How do you zoom out while in a Google map? I know how to zoom in, tap twice, but no way to zoom out.

Same way you zoom in/out on pictures, Safari and just about everywhere else.

Pinch/spread fingers to zoom in/out.

Also try 2 finger double tap and 3 finger double tap.

In addition to the finger pinch/spread... one finger double tap to zoom in, two finger single tap to zoom out on Maps.