Mottles in Butter—Their Causes and Prevention

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      • 1
        Mottles appear only in salted butter.
      • 2
        Mottles appear in salted butter in which the working has been incomplete or lacking in uniformity.
      • 3
        Large numbers of very minute water droplets cause butter to be opaque and of light color.
      • 4
        The fewer and the larger the water droplets, the deeper yellow and clearer the color of the butter.
      • 5
        Salt disturbs the emulsion of water-in-fat in butter, causing a reduction in number and increase in the size of the water droplets, and giving such butter a deeper yellow color than it had before salting.
      • 6
        Mottles do not appear at the churn because, even in incompletely worked, salted butter, there is a sufficient distribution of the larger droplets to hide the localized units of the small droplets.
      • 7
        In incompletely or unevenly worked, salted butter, mottles appear about six to twelve hours after working.
      • 8
        The late appearance of mottles in butter that is destined to become mottled, is due to the fact that in such butter the working process did not accomplish a complete fusion and re-emulsion of the water and brine. When this butter is set at rest, an equalization or interchange of the brine and water sets in, owing to the difference in concentration between the different droplets. The water, by osmosis, migrates from the droplets of low concentration to those of greater concentration and vice versa, causing the droplets to become larger. This action results in a partial breaking down of the emulsion, liberating and effecting a running together of the less firmly held droplets and drops. This in turn uncovers and exposes to view sections containing a multitude of minute water droplets, which result in the appearance of opaque, whitish dapples on the one hand; and there is a deepening of the color in those portions where, because of this runningtogether of water droplets, there are fewer and largerdroplets. And the butter looks mottled.
      • 9
        The proper working of butter brings about the necessary fusion of the water and brine and their re-emulsification removing the cause of mottles.
      • 10
        In order to prevent mottles, butter must be worked sufficiently to accomplish this fusion and re-emulsification of water and brine. This point is usually reached, when the butter has been reduced, by working, to a plastic, tough and waxy body. The working must be uniform throughout the churn; overloaded workers and workers improperly set, loose or slipping, will not work butter evenly and are prone to produce mottled and wavy butter.


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