If I leave town for 2-4 days, I put twice as much milk as normal in a half-gallon jar and just leave it on the counter. If you refrigerate your kefir grains, they become dormant. They will still make kefir when you return, although your first couple of batches may take an extra day. But they may never grow, thrive, and multiply/ reproduce again. Therefore, when I leave town for more than 4 days, I have a friend babysit my kefir grains and give them fresh milk every 2 days. I have no problems putting my water kefir grains in the fridge, though.