If I run my cider thru a filter while getting it into the keg, Does that filter enough of the yeast out so I can then back sweeten it? Or do I need to go thru the process of killing off the yeast?
If you’re keeping the cider cold in the keg, I don’t think you have to worry about the yeast (unless it is Lager yeast).
Definitely maybe! :) It depends on the type of filter and how large the pores are. Course filters will allow yeast through, fine filters will not. A 1 micron filters will remove yeast cells - sometimes it’s called a ‘sterile filter’. A courser filter may remove some, but perhaps not all. As dannyjed said, keeping the keg cold will help keep any remaining yeast inactive.
If you’re not sure, you could stabilize it with Campden and Potassium Sorbate. I stabilize my ciders because I tend to send them to competitions and I don’t want to bottle blowing up on the way or when the open it. 1 campden tablet and 1/2 tsp sorbate K per gallon.
+1. I stabilize too.