Hi Eggy,

Here's a good article on how to make a buttermilk substitute. I don't know if the results using it in the homemade sour cream will be exactly the same, but it's worth a try.

Buttermilk Substitute

Also, the shipping overseas is pricey, but you can order powdered buttermilk here:

American Spice at recipelink.com

Happy Cooking,

Betsy
recipelink.com