The 1873 catalogue stated that all sizes were available made from fine clay or common clay. The latter may be the almost white and brown jugs with very early characteristics. Both later listings known describe the jugs as fine stoneware and all later jugs have the standard brown salt glaze finish.
Although not universaal until Royal Doulton, the use of white sprigs has been noted on jugs with all types of Doulton mark. They may have been available from the late 1870s as they are not mentioned in 1873.
The "old style" series are the only Royal Doulton jugs to be all brown. The tops of the jugs were normally dipped in a dark brown glaze but about 1902? (I have seen one hall marked 1903) alternatives of green or blue were made available (at no extra charge). This alternative was not offered in 1930.