For several years the Dairy Department has been making experiments in cream ripening and its relation to butter flavor. In the course of this work certain important facts have developed regarding the causes of variation in quality of butter from season to season.
It is a fact understood by all buttermakers that under natural conditions, most of the difficulty experienced in securing the right butter flavor Occurs during the winter season. The annual loss to the dairies and creameries of the state due to this fact is undoubtedly very large.
Eckles, C. H. and Barnes, S. E.
"A bacteriological study of the college creamery milk supply, A case of putrid butter, Purification of milk by the centrifugal separator,"
Bulletin (Iowa Agricultural Experiment Station): Vol. 6
, Article 1.
Available at: http://lib.dr.iastate.edu/bulletin/vol6/iss59/1