The ordinary butter moisture test, in which a metal cup is heated over a flame, cannot be used for determining the percentage of water in cheese because the high temperature developed in operating that test drives from he cheese other substances with the water. Also, particles are lost by spattering when the cheese is heated with any degree of rapidity in the shallow butter-moisture cups. To overcome these difficulties, the new method here described has been developed for the purpose of determining the percentage of moisture in cheese. The apparatus consists of: 1 double-walled copper drying cup 1 centigrade thermometer registering to 200° 1 alcohol lamp 1 tripod 1 special flask 1 scales sensitive to 0.01 gram 1 set of weights, 0.01 to 100 grams The body of the copper drying cup may be made in two parts. One of the parts is a jacket that forms the outer wall of the apparatus. It has a flat bottom 4½ inches in diameter, and the perpendicular wall is 4½ inches in height. The inner part of the cup must have a flat bottom 2¾ inches in diameter and a side wall 3¾ inches high. A flange attached to the upper rim of the inner part extends out at right angles to the cup wall and forms a cover for the space between the walls when the two parts are put together. The flange is bent down around its outer edge to make it fit snugly over the upper rim of the outer jacket. It thus holds the inner cup securely in place, leaving a space about ¾ inch wide for oil between the walls and bottoms, and permits the apparatus to be taken apart readily. A circular opening about ½ inch in diameter is made through the flange to permit the insertion of a thermometer for taking the temperature of the oil or the melted fat which is used in the space between the walls. Lard or tallow serves best for use in this space; a readily inflammable oil should not be employed. The thermometer may be permanently held in place by passing it snugly through a hole bored in a cork, the cork being then fitted into the hole through the flange. A flat metal cover is placed on the cup when making a test. This cover has a hole through the center just large enough to permit the neck of the drying flask to extend up through it. The cover assists in keeping the body of the flask at a constant temperature by preventing the entrance of cold air currents. The thermometer should register changes in temperature between zero and 200° C. The alcohol lamp should yield a flame about ¼ inch in diameter and ¾ inch high. The tripod should be about 6 inches high and of proper diameter at the top to support the oil bath.