Originally Posted by garbs
I'm getting ready to rack a cider to my keg and would like to backsweeten it as well. I want to add the campden and potassium sorbate directly to the keg instead of transferring to another vessel first. Right now, the cider is in my only 5 gallon fermenter, and I'd rather not rack into my 6 gallon better bottle for fear of excessive headspace.
Is this an option? If I pull the pressure relief valve every now and then, won't the sulfites still be able to off-gas?
Well, it's not the offgassing at all you have to worry about. What you want to do is stabilize the cider first, and then a few days later sweeten it. If you stabilize and sweeten at the same time, the sorbate isn't as effective. Sorbate doesn't kill yeast (neither does campden). What sorbate does is inhibit yeast reproduction, so that they yeast that are in there can't make more yeast to cause fermentation to restart. So, you stabilize first. Wait a few days, then sweeten.
If there is no sediment at all in the fermenter, you could add the sorbate and campden to it (dissolved in a little water or cider first). Then, rack to the keg with the sweetener in a couple of days. If it were me, I'd rack to the larger carboy along with the sorbate and campden and wait a couple of days then sweeten it to taste. Then I'd rack to the keg.