The Food Lab: Better Home Cooking Through Science

fat. As mentioned earlier, pork fat is also softer than beef fat
making it more pleasant to eat at normal serving
temperatures. So, by combining beef and pork, you end up
with a mix that has the great flavor of beef but an improved
texture and softer fat from the pork.
Then what does veal bring to the mix?
The difference between veal and beef is a little more
subtle, having to do with the age of the animal. When a cow
(or almost any mammal, for that matter) is born, its muscles
are not very well developed. Its fat is soft and malleable, its
muscles pale and mild-flavored, with a high proportion of
soluble collagen, the connective protein that transforms into
gelatin as it cooks. It’s the underdeveloped musculature that
gives veal its tenderness, but it’s the gelatin that lends
ground veal its ability to retain moisture. How does this
work? It helps to think of gelatin molecules as individual
links in a very fine wire mesh and individual molecules of
water as tiny water balloons. As the collagen is converted to
gelatin inside a meat loaf as it cooks, these molecules of
gelatin gradually link up with each other, forming a net that
traps water molecules, preventing them from escaping. It’s
this same quality of gelatin that allows you to turn several
cups worth of water into a quivering Jell-O mold with just a
few tablespoons of powdered gelatin.