When Erasto Mpemba was in high school, the Tanzanian student asked a visiting professor, Denis Osborne why hot (212° F) water would freeze faster than warm (95° F) water. Osborn did not have an immediate explanation but had a technician perform the experiment in his lab. The technician confirmed that the hotter water did indeed freeze faster than the cooler water.
Mpemba was not the first to have discovered this effect. Aristotle, Francis Bacon, and René Descartes also made similar observations.
Does the Mpemba effect always occur? No. It depends on gas and dissolved mineral content in the water, container size, composition, and shape, and the environment around the container of water. The reasons for the Mpemba effect aren’t well understood, nor or the conditions under which it occurs. Some factors put forth to explain it are evaporation, dissolved gases and minerals, temperature distributions in the water, supercooling, and changes to the surrounding environment.
Wednesday, January 12, 2011
McMurray Hatchery blog (if you are into chickens, it's a site you MUST visit), written by Matthew Pressly. While it doesn't have a lot to do with cooking, it may have some applications in the kitchen (when making ice cream, ice cubes, etc.).
Tuesday, January 11, 2011
|Burger King's new "stuffed" burger|
My dad, however, was the king of the stuffed burger back in the 1960s, long before I'd even heard of Burger King. I always felt burger joints were cheating by just putting a slice of wimpy American cheese on top.
Here's how he did it:
First, he mixed up his hamburger, using ground chuck, salt and pepper, and finely chopped fresh onion. If he had to stretch the meat to feed a guest or two, he'd throw in a cup of breadcrumbs. He then patted out about a golfball-size piece of hamburger on a wax-paper-lined cookie sheet until it was about 1/8th inch thick. He made twice as many as there were people to feed. When the cookie sheet was full, it went into the fridge, as did the next one. While the meat was firming up a bit, he'd slice the Cracker Barrel sharp cheddar thinly. When the grill was ready, he'd put cheese on half the thin burgers, then top them with another thin burger and pinch them all around before putting them on the grill. When they were toasty on the outside, he'd pull them off the grill, put them on a toasted bun and serve them with mustard, mayo, ripe tomato slices and crisp iceberg lettuce. One bite and we were in heaven; the crusty outer meat had a juicy interior, with melted cheese oozing all around.
When I grew up, my creations got a bit more gourmet: I liked to use blue cheese, or Colby jack and jalapeño, or capers and goat cheese. But I always used the same technique; it still makes the best burgers I've ever tasted.