Before Felberbauer's comprehensive and topical study on the 17th c. Schloss Forchtenstein hand grenades, published in two vols. of the German Journal of Weaponry (
Zeitschrift für historische Waffen- und Kostümkunde) in 2012 and 2014 (see post above), there have sadly only been two tentative aprroaches to the matter, both made by Heinz-Peter Mielke in the same
Zeitschrift, in 1980 (vol. 2, pp. 153f.) and 1982 (vol. 1, pp.64-66).
For those to whom German is not just an accumulation of hieroglyphs

, I attached scans.
The first essay is on 17th-18th c. glass hand grenades in the Swiss Landesmuseum Zurich, while the second is on clay hand grenades in general (Mielke called them ceramic weapons).
Best,
Michael