[Iliff Ave]

Sulfite is just Campden, added at 1 Camden tablet per gallon a couple days before you pitch your yeast.  The Campden/sulfite kills off the nasty wild yeasts and bacteria, and while it does hurt beer yeast and wine yeast a bit (caused them to generate more sulfur), the effects fade enough after a couple days that with a healthy pitch they're able to survive it and be the only critter in your cider.

Now, if you're dry hopping or adding other things later in the fermentation, you might want to sanitize with alcohol or more sulfite to prevent any critters from grabbing hold from that point on too.

Thanks. I assumed that after it hit 7.2% abv that dry hopping would have little chance of adding infection. I suppose it already had the pellicle by that point anyway...

I will give another one a shot in a couple of weeks and see what I get.

[dmtaylor]

I'll just reiterate: Sulfite may be the most commonly used option.  However, personally, I'm an advocate for pasteurization instead of sulfite, as I don't like chemicals in my cider.  I've done it both ways but I prefer pasteurization.  I heat my juice to just 160 F for 10-15 minutes, cool and pitch.  No sulfites, less harm to the yeast that's pitched, less farty sulfur generated, minimal loss of aromatic compounds -- my cider is much more aromatic than many others I've tasted.  Just another option.  Neither way is "wrong" in my opinion, but either method will prevent contamination.

[Stevie]

He's using shelf stable bottled cider. The infection isn't coming from juice. The infection is coming from sanitation.

[udubdawg]

let me be a little more specific than when I said sulfite needs are highly dependent on pH: 

You need almost 10x as much at pH 4.0 as you do at pH of 3.0.  And at the high end you are quickly becoming undrinkable burning matchstick juice.

I don't have a cider chart handy but google something like "sulfite wine chart" to get numbers.  And know your pH.

If the sanitation problem is happening early on then I suppose an initial sulfite dose could help.  But better to just fix the problem, sulfite after fermentation and keep things clean. 

[Iliff Ave]

Sorry. My lack of knowledge on the topic seems to have complicated matters. Sounds like since the juice was warm on the shelf, it was already pasteurized and shouldn't be the issue.

I found a pretty basic article which has clarified things a bit for me.

What are the effects of a juice with preservatives? EDIT- nevermind. sounds like they kill yeast...