With Kefir, one is introducing the Kefir fermentation bacteria to the milk, so the result is much better tasting than sour or spoiled milk. More like the flavor of buttermilk.

Organic Valley has awesome whipping cream, and it’s probably grass fed vs feed lot fed. 🙂

Athena, For grass-fed heavy whipping cream, we recommend eatWILD to find local farms that have grass-fed dairy.

Martin, We don’t know the macros for soured milk, sorry for any inconvenience!

Steph, I’m not familiar with table cream, but I’m thinking it’s probably close to what we know as light cream. In general, heavy cream is higher in fat and lower in carbs so that’s what we tend to buy. But the amount of carbs isn’t all that different per serving and to avoid waste, I would just use up what you bought and then buy heavy cream. And yay, welcome to the keto family! 🙂