flour together by hand and stir in until completely combined. If thickening with a beurre manié the dish should not be cooked more than an additional minute or two as a starchy taste can develop if allowed to cook longer.
Egg yolks are wonderful thickeners when added to soups and sauces. Just make sure that when thickening with egg yolks, or egg yolks mixed with cream (called a liaison), you temper the mixture by adding small amounts of the hot liquid first, before combining all together. Otherwise you'll end up scrambling the egg mixture.
Butter, added a tablespoon at a time just before the sauce is ready to serve, is another way to thicken. The same is true for cream, once it is reduced. Both of these methods produce excellent results with a silky texture and marvelous flavor. Because neither of these have as much thickening power as when combined with a starch, they represent a very high-fat solution and should be used sparingly.
Another very common method for thickening, and one much lower in fat and calories, is to use water in combination with a starch. When mixed together this is referred to as a slurry. Always start with a cold liquid, approximately equal parts liquid to starch. Make sure the starch is completely dissolved or it may not break down completely once added to the broth. Flour is by far the most common starch used in western cooking and works wonderfully with sauces, gravies, soups and stews. Use 1 tablespoon to thicken 1 cup of broth.
Cornstarch is another popular starch for making a slurry and is widely used in oriental cooking. As with flour, use 1 tablespoon for 1 cup of broth. While cornstarch works very well and is generally easier to work with than flour, it produces a glossy sheen in the sauce or broth and may not be as visually appealing when used in traditional western dishes. Also, cornstarch doesn't do well when dishes incorporating it are to be frozen, in which case you may wish to consider arrowroot.
Arrowroot is an excellent substitute for cornstarch except that it should not be used in sauces containing cream, as it will turn slimy. Except for that, and its somewhat higher cost, it's a great thickener with a neutral flavor, it works well at lower temperatures, with acidic ingredients - which cornstarch does not - and holds up better over prolonged periods of cooking. Arrowroot also produces a nice, fatty mouth feel which is generally associated with fat-based thickeners.
Another wonderful, and generally low fat, method for thickening soups and stews is to puree all, or some, of the starchy vegetables and add back into the broth. When I make potato soup, for example, I puree the potatoes along with some butternut squash to produce a completely fat free soup. My guests don't even realize it has no dairy at all in it. Similarly, when I want to thicken the broth in black beans, red beans or lima beans, I cook the beans until they begin to break down and then mash a portion of them. This results in a creamy sauce for the beans which is wonderful served on top of white rice. Try this method for thickening any type of broth which contains starchy veggies.
Nuts and Grains
Ground up nuts make great thickeners, although they are quite high in fat and can be expensive, at least compared to other thickening methods. On the plus side they work well, are delicious and can add an exotic touch to any recipe. Make sure they are well ground, until they are reduced to a powder or butter.
Another method involves using cereals and grains like corn meal, grits, oatmeal or couscous. Just stir it in until the desired consistency is obtained. Along these same lines, a quick cheat to more elaborate methods is to sprinkle some dehydrated potato flakes into the broth. Works like magic.
While these may not seem special to some, the thickeners in this category are generally not used by most home cooks and may be considered somewhat exotic. For these reasons I mention them here and leave it to you to research their usage if you wish to follow up. In this category, mostly starches, I would include instant tapioca (which is frequently used by home cooks to thicken dessert fillings), kudzu powder (the ground up tuber of this notorious southern vine), lotus root flour, potato starch, sago (from the sago palm), sahlab (made from orchid tubers), rice flour and water chestnut flour.
Lastly are two thickeners that are particularly near and dear to my heart, filé, pronounced (FEE-lay), and okra. Those of you versed in Cajun lore will instantly recognize these ingredients as the essence of gumbo. Gumbo is, of course, the famous concoction, brewed up by Cajun families, immortalized in song and legend and usually consisting of some combination of shellfish, chicken, spicy sausage, the trinity (otherwise known as onion, celery and bell pepper) and stock. And gumbo is traditionally thickened with a roux, okra, filé, or sometimes all three.
Okra is a finger shaped veggie indigenous to Eastern Africa. It was originally brought to the West Indies by Ethiopian slaves who treasured it not only because it is delicious but also for its ability to thicken their soups and stews. This was a wonderful thing for people too poor to afford butter and flour. The word "gumbo" by the way is a derivation of the Ethiopian word for okra. So, naturally, when other West Indian residents observed the cooking habits of the slaves they simply came to call the concoctions containing okra, "gumbo." And this word carried forth when okra, or "gumbo", was introduced into the southern United States.
Filé comes from the ground leaves of sassafras, a plant indigenous to America and widely used by native Americans before the Acadians arrived and incorporated it into their cooking. Filé should never be added to the broth while it is cooking as it has a tendency to get stringy. It may be added at the end, sprinkled on after the gumbo has been removed from the heat. Or, as I like to do, it may be added in the beginning while sautéing the trinity. It will combine completely and then the stock may be added.
A True Southerner Knows...
And now for a little southern humor. This was passed along to me by my Aunt Joyce. She is as southern as southern gets and currently resides in central Florida. Since getting this I have shown it to numerous people and everyone gets a huge laugh out of it - mostly because it's so true!
And now, a recipe or two...
In keeping with our theme here are a few cool recipes that incorporate the information presented above. Connect to the internet and click on the links below to see the recipes.
Cuban Black Beans and Rice
Cajun Red Beans and Rice
Creamy Potato and Squash Soup
Traditional White Sauce
Classic Orange Reduction Sauce
Until the next time.