Store any leftovers in a glass mason jar with a tight lid in the fridge for up to 24 hours. Keep the temperature around 35°F to maintain freshness. You can also freeze the mixture in freezer-safe jars for up to 1 month. Leave an inch of space at the top because the liquid expands as it freezes. Thaw frozen smoothies in the fridge overnight before drinking. Add 2 tablespoons of fresh milk and shake vigorously to blend the separated layers back together. Discard the drink if it smells sour or develops a dull color.