If the kefir is ready, but you don’t feel like straining it right now, just stick it in the fridge. This halts the culturing process without hurting the grains, and you can neglect the kefir for a little bit longer without it becoming too potent to consume. Put it in front of something you use daily, though, like the Brita pitcher, so you don’t forget about it for too long.
(If I need to halt my kefir for more than a day, I put it in the fridge right after adding the grains to fresh milk. You can leave it for up to a week this way.)