Blood

Blood is the traditional thickening agent in coq au vin, the French rooster in wine sauce, and in braises of game animals (civets). It’s about 80% water and 17% protein, and consists of two phases: the various cells, including the red cells colored by hemoglobin, and the fluid plasma in which the cells float. The plasma makes up about two thirds of cattle and pig blood and contains dispersed proteins, about 7% by weight. Albumin is the protein that causes blood to thicken when heated above 167°F/75°C .