How to make Cultured Butter & Buttermilk

As an avid baker of cakes, cookies & bread I go through a lot of butter.  Here in Humboldt County, California we are fortunate to have access to good butter, but I'm annoyed at all the packaging.  None of it is recyclable. So, I think I found a better way and one that fits my DIY sensibilities.  I'm making my own butter - and since I like to tinker with cultured things, why not go swanky and make it cultured. Here is how I do it:

2 quarts heavy cream or manufacturing cream (avoid using products with added thickeners; if using raw cream, pasteurize it at 145°F for 30 minutes).

3.3 ozs (100 ml) prepared Meso II, Aroma B or Flora Danica culture (I used Hoegger's Chevre). Any other mesothermic culture will work - flavor will change based on culture used.

Warm cream to 57-61°F and stir in prepared culture; let ripen for 20 hours at 57-61°F, then refrigerate another 4-6 hours. Let warm up to 50-54°F before processing in food processor.