The scoby has a Best Before date at the top - this is what we advise is best for first use by.
When you brew you are feeding the scoby so therefore it can be used over and over again.
When it’s in the packet it’s not getting fed, this is why it has a shelf life date that it needs to be used before.
Activity will decrease if it’s not being used, with feeding it’s revived but if it’s not fed before a certain date then we will not guarantee that it will work.