Tienstra studied Gregorian chant at the conservatoires of Amsterdam and The Hague, the International Summer and Winter Courses of Gregorian chant at Essen (Germany), and completed PhD studies in Musicology at the Folkwang University in Essen with a magna cum laude dissertation on melodic variation in Northern Low Countries manuscripts.
Research of and practice with varied chant groups and repertoires have given him a deep insight in the full range of chant, both in research and practice - reflected in articles and books such as a Guide on chant interpretation and conducting.
In 2023, Tienstra unearthed the full medieval Office of St. Jeroen of Noordwijk, published through a critical performance edition.
In international context, Tienstra is passionate about helping researchers and performers interested in the liturgy and chant of the Low Countries.
Tienstra is magister cantus of the Schola Cantorum Amsterdam since 2020 (having before been cantor for seven years), director of the two ensembles of the Schola Gregoriana Noordwijk since 2008 and director/teacher of the Gregoriaanse Kring Amsterdam. From 2013-17, he led the Schola Cantorum Oegstgeest.
Full yearly cycle of Masses; the Divine Office (weekly Sunday Vespers and Matins for all the major celebrations); newly arranged liturgies (e.g. 'Our Lady of Sorrows' and 'Rosary services'); concerts (Gregorian Christmas Concerts, Codex Calixtinus, Hildegard of Bingen); courses, lectures and publications (particularly on Dutch manuscripts).