A properly-maintained bin should not be producing this liquid except in the first few days when the moisture is settling out. This liquid is called "leachate" and it is the result of food waste breaking down and releasing water which leaches to the bottom of a worm bin.
This liquid is not worm tea or worm pee......worms do not urinate. :)
What we recommend is to leave the bottom completely detached for the first few days to allow any excess moisture to escape through the drawstring bottom. (Consider placing a tray below the Urban Worm Bag).
Once the bottom has stopped leaking any moisture, it is generally safe to put the bottom back on and and begin feeding food waste.
But moving forward, it's important to also add bedding to the waste at 1:1 or 2:1 ratio by volume.