By Harold McGee
Today most dairy animals are fed year-round on silage and hay made from just a few fodder crops (alfalfa, maize). This standard regimen produces a standard, neutral milk that can be made into very good cheese. However, herds let out to pasture to eat fresh greenery and flowers give milk of greater aromatic complexity that can make extraordinary cheese. Thanks to newly sensitive analytical instruments, dairy chemists have recently verified what connoisseurs have known for centuries: an animal’s diet influences its milk and the cheese made from it. French studies of alpine Gruyère found a larger number of flavor compounds in cheeses made during summer pasturage compared to winter stable feeding, and more herbaceous and floral terpenes and other aromatics in mountain cheeses than cheeses from the high plateaus, which in turn have more than cheeses from the plains (alpine meadows have more diverse vegetation than the grassy lowlands).