When you cook a tough cut of meat, the hard-to-chew collagen in the flesh breaks down into gelatin, which is what gives the finished braising sauce its silky richness. The more gelatin in the sauce, the more tender the meat. To demonstrate how gelatinous the braising sauce is at each stage in the cooking process, the cooks at America's Test Kitchen chilled a sample of the sauce after one, two and three hours of cooking.
Not surprisingly, the sauce after one hour was loose and mushy, while the three-hour sauce stood up as firmly as a slice of Jell-O on the plate. It's a visual reminder of why tough cuts of meat need so long to cook, and why you shouldn't waste a single drop of their delicious braising liquid.
→ Read more: We Prove It: Cook Tough Cuts Beyond Well-Done at America's Test Kitchen
(Image: Faith Durand; America's Test Kitchen)