Smoothies can be prepared and kept in the fridge. Make your breakfast smoothie the night before and keep it in the fridge and all will be fine.
Remember to give it a good shake before you consume it. If you put a smoothie made with frozen ingredients in the fridge, the texture and taste will change as the ice melts.
Nothing to worry about.
Be aware that some green vegetables and fruit smoothies will separate if left standing.
They definitely need a shake before use.
Kale and blueberry smoothies are good examples of smoothies that become gelatinous after a few hours.
Shake and perhaps re-blend.
You will also find that flavors will change and lessen over time.
Textures can also change.
All in all, 48 hours is usually the maximum lifespan of a smoothie in an airtight container in the fridge before the flavor, texture and nutritional value degrade. If it is really off, you will know it as soon as you open the container.
Tips for Storing Smoothies
Some advice if you need to store a smoothie.
Firstly, use an airtight container in a fridge or freezer.
Don’t store it in your blender jug.
Most manufacturers caution against this as it may affect the performance of the blender and will cause the seal to degrade.
As the seal starts to fail, it will leak, and eventually you will have an interesting smoothie effect over you and your kitchen. Insulated jugs are fine if you want to drink your smoothie on the way to work.
You can freeze smoothies.
Do it immediately after making it,and remember to leave enough headroom in the container because it may expand as it freezes.
When you need it, let it thaw before using it, or re-blend it when it is half thawed.
In terms of lifespan, a reasonable rule of thumb is 48 hours in a fridge and a few months in a freezer.