Technique: Cryo-Rendered Duck Breast
Chef Chris Young and Dr. Nathan Myrhvold of Intellectual Ventures – Seattle, WA
Dr. Nathan Myrhvold and Chef Chris Young have developed a technique for rendering duck breast while avoiding that oft-encountered rendering byproduct, overcooked meat. In the pages of their forthcoming 1,500 page cookbook that sets out to teach chefs about the generation of cooking, Myrhvold and Young explain this tested technique for balanced rendering. The secret? Dry ice. “The whole idea is to use cold in balance with hot,” says Dr. Myrhvold, the scientist-cum-culinary innovator behind Intellectual Ventures, the laboratory where techniques like Cryo-rendering were developed.
Traditionally rendered duck breast is scored and seared, skin-side down, for about 80% of its total cooking time. While this results in crisp skin and rendered fat, an unwelcome but consistent consequence is gray, overcooked protein. Myrhvold and Young developed a method that creates a barrier to prevent overcooking: a thin frozen layer that acts as a buffer between the skin and the rest of the duck flesh. The duck breast is completely flattened as it freezes on a block of dry ice, then the fat is quickly rendered on a hot griddle. The breast finishes cooking in a Winston CVap (sous vide would result in watery skin that would have to be re-crisped) and is frozen once more before a final 2 minutes to crisp on the griddle. That final seven minutes of re-freezing is key, as it freezes the same amount of flesh that would normally have overcooked in the final minutes of rendering. Although it’s decidedly more multi-faceted than the traditional technique, Myrhvold and Young’s cryo-rendered duck has crisp skin, evenly cooked flesh, and is less tight—and thus juicier—than the alternative.
Step One: Perforate the skin of the duck breast with a clean, stainless steel dog hair brush.
Step Two: Lay the duck breast in a bed of salt for 4 hours to denature the collagen proteins in the skin and extract moisture (don’t exceed 4 hours as salt will begin to leech into the flesh).
Step Three: Put the breast skin side down on a block of dry ice with a weighted bag on top (cheesecloth weighted with ballast works) to flatten the duck breast. The duck will freeze to the point of rigidity, so it’s necessary to weigh it down to ensure even cooking on the griddle. Leave the breast on the dry ice for 25 minutes.
Step Four: Put the frozen duck breast on an extremely hot AccuTemp Steam Griddle, skin side down, to render fat. Cook for 7 minutes.
Step Five: Wrap the breast with plastic wrap, leaving skin exposed, and cook in a Winston CVap oven.
Step Six: Return the cooked duck breast to dry ice, skin side down, and weigh down with warmed bag for another 7 minutes.
Step Seven: Finish the breast on a hot griddle, cooking skin side down for 2 minutes to crisp the skin and complete the rendering process.