Collagen becomes gelatin
Tough cuts like beef shank, oxtail and chicken feet are packed with collagen, a stringy connective protein. Hours of gentle, moist heat unwind it into gelatin. That's why good stock wobbles in the fridge, and why the meat turns tender.
Cook collagen low, slow and wet
Collagen needs moist heat, a bare simmer and time: often 2 to 3 hours for a braise, longer for bone stock. Fast, dry heat just tightens the muscle fibers. Short ribs rushed at high heat come out tough and rubbery.
Test yourself
Questions from the interactive lesson, with the answer and the why.
Your homemade bone stock jiggles like jelly after a night in the fridge. Why?
Collagen turned into gelatin, which gels as it cools. Long simmering melts collagen into gelatin, and gelatin sets when chilled.
True or false: Boiling a stock hard for an hour gives the clearest, silkiest result.
False. A hard boil churns fat and protein into the liquid and clouds it, while a bare simmer stays clearer.
What went wrong? You boil beef chuck hard for 40 minutes. The meat comes out dry and chewy.
The heat was too high and the time too short. Collagen needs hours at a bare simmer. A hard boil toughens the fibers.
Fill the blank: Long, moist heat melts collagen into ___.
Long, moist heat melts collagen into gelatin. Gelatin is what collagen becomes, and it thickens stock.
You want the richest, wobbliest stock. Which bones do you buy?
Feet, wings and knuckle bones. These are packed with collagen, which becomes gelatin and body.