For the last year or so I've had my kefir grains in a silicone tea infuser. It was awesome because no straining required, just move the infuser to a new jar of milk. But I didn't like that the grains didn't have room to grow, so I just recently switched them to a muslin bag. I just drop the bag into the jar and then when it's done, fish the bag out and drop it in a new jar of milk. Things have to be easy, or I get lazy and don't bother to keep up with them