原始链接参见 http://en.wikipedia.org/wiki/Consomm%C3%A9#Gelatin-filtered_.22consomm.C3.A9.22

Freezing a water-based solution converts all bulk water into ice crystals, but water associated with solutes—in the case of a soup stock, gelatin, fat, and flavor compounds—remains unfrozen to much lower temperatures; in practice, the freezing temperature of this associated water is well below the reach of conventional freezers. Thus, gelatin filtration works by freezing a gelatin-containing, water-based solution and then allowing it to thaw in a mesh strainer at just above the freezing temperature of water. The gelatin and other solutes concentrate in the unfrozen, associated water, and the gelatin forms a stable network through cross-linking, just as it would in a standard gel. This stable network acts as a filter, trapping large particles of fat or protein, while allowing water and smaller, flavor-active compounds to pass. As the bulk water melts, it passes first through the gelatin network and then through the mesh strainer, into a receiving vessel. Because the temperature is kept just above the freezing point, the bulk water melts slowly and, as it is strained into a separate vessel, it is never in contact with the gelatin for long enough to begin dissolving the gelatin network. After all of the bulk water melts, the gelatin network remains in the strainer with the trapped macroscopic particles, and the clarified stock (the bulk water and flavor compounds) is collected in the receiving vessel.

至于健康与否，一般来讲肉汤固然鲜美，营养价值却不高。即便你熬汤熬到肉烂骨酥，绝大多数营养物质还是在肉里的。