But if you aren't ready to activate your freeze-dried yogurt starter right when you receive it, you can maximize its shelf life by storing it in the freezer. (You can learn more about How Long Cultures Last here.)
Once you've activated the starter culture and started making yogurt, your homemade yogurt is generally good for eating for up to 2 weeks, when stored in the refrigerator.
For re-culturing, we recommend using the yogurt within 7 days to make a new batch. If a longer break is necessary between batches, preserve some active cultures by freezing or drying. Neither method is 100% foolproof, but our culturing community reports a fair amount of success with either.
Short Breaks, Up to 4 Weeks - Freeze the Culture!
Freezing the Culture
- Put fresh, active yogurt in clean freezer-safe containers. We find ice cube trays to be quite convenient.
- Fill each cube with the amount of yogurt that it will take to culture 1 cup of milk. (About 1 Tbsp.)
- Once frozen, store the cubes in an airtight container in the freezer.
Making Yogurt Again
- When ready to make yogurt, remove enough from the freezer to make a new batch, 1 cube per 1 cup of fresh milk.
- Let the cube thaw gradually in the refrigerator. Sudden changes in temperature can be harmful to the culture, so we recommend thawing it in the fridge.
- Prepare your milk for making yogurt according the instructions for your starter culture and add the thawed yogurt cube to the milk.
- The longer the yogurt is frozen, the less potent it will be as a starter culture. It may be necessary to use up to twice the amount if the yogurt was frozen for 3-4 weeks.
Long Breaks, Up to 3 Months - Dry the Culture
Drying the Yogurt Culture
- Spread a small amount (2 Tbsp.) of starter on a piece of unbleached parchment paper.
- Leave the yogurt to dry in a warm, safe spot no more than 80°F.
- Once it is completely dry, store in a zip lock bag in the refrigerator.
- Under ideal conditions, the starter will keep for up to a few months.
Making Yogurt Again
- To rehydrate the yogurt, follow activation instructions included with the starter or watch one of our How-To Videos on Making Yogurt.