Author: emily (Page 15 of 20)

By Chef Joe LaVilla

If there is one holiday menu item that strikes fear in the hearts of cooks, it is the gravy. For some, it is the stuff of legendary failure; for others, it is a long- standing family legacy that has saved even the driest turkey. Whichever camp your gravy falls into, understanding the science behind the technique to making this simple sauce will ensure that the best gravy never fails, and the worst stays out of the garbage disposal.

For those of you who believe that gravy is something that comes out of a packet or jar, let’s begin with the definition: Gravy is a sauce made from the pan drippings of a roast, thickened with a roux and enriched with stock.  Of these three ingredients, the roux is often the culprit of many gravy-pitfalls.  Roux is a mixture of flour and butter that is cooked together, and serves as a thickening agent for hot liquids.  Cooking the flour and butter (or any other fat) before adding them to a sauce serves two important purposes. 

The first purpose is to evenly coat the particles of flour with fat.  If the flour is not coated evenly, adding it to the liquid components of your sauce will yield a lumpy texture.  This process is called gelatinization. When liquid comes in contact with a starch granule, it begins to absorb the water and expand.  If a large cluster of granules comes in contact with liquid, only the outside granules will participate in absorption, while the inside granules remain insulated in the center of the cluster. This cluster becomes a non-giblet lump in your gravy. If you had enough time on your hands, a tiny knife, and a magnifying glass, you would see that if this lump were sliced in half, the very interior would still contain dry flour.  By making sure all flour particles are coated in fat, you have more time to whisk them into the liquid before they gelatinize.  This allows you to disperse them evenly throughout the sauce and achieve that silky texture you want.

The second purpose of the cooking process is to cook the protein that exists in the flour and toast the starch. These reactions prevent the underlying “floury” taste of some gravy. Let’s take a look at the structure of these starches and the effect they will have on your gravy:

 Amylose and amylopectin are the two main starches found in thickening agents.  Amylose is a long chain of sugar molecules connected together.  Amylopectin, on the other hand, is a branched-chain starch.  That means it looks like badly made balloon animal, with parts sticking out from the main chain.  The type of starch present in any thickening agent depends on the plant from which it is derived.  Amylose is typically found in grains like wheat, corn, and rice, while amylopectin exists more often in roots, like tapioca and potato.

The properties of amylose and amylopectin make them react differently when they have gelatinized.  Amylose tends to be able to absorb more liquid, which allows you to use less of amylase-based agents.  It also tends to gelatinize at higher temperatures, which means heat must be used to thicken sauces using this ingredient.  On the negative side, amylase is prone to “retrogradation”.  Retrogradation is the process by which the gel binds to itself upon cooling.  A great example of retrogradation is the texture of rice from Chinese take-out.  Fresh, hot rice is soft and fluffy.  Cold rice is hard and dry–seeming under-cooked.  When you reheat the rice, the gelled starch breaks the bonds to other starch molecules, and the fluffiness returns.  If a sauce thickened with amylose is frozen, it breaks down because ice crystals form more easily.  Another unfortunate process that occurs with amylose starches is synerisis.  Synerisis is the loss of liquid as the hydrated starch sits for a period of time.  This is the liquid seen when lemon meringue pie filling is thickened with flour and sits a couple days—you know—that “tide pool” on top?

Amylopectin gels at a lower temperature.  This allows quick thickening without having to heat the liquid excessively.  It also holds up better to freezing and does not experience synerisis or retrogradation.  Regrettably, for those of you penny-pinchers, the starches that are mostly amylopectin tend to carry a heftier price tag.

Now that you’re well-versed in starches and chemical reactions, let’s talk turkey-gravy! Properly made gravy starts with removing the pan drippings and pouring off most of the fat (don’t you dare throw those drippings away though!).  What little fat remains can now be used as the base for a roux, just by adding a little flour and cooking the mixture.  The stock can now be added, and the basic gravy should be lump-free.  Now you can add some of those drippings back because they have concentrated flavor and salt.  To keep the gravy from being too salty, the drippings should be used as seasoning. In other words add drippings/ taste/repeat. 

Don’t panic if the result is too thin, but step away from the flour container! Adding more flour now will give you pasty tasting gravy. Take a deep breath and reach for the cornstarch to make a slurry (a mixture of cornstarch and COLD stock or water). Adding this little paste to simmering gravy will allow you to adjust the consistency to be the rich, thick gravy that you desire.

And there you have it—holiday disaster diverted! No more suffering though bad, lumpy gravy.  Create a new family tradition of great, silky gravy that compliments your hard work on the turkey.  Now, that canned cranberry sauce is another story…..

To see additional Food Science features click here: FOOD SCIENCE

About Joe LaVilla

Chef LaVilla is the Academic Director for the Culinary Arts programs at the International Culinary School at the Art Institute of Phoenix. Besides being a Certified Executive Chef, Chef LaVilla also holds a certification from the International Sommelier Guild (ISG) as a Certified Sommelier. In addition, Chef LaVilla is experienced in food styling, food and wine pairing, the hospitality industry, culinary arts management, and more.

Before joining The Art Institute of Phoenix, LaVilla had been Executive Chef for Tucchetti restaurant in Phoenix. He has worked for Mark Tarbell as well as Wolfgang Puck. His credits include, “Faculty of the Year” award at The Art Institute of Phoenix; finalist in the Arizona Pork Council Taste of Elegance Competition; and author of the textbook “The Handbook of Wine, Beer and Spirits: A Guide to Styles and Service”.

Chef LaVilla received his Ph.D. in Organic Chemistry from the University of Rochester and his Bachelor of Arts degree, Cum Laude, in Chemistry from Cornell University. He also received an associate’s degree in Culinary Arts from the Culinary Institute of America, where he graduated with honors.