Fresh pressed cider not starting fermentation?

[ApplePressing]

We're new around this forum, but are having an interesting issue so we thought we'd throw it out there in case anyone has any advice.

We're brewing a large amount of hard cider (80+ gallons) with apples we pressed ourselves (treated with campden tablets 24 hours before pitching yeast). We've divided the cider into various 15 gallon containers and many 5/6 gallon carboys in order to experiment with various yeasts and flavorings. All but one of our 5 gallon carboys started fermenting with 48 hours, however one still hasn't started and it has now been a week. Same cider, same initial S.G and same yeast (champagne) as a few others. The only difference was that we added a little of simple syrup to this one to up the alcohol content a bit (though we added the same simple syrup to a couple other batches, which seemed to start no problem).

Any guesses as to why it wouldn't have started? And, is it too late to save it somehow? (Cider was pressed on 9/27 and yeast was pitched on 9/29).

 

[Yooper]

I have no idea- but if the SG is the same, I'd add more yeast right away.

 

[Randzor]

Check your air lock also. Might be open to the air and thuse not showing fermentation.

 

[ApplePressing]

Thanks!! The S.G hadn't changed at all, so we went ahead and added more yeast as well as refitting the airlock a few days ago. I guess we'll just have to give it a few days and see how it goes.

Even if this second batch of yeast does start to ferment, should we pasteurize the cider (or treat it somehow) since it sat unrefrigerated and not fermenting for a full week?