Doing my first lager and am curious as to how you know if the Diacetyl is gone. I have read to take a gravity test after rest. How much should the gravity change from the OG to know if the rest has worked? Also I have read to take a taste but I am not sure what I am tasting for. Also should the diacetyl rest take place while still in the primary fermentor or after it has been racked to the secondary? My lager sits at 48 to 50 degrees F now and I plan to do the rest for 3 to 5 five days between 53-55 degrees F. Any information on this would be of much help. Happy Brewing, Chris.