How do I keep my grains alive and happy while I'm on Vacation?

Storing kefir grains for a week:

Place your kefir grains in milk. If you have 1 tablespoon of grains, store them in at least 2 cups of milk, 3 is better. I like to make sure that they have plenty of food to eat. If you have more grains, add more milk accordingly.  Then you place this in the refrigerator. This will last for one week. Coming home: When you return home strain off the milk that the grains were resting in and discard (you can also give this to pets!) and put them in new milk to make kefir. The grains will be a little slower making kefir when you first take them out of the fridge. The cold slows them down a bit, but the second time you make kefir they will be back up to speed.

Longer than a week: 

If you’re going to be gone for more than one week, then I recommend you freeze them in milk. Store them in a jar in the amount of milk you regularly use, leaving a little room at the top for expansion when it freezes. Store in a glass or food-grade plastic jar with a lid and place in the freezer. You can store this for several months and they should be fine. They will take a little while to wake up when you remove them from the freezer, but once they thaw, strain them and give them fresh milk After a few days of making kefir, they should be fine. You will need to discard the milk they were stored in. Freezing kefir grains should only be done once in a while. Freezing and thawing them continuously can diminish or kill them, but once or twice a year should be fine.