After adding the starter to the cream it must be kept at a uniform temperature of 65 to 75° during the ripening process and it must be watched carefully and occasionally stirred gently until the consistency, aroma and acidity are as desired. Then it should be cooled quickly to stop further fermentation and if it is not to be churned at once it should be kept cold until churning time. Usually it is safer to set the cream in the morning and hasten the ripening so it will be completed in the evening rather than to leave it overnight warm. For, if it is finished in the evening, the cream may be cooled and placed in ice water overnight and one is sure to have it in good condition for churning in the morning. But it is quite feasible for the experienced operator to regulate the process so the cream will not be fully ripened in the morning until he is on hand to watch it and see that the process does not go too far. Taste and smell will tell when it is just right, and the _acid test_ may also be applied to determine when to stop the fermentation. An acidity of .5% is usually desired. When the condition is right, chill the cream, cooling it to below 50°—preferably down towards 40°—and leave it in ice water or in the refrigerator until churning time; then temper it to the proper temperature for churning. Even if it is to be churned soon after the ripening is completed it is best to chill it and then raise the temperature to the point wanted for churning. This gives a better “grain” and “body” to the butter than if the ripened cream is just cooled to the churning temperature, and is especially desirable when the cream has been pasteurized. [Illustration: Branch of the Annatto tree ] =Coloring.=—When the cream is ready it is poured into the churn and a little butter color is added. Some people prefer butter very light or even uncolored, but usually 1 to 2 teaspoonfuls of a standard butter color[5] to 10 gallons of cream will be found right, varying according to the season and the breed of cows furnishing the milk. The butter-fat in Guernsey and Jersey milk is naturally highly colored, while that in Holstein milk is comparatively white. When the cows are on fresh pasture in the early summer the butter-fat is more highly colored than when they are on dry food. The amount of coloring to be added to the cream is regulated to overcome such variations and make the butter of uniform color all the year round. [Illustration: Adding the butter color ] =Churning.=—Hundreds of varieties of churns have been constructed from time to time; 2,000 years ago Pliny described the old dash churn much the same as still occasionally used on the farm, and the principle involved in the process has not been changed. The object is to make the fat globules conglomerate into grains that can be collected and leave as little butter-fat as possible in the buttermilk. [Illustration: Old Arabian churn made out of the skin of a goat ] [Illustration: Ancient churn ]