Ways to Thicken Sauces

Whole books have been written on the subject, and careers have been spent mastering the art of sauce-making. Sauces, unless they are jus type sauces, shouldn't be thin and watery. There are many ways to thicken a sauce. Here are a few sauce-thickening techniques that have been used through the ages:

Ancient Roman Sauces

In De Re Coquinaria, the only cookbood surviving from ancient Roman times, Apicius sets the thickening precepts that are still in use to thickened our modern sauces: vegetable and fruit purees, nuts, egg yolks - both raw and cooked, bread, even pure starch. Flavouring was provided by about half a dozen herbs and spices, vinegar and honey are common ingredients too. Saltiness and savouriness were supplied by a type of fermented fish sauce called Garum.

Using eggs to make custards was one of the main ways that the Romans used eggs and they made both sweet custards (with honey) and savoury custards (with herbs) that were both typically flavoured with fish sauce and black pepper. Sweet custards would have fruit and pine nuts and savoury custards would have meat and fish in them.

Middle Ages

Between Apicius time and the Middle Ages not much is known about cooking. The oldest cooking manuscripts that survived were dated from the 14th century. They describe major changes in the techniques used to prepare sauces. Medieval sauces tend to use many spices. They were thickened with bread and vegetable purees, and meat started to be used as a thickening agent. Chopped hard-boiled egg yolks were commonly used as a thickener for stews. Pure starch was no longer in use, cream and butter still weren't. If the texture agents haven't change much since the ancient time, the flavouring agents have. The Roman fish sauce, garum, disappeared and was replaced by vinegar and unripe grape juice: verjus. Thanks to the discovery of new worlds in the East and the Middle-East new spices made their ways into European sauces: cinnamon, ginger or grain of paradise. The introduction of almonds from the Middle-East made it the main nut used as a thickening agent.

Classic French Sauces

The French, with great intestinal fortitude, thickened sauces with butter, flour, egg yolks, and cream, to name a few. They whisk together butter and flour (a roux) and then add in milk (a béchamel) or stock (a velouté), which thickens almost immediately. They use a paste, or little balls, of equal parts of flour and butter (beurre manié). These were added to sauces or stews as a thickener near the end of cooking. They also used egg yolks whisked into a sauce and reduced cream (cream that has been boiled down to thicken it).

Butter can also be used as a thickener. When it is whisked into a hot liquid, the milk solids and proteins in butter form an emulsion that suspends the particles of fat in the liquid, creating a thicker, shinier sauce. The problem with this last method, however, is that you need lots of butter to make this work (1/2 cup of butter is needed per 1 cup of liquid--1/2 cup of butter is an entire stick!). Other thickeners include blood, foie gras (goose liver), yogurt, fresh cheese, and bread. Prior to the 16th century, coarse bread and ground almonds were the thickeners of choice.

Modern Thickeners

Monter au beurre (sauce made with butter)

This is a French term meaning to finish a sauce with butter. As the last step in making a sauce, you can swirl in chunks of cold unsalted butter, one at a time, whisking until melted, giving the sauce a velvety texture and rich flavor.

Butter and Cream: These flavorful ingredients work to thicken sauces too. However, they are being replaced by other methods due to their waist-bulging properties. Butter added to sauce gives it a shiny, luscious appearance, adds flavor, thickens it, and makes the sauce smoother in texture. Use chilled (practically frozen) butter. Remove the sauce from the heat, and drop in about 1 teaspoon of butter at a time. Don't stir the butter in harshly. Instead, just swirl the pan from and let the butter melt into the sauce. Keep swirling the pan until the butter disappears.

Cream lends velvety smoothness to sauces. Use only heavy cream. To know how much cream to use to thicken a sauce, measure how much sauce you have. Use 10-20 percent of that quantity of cream to thicken the sauce. Boil the cream separately for a few minutes before adding it to the sauce.

Beurre manié (French for “kneaded butter”)

Pronounced BURR mahn-YAY, this is a kneaded mixture of butter (or some other form of fat) and flour, sometimes called "uncooked roux", and is added at the end of cooking for quick thickening. The kneading coats the grains of flour in the butter. When the beurre manié is whisked into a hot or warm liquid, the butter melts, which releases the flour particles and promotes thickening. Beurre manié is helpful in creating a smooth sauce as the flour is not added all at once, which means no lumps will form.

