In Wild Fermentations it says you can culture buttermilk but putting 1/2c store bought cultured buttermilk in with 4 cups of milk and let it sit for 24 hours. So, I did that. Well actually I used a lot more buttermilk because I just poured the rest of the container I had in there. Anyway.....I used whole raw milk and I'm wondering if I should spoon off the cream on the buttermilk. There is about a 1/2 inch of cream on the top. Will it keep better if I remove it? I know buttermilk can last for months if stored in glass.