Dear Mr. Scientist: What's the best way to caramelize food? I've heard for onions you're supposed to go slow at a low heat, but then for scallops it should be fast and at a high heat. Why is there a difference?
—Deb S.
What you're describing are actually two different processes: Caramelization and something called a Maillard reaction. While caramelization occurs with foods that only contain sugar, Maillard reactions occur in foods like meat, bread and barley that contain both sugar and protein. Both processes involve multiple reactions that break down large molecules in the food and recombine them to form new, different-tasting compounds.
With caremelization, water is removed from large sugar molecules, the sugars are broken down into smaller molecules and the small molecules come together to form sweet, delicious caramel. When it comes to caramelization, low and slow is the way to go. It's just like roasting a marshmallow; don't get too close to the fire, take your time and you will be rewarded with a golden brown marshmallow, but stick it right into the flame and it will just start on fire and end up burnt and black.
Scallops on the other hand involve the Maillard reaction. This process is very similar, except now the broken down sugars react with the amino acids from broken down proteins. Again the smaller molecules recombine and produce larger molecules that give the food its new flavor and brown color.
Dear Mr. Scientist: I'm sure you've seen the Mentos and Diet Coke phenomenon. How does this work and does it have to be Diet Coke and Mentos or will other combinations of candy and soda work?
—Lori L.
How these fountains work isn't exactly understood, but thanks to the Discovery Channel's ""Mythbusters,"" we've got a good idea. The potassium benzoate (a preservative), aspartame (an artificial sweetener) and carbonation from the Diet Coke, along with the gelatin and gum arabic from the Mentos react, quickly releasing all of the carbon dioxide . This reaction is further accelerated by the tiny holes on the surface of a Mentos where the CO2 bubbles are able to form and grow. If you don't have Diet Coke or Mentos, using Lifesavers and most other diet sodas will do the trick.
