MIC of K-Sorbate?

Anyone have any idea what the minimum inhibitory concentration of potassium sorbate is? I'm making some cider, and am using primarily juice with only ascorbic acid, but want some American-Soft-Cider-Juice (or whatever you want to call it) character to it. The only "Cider" I can find has 1/10 of 1% potassium sorbate in it. I've read several other posts about fermenting juice with this stuff in it. Starter, check. Yeast nutrient, check. But what about diluting it? Has anyone ever tried that? I'm thinking about 1:4 ratio of the sorbated stuff to the non-preservative stuff.

You might find some useful info here: Wiley InterScience :: Session Cookies Regards, GF.

1 Part K-Sorbated Cider to 4 Parts No-Preservative Juice seems to ferment just fine, if you add enough yeast. My first pitch didn't seem to do anything after 48 hours. I got nervous and dumped in a packed of SafeAle-5 and it was going by the next morning.