Heinrich C.J. Tietz matriculated in 1892 and that same year started studying at the South African College, Cape Town. In 1894 he won the College's gold medal as the best science student and the next year was awarded the Bachelor of Arts (BA) degree with honours in mathematics and the natural sciences by the University of the Cape of Good Hope. Around the middle of 1895 he was appointed assistant in the College's Department of Chemistry, under Professor P.D. Hahn*. He resigned in 1898 and went to Germany, where he continued his studies in chemistry at the University of Berlin and was awarded the degree Doctor of Philosophy (PhD). His thesis was entitled Ueber eine neue reaktion der alpha-beta-unes?ttigten Ketoxime (Berlin, 1902). After his return to South Africa the University of the Cape of Good Hope admitted him to its MA degree on the basis of his German qualification.
In October 1903 Tietz was appointed lecturer in chemistry and metallurgy at the South African College. Professor Hahn and he remained the only two permanent members of the Chemistry Department until Hahn's death in 1918. Tietz was in charge of the department when Hahn went on a year's leave during 1906-1907, during Hahn's illness in 1917, and after Hahn's death in March 1918.
Tietz was a member of the Cape Chemical Society and served on its council from 1910 to at least 1914. He became a life member of the South African Association for the Advancement of Science in 1903. Perhaps because of his heavy teaching load he found little time for research. At the joint meeting of the British and South African Associations for the Advancement of Science in 1905 he delivered a paper on "An important characteristic of Cape wines", which was included in the Addresses and papers... published after the meeting (Vol. 1, pp. 260-268). He reported, on the basis of 300 analyses, that Cape wines contain more sugar and less acid than the same varieties of European wines. That same year he became a member of the British Association. In 1904, 1913 and 1916 he was an examiner in various branches of chemistry for the BA and MA degrees of the University of the Cape of Good Hope.
When the South African College became the University of Cape Town in 1918 three new professors were appointed in the Chemistry Department. Tietz, who was then 45 years old, became professor of organic chemistry, a post he held until he retired in 1935 or 1936. The other two appointments were Edgar Newbery (physical chemistry) and H.G. Denham (inorganic chemistry). During this later part of his career Tietz again found little time for research. He has been described as an uninspired person (Phillips, 1993).