Kefir is simply fermented milk, traditionally it was a way to preserve milk without refrigeration.
Single Batch use the freshest jersey cow's milk, which is delivered straight from the dairy to their studio.
Here is some useful info from Suzanne at Single Batch:
What does it taste like?
A bit like plain natural yogurt, with the consistency of drinking yogurt. They don't add anything extra, no additives or perservatives.
Kefir vs Yogurt? (and many other probiotics)
Kefir contains a larger number of good bacteria (5 billion per tablespoon!) and yeasts however, a key point is that the bacteria found in kefir actually colonise in the digestive system vs merely passing through as with yogurt. This means that over time you can actually correct and rebuild the good bacteria in your digestive system and it takes a healthy disgestive system to kick start the immune system.
How to consume milk kefir?
I have about a cup of milk kefir everyday. I know people who just "down" it "neat", which of course is music to my hears! Milk kefir sometimes gets a bad rap for being difficult to drink - of course I disagree, but I do love it when it's at its freshest. If you bear in mind that the kefir continues to ferment once it's been bottled, the kefir doesn't actually go "off as such" but it does get more sour and fizzy with age. I use it all the time in salad dressings, smoothies, cold soups and as a subsitute for natural yoghurt
Kefir milk is 99% lactose free, as during the fermentation process the kefir grains consume the lactose and also create the enzyme (lactase) that your body needs to process lactose - so in fact kefir is used to treat lactose intolerance as well!