Weird fermentation? Help

Hey folks,

So I'm making a cider that's based on this recipe.

It looks like this:
4.5 gallons of pasteurized apple cider (no preservativies)
4 lbs of caramelized dextrose
champagne yeast
yeast nutrient

I put this beast together 10/21/13. OG read at 1.090 (no doubt because of the sugar). I was a little disappointed because this cider (and my last cider) had high OGs resulting in a very dry and tart cider that is not my liking. I should have used ale yeast...but hindsight yada yada.

I hadn't stirred it or anything and left it in my closet (temp is around 68). I hadn't noticed any bubbles in the airlock and I was worried (and hoping) that maybe the fermentation had stalled. I checked the gravity (10/29/13): 1.051. Took a sip and it tasted pretty good, maybe even a little sweet.

I let it continue in the second fermentor for 7 days. SG 1.030. I noticed that it had some carb to it when I took the reading.

I think cold crashed it for 10 days (keeping it between 34 and 50 degrees the whole time). SG 1.030. I brought it in and moved to a 3rd fermentor, initially planning for it to be there a day or so. It was some what carbed in the hyrdometer too.

I was getting ready to bottle it, but then I noticed it was bubbling in the airlock, like regularly (every minute or so). Worried that I had reawoke the yeast, I figure to let it finish. I've left it in the 3rd for another 14 days at about 68 degrees.

I took a reading last night. It's still at 1.030. However, it appears to be decently carbed (so much so that as the hydrometer sat it rose due to the bubbles).

Forgive the noobness, but never had this happen to me.

Can anyone tell me what's going on and how it affects the cider?

I'd say it's not done fermenting yet. Give it more time. Give your hydrometer a god spin to dislodge bubbles before reading.
Regards, GF.

It's had the same hydrometer reading for 17 days. Doesn't that mean it's stalled or stopped?

Warm it up to about 68*F & see if it restarts, maybe give it a gentle stir. Champagne yeast should take it dry & your last hydrometer reading was 1.030, I think that yeast has the potential to restart & with that much residual sugar, you could end up with your bottles exploding.
Regards, GF.

If it's stalled, can I add campden tablets to stop it from restarting?

Simply adding campden won't stop it, commecial wine yeasts have been bred to withstand campden. You'll have to use campden AND sorbate to do that, it's called "stabilizing." Problem with that is your cider won't carb up & be fizzy due to the chemicals. I don't use sorbate, it tastes nasty to me, but others say they can't taste it at all, it's really up to you.

I'm wondering if you're in a hurry, or if you just like your cider as it is right now, with the residual sugar? You could just bottle, allow it to carb up & then pasteurize. I've never done this, but there are many who have, here's a whole thread on it:
https://www.homebrewtalk.com/f32/easy-stove-top-pasteurizing-pics-193295/

Hope this info helps. Regards, GF.

EDIT: What is the must temp now? Did you use yeast nutrient/energizer/DAP?