gelatin concentration Both strongly acid ingredients and the tannins in tea or red wine can cloud a jelly, the acids by precipitating proteins in a meat or fish stock into tiny particles, and the tannins by binding to and precipitating the gelatin molecules themselves These ingredients are best cooked briefly with the gelatin solution so that it can be strained or clarified before setting A number of fruits — papaya, pineapple, melons, and kiwi among them — contain protein-digesting enzymes that break gelatin chains into short pieces and thus prevent them from setting into a gel at all They and their juices can be made into a jelly only after a brief cooking to inactivate the enzymes Cooling Temperatures The temperature at which the gel forms and ages affects its texture When “snap-chilled” in the refrigerator, the gelatin molecules are immobilized in place and bond to each other quickly and randomly, so the bonds and the structure of the network are relatively weak When allowed to set slowly at room temperature, the gelatin molecules have time to move around and form more regular helix junctions, so once it forms, the network is more firm and stable In practice, jellies should be set in the refrigerator to minimize the growth of bacteria Gelatin bonds continue to form slowly in the solid jelly, so snapchilled jellies become as firm as slow-chilled jellies after a few days Jellies from Meat and Fish: Aspics Meat and fish jellies go back to the Middle Ages (p 584), and are still delightful showpieces They’re made much as consommé is, ideally from a flavorful meat stock — often cooked with a veal foot to ...immobilized in place and bond to each other quickly and randomly, so the bonds and the structure of the network are relatively weak When allowed to set slowly at room temperature, the gelatin molecules... move around and form more regular helix junctions, so once it forms, the network is more firm and stable In practice, jellies should be set in the refrigerator to minimize the growth of bacteria... Meat and fish jellies go back to the Middle Ages (p 584), and are still delightful showpieces They’re made much as consommé is, ideally from a flavorful meat stock — often cooked with a veal foot to