Caspar Voght's library in Klein Flottbek consisted of around 3,800 volumes, 200 maps, and a number of copper engravings. He collected works on geography and history, horticulture and agriculture, the poor and imprisonment. Travel writing, books on the "beautiful art of speaking," and Voght's own treatises on welfare and agriculture were represented. He kept his mineral collection and physical instruments in glass cabinets.