Add 2-1/2 ounces of flour to 3-1/2 ounces of butter that's been softened until pliable, but is still cool. Use a wooden spoon to thoroughly mix into a paste. Use an electric mixer for larger quantities. Use immediately or refrigerate. Beurre manie can be added to hot soups, a little at a time, to thicken them.

Unlike roux, beurre manié is not cooked before using. It is also added only at the end of cooking. For this reason, it will need to be cooked after it has been added to the sauce to cook out any raw flour taste. Beurre manié should be added in small increments. The sauce also must be brought to a gentle boil, as it will not thicken otherwise. Add additional beurre manié, as needed, until you reach the desired thickness.

Roux (flour and some type of fat cooked to create a roux)

A roux (ROO) is a mixture of flour and fat -- such as cooking oil, butter, or chicken fat -- that is cooked, then used to thicken sauces, gravies, or soups. A common roux recipe calls for equal amounts of butter and flour, cooked in a saucepan over medium heat until the flour is absorbed by the melted butter. A roux may be cooked longer to develop a darker color and a nuttier flavor. For best results, stir the roux as it cooks.

If you were to cook the flour and butter together first, then you would have a roux. Melt the butter in a skillet or saucepan over low to medium heat; add an equal amount of flour and cook, stirring constantly until the desired degree of doneness. The longer you cook roux the darker it will become. If you do not wish to darken your sauce but merely want to cook out the raw, floury taste of the roux, cook for just a few minutes. You can add the roux to the sauce or vice versa but they must be at different starting temperatures, (at the very least, one room temperature and one hot). You must also gradually add one to the other and whisk incessantly. All of these steps help prevent lumping.

Employing a roux is the premier method for making gravy for your chicken or turkey. After the bird has roasted, add flour to the drippings in the roasting pan, cook for a few minutes, and then gradually whisk in chicken stock. Bring to a near boil, simmer to the desired consistency, and season with salt and pepper.

Rouxs and butter thickeners have somewhat fallen out of favor with nouvelle chefs. There are a few other thickening that are wonderful, and are better for you:

Liaison (cream and eggs)

This is a mixture of cream and egg yolks, used to thicken soups and sauces. To prepare, 3 beaten egg yolks to one cup of heavy cream. Never add directly to hot liquids, or you'll end up with scrambled eggs. Instead, temper the liaison by adding a small amount of the hot liquid to it to gradually raise the temperature.

Finally, sauces can be thickened by adding a liaison, (a mixture of cream and egg yolks), butter, gelatin, and pureed vegetables or fruits. Which of these are utilized will depend on the type of sauce and it’s specific recipe.

Reduction

Your mom called this "cooking down" ... it's the process of cooking a liquid until some or most of the water has evaporated. It is the simplest and most straightforward method of thickening a sauce. This not only thickens a sauce, but it intensifies its flavor. This technique is almost always employed whenever wine or liquor is added to a sauce in order to vaporize the alcohol. But alcohol or not, any sauce that can be cooked can be reduced. Use a heavy pot; sometimes this takes a while, and you don't want to burn your sauce. Bring the liquid or sauce to a simmer, and cook until the required volume has cooked away (i.e., to reduce by half means cook until the volume is half of what you started with). How much to reduce a sauce will depend on the specific recipe. Generally speaking, when the sauce has congealed enough that it can coat the back of a spoon without running off, (known as “nappé”), it is completed. Remember that when a sauce is reduced it will naturally become saltier. Thus, hold off seasoning until it is finished or near done to prevent over seasoning.

Slurry (starch and water)

A slurry is a mixture of a starch, the most common being flour and cornstarch, and cold water. If you add a starch directly to the liquid you are thickening, you'll end up with lumps of starch; thus the cold water. Other starches that are often used are arrowroot (expensive), potato starch, and rice flour. The proportion is 1 part starch with 1 - 2 parts COLD water or liquid. You want to end up with a mixture that has the consistency of thick heavy cream with no lumps of starch still present. Shaking the liquid and starch in a jar works well - again make sure that all the starch is mixed into the liquid. Add it to your simmering sauce using a whisk to incorporate it in quickly (or you could end up with dumplings), bring to a near boil and then simmer until the sauce has thickened. Flour takes longer to cook than cornstarch does which only takes a few minutes.

Starches are most frequently used to thicken sauces, gravies, pie fillings, and puddings. Cornstarch keeps the sauce or pudding relatively clear or translucent such as in Lemon Merinque Pie and Asian sauces, whereas flour turns the sauce, think "gravy", opaque.

