Family #B-854 in The Immigration of German Colonists to Denmark and Their Subsequent Emigration to Russia in the Years 1759-1766.
Family #Rus-14-25 in The Immigration of German Colonists to Denmark and Their Subsequent Emigration to Russia in the Years 1759-1766.
Family #34 in the 1775 Grimm census.
Family #61 in the 1798 Grimm census.
Johannes Kohler is listed with his parents and his wife Barbara Kaiser in Danish records. According to those records, his father was from Baden-Durlach. 
1775 Grimm Census 
The census doesn't tell us that Johann's first wife died, but their names are slightly different and their birth years slightly off. I am creating two profiles for them until I can confirm through other sources that they are actually the same person.
Johannes Kohler's son, Johannes, age 28, is listed as if he is the child of both parents. Usually the census will state if the child has a different mother than the spouse listed. The 1798 census treats the son as the product of Johannes Kohler and Anna Maria Kaiser Kohler, but he is listed in the 1775 census as the son of Johannes and Maria Barbara Kohler.
Have you taken a DNA test? If so, login to add it. If not, see our friends at Ancestry DNA.
Johannes is 30 degrees from Prince Philip, Duke of Edinburgh Mountbatten, 32 degrees from Grace de Monaco, 33 degrees from Henrik af Danmark, 46 degrees from Sālote Mafile’o Pilolevu Veiongo Tupou, 32 degrees from Liliu Loloku Walania Kamakaeha Liliuokalani Kapaakea, 34 degrees from Te Atairangikaahu Paki, 39 degrees from Bhumibol Adulyadej, 46 degrees from 慈禧 葉赫那拉, 26 degrees from Jan Sobieski and 37 degrees from Fionnuala O'Connor on our single family tree. Login to find your connection.