I added PS and Campden after sweetening a keg of cider because I forgot to PS/Campden a few days ahead of time, so I just added it after doctoring the batch and decided to see what happens. I have a Pressure gauge on the air out to see if pressure starts to build which would indicate fermentation is occurring. Has anyone done this or does anyone do it regularly without issue?? I would prefer to just open the keg once if there are no ill effects.
Good to know. And thanks Jimmy K, for posting your 1.5 cup concentrated acid/addition dosing technique about a year ago. I used it this weekend and it makes science and control easy and approachable.
here is the info for any curious parties. (the date stamp is wrong but this is the text.)