I did, and I'm not sure I liked it.
First off, I have been getting good results (nice firm consistency, good flavor) from using raw cream (1 pint) and cultured buttermilk (2-3 tablespoons). Sometimes not as thick as others, but generally very good.
Going by the "if it ain't broke, monkey around with it some more" tradition, I ordered creme fraiche culture from http://www.cheesemaking.com because I was ordering a Christmas gift for someone from them anyway. Their formula called for a quart of light cream to one packet of the culture. Heat the cream to 86 degrees, add culture, set 12 hours or until firm.
I followed their formula exactly the first time. Well, the cream did heat to about 100 degrees, but I didn't add the culture until it had cooled.
I have two problems with it. First, the consistency is odd. It's a lot like panna cotta or jello, so it has a funny gelatinous look & feel to it. Not quite what I want in creme fraiche. Second, the taste (so far) is more like sour cream and is definitely bland. I'm leaving it in the fridge for awhile to see if it develops.
I got five packets of the culture for $5.95, so I will definitely try it again. I think next time I'll use a pint of raw heavy cream and see if that makes a difference.
So, has anyone tried culture from this company? Or does anyone have insight?