 Since 2009 he teaches Ensemble/Improvisation and double bass at Hochschule für Musik Köln and at "Institut für Musik Osnabrück".In 1993 Gramss founded the group "Underkarl" with Frank Wingold (guitar), Lömsch Lehmann (saxophone), Dirk-Peter Kölsch (drums) and Nils Wogram (trombone), still active as of 2017.He played with Frank Gratkowski, Tatsuya Nakatani, Rudi Mahal, Marilyn Crispell, Fred Frith, Tom Cora, Elliott Sharp, Peter Kowald, Taylor Ho Bynum, Zeena Parkins, Peter Brötzmann, Robert Dick, Karl Berger, Axel Dörner, Hannes Bauer, Heinz von Cramer, Terry Jenoure, Marjana Sadowska.