When should I Force carb?

I have an alt i recently kegged and lowered the temp to around 48*. I plan on lagering it there for at least 3 weeks. Should i force carb now, or wait till it’s done lagering? Does it make any difference?

No difference that I’ve found. I force carbed while I lagered my last Alt. I can’t imagine why it would matter.

At minimum, purge the O2 and pressurize every now and then enough to ensure good seal.

My first and only lager was force carbed while lagering.  It appeared to have no noticable effect.  I did it at the recommendation of other members on this forum.