How Do You Like To Thicken Your Sauce?

I was making pot roast tonight for dinner and came to the point when I needed to thicken the sauce and came to thinking of what is the best thickening agent to use for sauce. For many years I would usually go for the traditional blonde or brown roux. I came to thinking though of other things I have used or could use today to thicken sauces. So I'm going to take you through a few different thickening agents, their properties and what their ideal usage is.

So roux, the most basic of thickening agents used in French cuisine. Roux is made from equal parts fat and flour. Depending on what you are intending to thicken with the roux, depends on what fat you might want to use. Classical French cooking calls for the use of clarified butter. Often used to thicken sauces and liqids from braised meats, cooking the roux to darker colors will offer a stronger flavor to your sauce. In Louisiana, roux is used to thicken soups, especially gumbo. Their roux is made from vegetable oil, instead of butter. The roux is cooked to a darker color, almost to a burnt color which is used more for flavor than for actual thickening agent, as sassafras is added as well. One point to note is that the darker you cook a roux, the less thickening ability it will have. One disadvantage of roux, is that it needs to simmer for thirty minutes before the flavor of the flour is cooked out.

Beurre manie is an equal combination of butter and flour kneaded together. Unlike roux, beurre manie is added at the end of the cooking process of a liquid, but the flour is in essence raw and the flavor of raw flour is never truly cooked out of the sauce. The butter does however attribute more flavor in this manner. The butter also adds shine and gloss to the sauce.

Cornstarch is another popular thickening agent, especially used in the cooking of Asian sauces and soups. Cornstarch has an immediate benefit in that it thickens sauces quickly, within a few minutes. Another benefit is its lac of expensive, cornstarch costs just a few dollars a box. However, the drawbacks can be plenty. Although in Asian cuisine, a glossy shine for sauce is desired, this is often not desired in most other cuisines. Another drawback is the long-term instability of cornstarch. After prolonged heating, cornstarch thickened sauces will separate, they are also almost impossible to reheat and retain their viscosity.

Arrowroot is another choice, it is also a favorite of mine for a number of reasons. There is an immediate drawback that keeps most people from using arrowroot, it is extremely expensive. A small jar found in the grocery store can cost more than a large box of arrowroot. Arrowroot works pretty much in the same way as cornstarch, but it has a number of distinct advantages. Arrowroot thickens a sauce quickly, just as cornstarch does, but it does not break down in the same manner as cornstarch. Arrowroot also has a much cleaner flavor than cornstarch, it allows for the true essence of the liquid being thickened to come through. I love to use it with well flavored stocks that I have reduced to a great viscosity, which requires just a small amount of arrowroot to finish. I will often do what is called in French "monter au beurre," this means taking chunks of chilled butter slowly whisked into a sauce to add a bit of viscosity, flavor and shine. I'll get more into this in a minute as it is a separate technique as well.

Liaison, is another traditional French method which utilizes eggs to thicken a sauce. If you have had a creme anglaise, you have had a sauce thickened with a liaison. When thickening a cream sauce, half of the "hot" liquid to be thickened is slowly whisked into the eggs and then the rest of the liquid can be added all at once. The sauce is then placed over a double boiler and whisked constantly until the sauce comes to the desired thickness. Sauces made in this manner are very temperamental. The eggs can easily scramble is heated too quickly, in addition the sauce can not be heated to too high as the sauce will separate. At the same time it can not be stored for too long of a period as the eggs will be unsanitary after being held for too long if it is a warm sauce. Cold sauces like creme anglaise hold for a few days. Just for note, one warm version liaison sauce is called sauce allemande, a personal favorite.

The last category I am not going to explain in detail. Herve This, coined the term molecular gastronomy some time ago. Chefs such as Ferran Adria in Barcelona, along with his American copycats have been using special techniques that use what we chefs once thought of as chemical additives. These additives though have made new textures, without damaging the flavor of the sauce. Lecite is a chemical that helps thicken sauces into a shaving cream type foam. Lecite is often used with juices and pure liquids to preserve their pure flavor while giving them a distinct texture. Glice is another chemical used that emulsifies liquids with the addition of a fat. Olive oil is one of the most popularly used fats for this preparation in making a sauce or foam. Again, in this case no flavor is added, just a desired texture.