After working as a pharmacist's assistant in Frankfurt am Main until 1842 and in Schaffhausen until 1844, Voelcker entered University of Göttingen where he studied chemistry under professor Friedrich Wöhler.

He went to Utrecht in 1846 to work as assistant to professor Gerardus Johannes Mulder where Voelcker studied the chemistry of animal and vegetable production.

Voelcker was recruited as consultant chemist to the Royal Bath and West of England Society by Sir Thomas Dyke Acland, 11th Baronet in about 1849.

[6] He was appointed consultant chemist to the Bath Royal Literary and Scientific Institution in 1855, a post he held until 1863, although he continued to maintain connections with the society.

He was well aware of agricultural economics, for, as he said any good analytical chemist can ascertain the exact amount of the different constituents of the manure, and, knowing the market price at which they can be.

Retrieved separately, he is enabled to calculate with tolerable accuracy its commercial value[4] He set up a private consulting practice in London in 1863; he provided advice in many fields including sewage, water and gas supply, river pollution, and agricultural holdings.