We present a data logging concept, tool, and analyses to facilitate studies of everyday mobile touch keyboard use and free typing behaviour: 1) We propose a filtering concept to log typing without recording readable text and assess reactions to filters with a survey (N=349). 2) We release an Android keyboard app and backend that implement this concept. 3) Based on a three-week field study (N=30), we present the first analyses of keyboard use and typing biometrics on such free text typing data in the wild, including speed, postures, apps, auto correction, and word suggestions. We conclude that research on mobile keyboards benefits from observing free typing beyond the lab and discuss ideas for further studies.