An interesting question from a pipe guide book from the 60s when blending one’s own pipe tobacco was not uncommon: Is it possible to mix exactly the same blend of pipe tobacco, time after time, so as to obtain an unvarying flavour and aroma for many years?
It is possible to mix exactly the same blend time after time, but chances are the flavour and aroma will show subtle variations with every mix. There are many reasons for this. The same type of pipe tobacco grown in different regions will have different tastes. Weather conditions will also affect the pipe tobacco flavour from year to year. In order to produce an exact replica of a particular blend, the pipe tobacco should be purchased from the same manufacturer and in the same cut. It should be carefully measured, mixed in exactly the same proportions, and at the same humidity. Also make sure that the age of the pipe tobacco is approximately the same.
Taken from a Question and Answer section in Weber’s Guide to Pipes and Pipe Tobacco. Thanks again.