Summary The Babcock centrifuge and fat testing apparatus were used. The method follows: Add 1 ml. of Sudan III to a milk test bottle, then add 17.5 ml. of milk at 110° F. and shake for 15 sec. Add two 10-ml. portions of distilled water at 110° F., shaking for 30 sec. after each addition. Then fill the bottle to between the 7 and 8% marks with distilled water at 110° F., being careful not to shake. Balance bottle in a centrifuge heated to 110° F., using the outside trunnion cups, and spin for 10 min. Read directly from the centrifuge, the cream volume to the nearest 0.1%. Each 0.1% cream volume is about equal to 1.0% difference in the USPHS Index. Sudan III made the cream volume more distinct. Ethyl alcohol carried the dye. With this method small differences can be detected in fat emulsion stability as affected by some processing procedures.