We’ve asked you to transfer your starter to a new jar on day 15 to ensure that you (and we) can get a clear visual of maximum height and bubble production. After you’ve submitted your data and pictures on day 15, you can maintain and use the starter(s) however you like!  (For this project, we are focusing on the first 15 days, only.) The easiest thing to do, will be to maintain only a single starter; although, if you grew starters using different flours, you may choose to keep them, to maintain any distinct characteristics.