Well, I started with three jars of cream, I was planning on trying three ways of making sour cream per my reading.. Jar a) Cream allowed to sour naturally b) Cream mixed with 2 tbsp of sour cream with active cultures c) cream mixed with live active cultured yogurt..
End results, cream A- allowed to naturally sour take five days, and I can see using it in cooking or baking but not for dips or eating.. it was to sour by the time it was thick and ready..
Cream C- it turned into very nicely cultured cream after two days but never thickened up, but it made awesome cultured butter..
Cream B- it took 48 hours but it made awesome sour cream, thick and flavourful and a total hit! Love it.. Here is a side by side of the store (gotten in the smallest amount to get the sour cream culture) and the homemade.. Can you spot the difference?
Just another Day on the Farm 
Hmm, now would that be the one with all the beautiful peaks and valleys (as opposed to the boring looking blob on the other side?; )
no, it would be creamy looking boring stuff lol
Oh shoot! I WAS torn between colour (richer on the left) and texture (appears thicker on the right), so I flipped a mental coin and guessed (wrong, unfortunately):
We always used cultured buttermilk from the store for our sour cream and to clabber milk for our cottage cheese.