When making celery juice it's best to just juice enough celery into juice that you can drink in one day.
Celery Juice usually stays fresh for 24 hours in the fridge but sometimes can last as long as 4 to 5 days but it's best to drink the celery juice within the same day you made the celery juice to have it be fresh tasting and to get the most of the health benefits from the celery juice.
The longer you leave the celery juice in the fridge after making it the less nutrients it has to provide you with so drink it within 1 to 2 days to get the most health benefits of it.