Srewsen was born at Strandmøllen, the son of paper manufacturer Christian Drewsen. His paternal family had come to Denmark from Hanover where they had been involved in manufacturing paper since 1692. Prominent cultural figures such as Knud Lyne Rahbek and Adam Oehlenschläger were frequent visitors to the home. The writer and translator Hans Guldberg Sveistrup was a house teacher. His friend, Conrad Malte-Brun, sought refuge at Strandmøllen when he had the flee the country in 1793. Drewsen was apprenticed to his father but was struck by the new ideas of the time and the revolution and planned to become an army officer and go into French military service. He did, however, change his minds after falling in love with Johanne Ophelia Rosing, a daughter of the actor Michael Rosing.
Farmer and agronomist
When Drewsen was married in 1898, his father gave him the agricultural estate Smidstrup some ten kilometres north of Strandmøllen. By studying German literature on farming, and consulting the most successful farmers in the area, the pastors in Gentofte and Kongens Lyngby, and the brothers Jean and Frédéric de Coninck at Frederikslund, he acquired a great knowledge about farming. He introduced new technology as well as new practices and crops. He became a member of the Royal Danish Society for Agriculture in 1812 where he became the editor and writer of several publications on farming. He received the society's silver medal for a work on crop rotation in 1813 and its gold medal for a work on cultivation of clover. He also published a nine-volume translation of Albrecht Thaer's works on agronomy. From 1819 to 1930, he served as one of the society's three presidents. Together with Jonas Collin, he was the founder of the Agricultural Society for Copenahgen County in 1818. In 1819, he went on a study trip to Germany. Rogether with Frédéric de Coninck and pastor Rønne, he was the publisher of the journal Landøkonomiske Tidender, which he later continued alone. His most important work on agronomy, Betragtninger, was published in 1834. In 1841 and 1842 he published some minor works on breeding of silk worms and cultication of mulberry trees. He was involved in a controversy with professor Oluf Christian Olufsen.
Drewsen inherited Strandmøllen in 1810. It developed into the largest paper mill in the country after he modernized it with the introduction of steam engines and a hydraulic press. A major expansion took place in 1830. Drewsen had a monopoly on delivery of paper to the state as well as to the National Bank and completely dominated the market for paper used for printing. In 1844, the company was ceded to his sons Christian and Michael Drewsen.
Politics
In 1834, he became a member of Roskilde Stænderforsamling and soon became a leading figure in the fight for better conditions for peasants. In the 1840s, he supported the liberal movement as well as the Danish movement in Sønderjylland. In 1846 he was one of the founders of Bondevennernes Selskab and became a member of its board but broke with it in 1848 when it left the liberal movement. In 1835, he was a co-founder of the Society for the Proper Use of the Freedom of the Press. He was a member of Folketinget in 1849-1850.
Personal life
Drewsen shared his times between Strandmøllen and an apartment in Copenhagen. In 1799-1804, it was located at Vestergade 32. In 1807-1811, it was located at Knabrostræde 12. In 1844, it was located at Ny Kongensgade 8. In 1845-1849, it was located at Kronprinsensgade 8. In 1850-1851, it was located at Store Kongensgade 62.
