Back sweetening with juice.

[beerkench]

I plan to keg my cider soon and back sweeten with half a gallon of must that I saved and froze, and wondered if it's a matter of filling the keg with both and then adding some the stabilizer (potassium sorbate).
Do I need to make a solution with the stabilizer first or is it good to add in its powder form?
The keg will be stored cold but I were to fill a few bottles from the keg after carbonation, would there be chance of fermentation starting up in these?

 

[Newsman]

Yes, there definitely will be a chance of fermentation restarting in the bottle. I would definitely use K-Meta and Sorbate to reduce the chances of this happening, or bottle-pasteurize immediately after bottling from the keg.

 

[beerkench]

Yes, there definitely will be a chance of fermentation restarting in the bottle. I would definitely use K-Meta and Sorbate to reduce the chances of this happening, or bottle-pasteurize immediately after bottling from the keg.

Do you mean I should add the sorbate again to the bottles?

 

[menerdari]

I second the meta and sorbate, I dissolve both in 1/4 cup of water and mix in well. (I am degassing at the same time)
I don't keg but I imagine if I was I would back sweeten in a carboy and monitor for about a week for any signs of fermentation before kegging.

 

[Newsman]

Definitely do as @menerdari suggests and mix the sorbate and meta into the "finished" product and give it 2-3 days to make sure that does the job. That won't kill the yeast, it just stops it from reproducing, so there may be some re-fermentation until the yeasties die and aren't replaced