Flour

Flour is the most common thickener used in recipes, from turkey gravy to apple pie, and for good reason: It’s versatile, and in most kitchens, it’s always on hand. But flour isn’t a pure starch (it contains protein and other components), so it has only about half the thickening power of other starches. The best flour to use as a thickener is all-purpose flour because it’s higher in starch than other wheat flours.

The proteins in flour make flour-thickened sauces and pie fillings look cloudy - think "gravy." Flour works best for foods that don’t suffer visually from opacity: white sauces such as béchamel, simple pan gravies, beef stew, chicken fricassée, and apple or pear pies. Don't use flour for berry pies or sauces where clarity is important.

There are lots of ways to use flour as a thickener—that’s the great thing about it: You can cook it with aromatic vegetables in the pot before adding a braising liquid. You can dredge stew meat in flour before browning it, and the flour will later thicken the stew. You can mix it with a little cool liquid to form a paste and then whisk it into a simmering pan sauce.

To achieve full thickening power and eliminate raw flour taste, flour-thickened mixtures must be brought to a boil and then cooked for about 3 minutes. But don’t go overboard with the cooking, because flour thickens more as it cools; as a rule, stop cooking gravies and sauces when they’re a bit thinner than their ideal consistency.

Cornstarch

Cornstarch is a pure starch derived from corn. It can withstand a good amount of cooking and stirring before it begins to break down. That’s why it’s frequently used for thickening vanilla pastry cream, banana-cream pie filling, as well as butterscotch and chocolate puddings, all of which are cooked on the stove and involve prolonged heating and stirring. While cornstarch thickens as it heats, it also sets as it cools, so it's particularly useful as a gelling agent for desserts that must hold their shape such as lemon pie filling.

Cornstarch-thickened sauces have a translucent shimmer. Cornstarch is great for delicate sauces and gravies that you want to be translucent, like stir-fry sauces. It’s also a good choice for berry and stone-fruit pies, because it won’t cloud the jewel-like colors of the fruit juices. Since it can handle a good amount of heat, it’s fine for stove-top puddings and sauces that will be reheated. Lemon Merinque Pie also uses cornstarch to keep the color of the lemon filling clear.

More than any other starch, cornstarch is prone to clumping when exposed to hot liquids. To avoid lumps, mix cornstarch with something that will help separate the granules from one another. For pies and custards, combine it with the sugar for better dispersion. For sauces, mix the cornstarch with a tablespoon or two of the liquid called for in the recipe—the liquid should be cool. Simmer the sauce for at least a minute to eliminate the pasty flavor of raw starch.

Cornstarch also sometimes appears to thin as it stands. This is due to a process called syneresis (commonly referred to as weeping). What you'll see is a fluid seeping from the gel. This problem is more evident if the gel (often a pudding or pie filling) also contains eggs or has a high sugar concentration.

How much starch should we use for any given recipe?

In general, the amounts of flour per cup of liquid for a sauce are: Thin sauce use 1 tablespoon flour per cup; Medium sauce use 2 tablespoons flour per cup; Thick sauce use 3 tablespoons flour per cup

But other starches are completely different. For example, to thicken 1 cup liquid with grain starches: Cornstarch use 1 tablespoon plus 1 teaspoon per cup liquid for a medium sauce whereas with flour you need 2. Rice starch use 1 tablespoon plus 1/2 teaspoon per cup for a medium sauce.

Yet to thicken 1 cup liquid with root and tuber starches we need: Arrowroot use 1 tablespoon plus 1 teaspoon per cup liquid. Potato starch use 2 1/4 teaspoons per cup. Tapioca starch (available at Asian markets) use 1 tablespoon plus 1 teaspoon per cup liquid. Quick tapioca use 1 tablespoon plus 1/4 teaspoon per cup liquid.

Purees

Use a cooked vegetable puree to make a rustic sauce. For example, sautéed onions that are braised with a pot roast can be strained out, pureed and whisked back in to the braising liquid to create a flavorful sauce with no added fat. Adding grated potato to soups or stews will thicken them.) OR nut flours

Vegetable soups can get a big boost in flavor and body by pureeing a portion of the cooked vegetables and adding them back into the soup. Use a food processor for best results, and include some of the soup liquid to help the process along. Cooked rice can also be pureed in this way to add to soup.

