Why did the steak get a crust? (Part 1)

If you read my last post, we went to some trouble to get a nice crust on the steak.  Why did we have to use corn starch and the freezer to get that crust? 

In some of the recipes in class, we have to caramelize onions.  The challenges with caramelizing onions is a great demonstration of what happens with the browning on the steak.  One of the problems with caramelizing onions is that nothing happens for a very long time and then in the blink of an eye, the onions are burned.  So what’s going on here…..

Onions are mostly water, so when we are cooking the onions, the temperature can’t rise above 212 degrees while the water is driven out of the onions.  Once the water has reached a low level, the temperature begins to take off and increase rapidly possibly burning the onions.  So, browning requires a temperature above 212 degrees and a minimal amount of water.  Onions also have a lot of sugars in them which caramelize as the temperature rises.

Referring to “The Science of Good Food,” we see that browning requires temperatures above 250 degrees and water content that is not too high or too low.  This nonenzymatic browning (without sugar) is known as the Maillard Reaction named after Louis Maillard who discovered this in 1910.

So we have two types of browning – enzymatic and nonenzymatic.  (Enzymatic is the browning of foods like apples that brown as a result of oxidation, not heat).  The nonenzymatic browning also has two types – caramelizing of sugar (as in candy making) and browning where proteins are present. 

The browning with proteins only happens in an oven, grill or broiler or in a pan with hot oil.  If a protein is in a pan with water, it can’t get hot enough to brown.  The Maillard reactions creates many different flavor compounds because the amino acids in the proteins add more components to the browning mix.  This process begins with the amino acids from a protein change interacting with sugar molecules from glucose in the meat or a starch in flour on the surface of the meat.  As the temperature increases above the 250 degrees, the molecules form an unstable structure that then begins to break down into many, many by-products creating the variety and complex flavors of a nicely browned piece of meat.

Stay tuned – next post – so what does all this have to do with a great steak……