this is an extremely simple recipe. i would disagree with the former review of finding the recipe off. because sometimes to ferment a dairy product you use an existing dairy product to easily multiply the same kind of culture. like when you make yoghurt at home, you use yoghurt in lukewarm milk to make more yoghurt. so yes, using sour cream makes sense. also there is an option which says buttermilk. use that if you find the use of sour cream as a culture so highly abbhorent! :P

Not trying to knock on the author but.... Anyone else read this recipe and think that it's weird that sour cream is an ingredient for making sour cream? That's like the recipe for making cheese using cheese.