Grated Potato: You'll need 10 minutes to spare for a potato to thicken and add heart to your sauce, soup, or stew. First run grated potato through your blender or food processor. Then add it to your liquid and let it cook for those 10 allotted minutes (you may need to cook it longer).

Bread Crumbs

Great for adding heartiness to salsa, soups and some sauces, simply add a handful of crumbs to the sauce, stir in, and let the mixture set or cook for about 20 minutes, stirring occasionally. The crumbs will go to work to absorb excess liquid. When the sauce reaches your desired thickness, serve it right away. If you desire a smoother sauce, strain it before serving. Crumbs can either be toasted or fresh.

Eggs

Eggs are used as a thickening agent and this is mainly due to the fats in the egg yolk. Using egg yolks as a thickener remains the basis of custards (and as a result many ice creams) today. Egg yolks make wonderful thickeners--imparting both a rich flavor and velvety smooth texture--but they're tricky to use. You can't just whisk them into a simmering sauce--they'd curdle on contact. Instead, you need to "temper" them by adding some of the hot liquid to the egg yolks, whisking the mixture together, and then adding it to the sauce. To prevent the yolks from coagulating, you need to keep the sauce below 190°, although this rule can be broken if the sauce has a lot of flour in it. Eggs are also used to make sauces as in Pasta alla carbonara.

Egg yolks thicken when heated to between 149°F and 158°F. Many egg-thickened sauces (Hollandaise being the most famous) are the result of heating the sauce to this temperature so that the proteins bond with the liquid to thicken the sauce. Overheating will cause the egg yolk to curdle.

Tapioca

Tapioca is a pure starch derived from the root of the cassava plant, and it comes in many forms. The small granules of pearl tapioca, labeled instant or quick cooking (Minute Tapioca is a common brand), are widely available and work well as a thickener. Tapioca-thickened fillings are crystal clear and have a more jelly-like consistency than those thickened with other starches. Instant tapioca granules don’t completely dissolve; they may linger in pie fillings as soft, clear beads.

It thickens juices faster than flour or cornstarch, so tapioca is great for all fruit pies, especially berry, peach, and rhubarb, which throw off a lot of juice. It’s also great for pies that will be frozen and reheated, because tapioca holds liquid, so the pie filling won’t weep when frozen and thawed.

Don’t use instant tapioca for pies with open lattices or large steam vents because the granules will be exposed directly to the hot air of the oven and won’t dissolve. It’s also not ideal for pan sauces or stovetop custards because it can’t withstand a lot of stirring and boiling.

For best results, let pearl tapioca sit with the fruit for 5 to 10 minutes before you bake the pie so that the fruit juices can begin to soften the granules. And before you remove a pie from the oven, make sure the juices at the center are bubbling, even if it seems the juices at the edge have been fully cooked for quite a while.

Potato Flakes (dried mashed potatoes)

Measure out a tablespoon of potato flakes for every cup of sauce. Potato flakes are pre-packaged dried mashed potatoes, and you can add them as a thickener to country-style sauces and rich gravies, stews, and soups. Avoid this method with clear sauces or sauces with delicate flavors. This is a quick-fix thickening method, so the potato flake proportions are more to taste than an exact measurement.

Gradually add potato flakes to your sauce. As your sauce simmers, add potato flakes a little at a time. Stir to incorporate, giving each addition time to thicken. Add more potato flakes as needed until the desired consistency is reached. Adding foods like potatoes, pasta, or oats to a rich and savory sauce will also naturally thicken the sauce because of the starch present in the food. Adjust the seasoning as necessary. Before serving, taste your sauce and adjust the herbs and spices if the potato flakes have altered the flavor of the sauce.

Using Food Gums

Select your gum. A few of the most familiar food gums that are used as thickening agents are xanthan gum, agar, pectin, and guar gum. They are popular because they only require small quantities to thicken, and they don’t alter the color or taste of sauces.

Combine guar gum or agar with liquids first. Both agar and guar gum need to be mixed with other liquids before being added to sauces or dressings. Agar gets mixed and heated with water first, and guar gum can be added to oils already called for in the dressing recipe.

Add pectin or xanthan gum directly to sauces. In the last 15 minutes of cooking, pectin and xanthan gum can be added right into your sauce. Pectin must be brought to a boil for at least one minute to activate the gelling action. Xanthan gum will thicken without being boiled.