pasteurization?

i made a cider using cider that i pressed myself. i thought that typical juices and ciders of apples are pasteurized and the pasteurization prior to the fermentation process would affect the yeast life. does pasteurization before i turn the juice into hard cider actually do anything? i cant seem to find anything that supports this?

It has no effect on fermentation.

Except that it kills off wild yeast that would have been on the skin. The byproduct would positively effect fermentation, by making it clean.

i used potassium metabisulfite as the kill step for wild yeast and bacteria

I heat pasteurize all my juices prior to ferment by heating to 160-170 F for 15 minutes. Kills everything without killing any flavor. Then cool and pitch the yeast that you want (I love Cote des Blancs!).

A local orchard offers fresh cider (in season) either non-pasteurized or heat treated pasteurized. Is there a preference one way or another related to the taste of the end product?

I prefer the taste of a cider with pasteurized juice. I find that even the very best ciders where pasteurization was not done all have a certain "musty" flavor, which is not present when pasteurized juice was used. Also when buying juice from an orchard, I find that the unpasteurized stuff begins to ferment on its own in a matter of a day or two, whereas the pasteurized stuff will last at least a week if not two, so, if you need to hang onto the juice for any amount of time before you can get it into a fermenter the way you want it, it makes sense to buy pasteurized juice. Most places it seems are also using UV or flash pasteurization as opposed to hot pasteurization, and these methods are both effective and should have minimal impact on flavor (except for lack of that mustiness thing I mentioned earlier). So, as with any good question, the answer is......... it depends!