Natural yoghurt is expensive and perishable. It's less costly when bought in the larger sizes, but your family may not be able to eat a quart before its expiration date. If you are unable to eat all of your natural yoghurt, you can save it by freezing it. Another reason to freeze natural yoghurt is to make a frozen yoghurt dessert. Stonyfield Farms and Fage Yogurt, two top makers of natural yoghurt, provide directions for freezing natural yoghurt.
Prepare your yoghurt. If it is in small, unopened cartons, wrap the whole carton tightly in cling film to prevent freezer burn, and then pop it in the freezer. Use within a month or two.
Transfer the yoghurt into smaller containers with airtight lids if you are freezing yoghurt from a large tub. Freeze and defrost as needed.
Make frozen yoghurt. Beat egg whites, cream, vanilla and any other flavourings you like into your yoghurt, put it in the freezer. Remove and stir every half-hour or so until it is frozen. Store for 4-6 weeks. Or use an ice cream maker, following the manufacturer's directions for frozen yoghurt. Fage has several recipes for frozen yoghurt on its website.
When you are ready to eat your yoghurt (unless you have made it into a frozen yoghurt dessert) let it thaw at room temperature, then stir it a couple of times before eating. Frozen yoghurt desserts have less fat than most ice cream. The beneficial bacteria in yoghurt is still viable once it thaws, either in your kitchen or in your digestive tract.
Once yoghurt thaws, it will not have the same consistency as fresh, natural yoghurt.