The purpose of pasteurization is to kill harmful bacteria that may be present in milk. UHP (or Ultra-Pasturized) means that the milk has ben heated to a very high temperature (280ºF for 2 seconds) making a very shelf-stable product as the milk can keep under refrigeration for several weeks. But usually we are purchasing what is just known and labeled as pasteurized milk, also called as HTST or High Temperature Short Time Pasteurization, in which milk is heated at 161ºF for 15 seconds. This kind of milk can last 2 to 3 weeks in your refrigerator.With vat pasteurization, milk is held at 145ºF for 30 minutes and then quickly cooled. This retains a high percentage of the milk's natural enzymes and beneficial bacteria which adds to the flavor and heath benefits of the milk. It lasts about as long in your refrigerator as HTST milk. Many people are turning to vat pasteurized milk as an alternative to raw (or unpasteurized) milk which can be difficult to get in some areas. It tends to cost a little more than conventionally pasteurized milk because the process is lengthier and therefore more expensive.
But how does vat pasteurized milk taste? While I like milk, I don't generally drink it as a beverage anymore so I poured myself a small glass and took a sip. The texture was richer and creamier than my usual (2%, organic, homogenized, HTST pasteurized) milk. The taste was milk-like, only amplified with a fuller and richer flavor. It didn't taste quite as sweet and had a slightly grassy finish. It was really delicious stuff, both on its own and in my morning tea!
The cost would prohibit me from buying this milk on a regular basis. Still, I wouldn't hesitate for special occasions or an occasional splurge. I would love to cook with this milk, for instance, using recipes that would highlight its flavor, such as a panna cotta. Or a fresh, homemade cheese would be delicious.
I'm curious how the lower pasteurization temperature and lack of homogenization would affect recipes. Has anyone had any experience with this?
It should be said that the milk I tried was from St. Benoit, a Sonoma County based dairy that makes great yogurt and some of the best yogurt cheese I've ever tasted. They use Jersey cows which are known to produce richer, creamier milk. A quick Google search reveals that many smaller, family-owned dairies across the US are using the vat pasteurizing process and that the milk is less expensive (as with most things!) than it is here.
(Images: Dana Velden)