Digging thru my library, here's a few more relevant quotes on the general topic of processing, fermentation, casing and toppings:
Milton M. Sherman
"All About Tobacco"
"...the tobacco leaf is the chief source of flavor and aroma in any tobacco product, but because tobacco crops vary from year to year, flavoring supplements are necessary to help maintain a consistency in both taste and aroma."
"Virginia tobacco will accept very little of the casing sauce while Burley and Maryland tobacco can accept almost their own weight in fluids."
R.C. Hacker
"The Ultimate Pipe Book"
"...just as the curing process of briar is so crucial to the final smoking qualities of the pipe, so is the curing and fermentation process critical to the ultimate flavor that tobacco leaf will finally have in the bowl of your pipe..."
"Burley has an almost transparent flavor when used by itself, and this fact, combined with its unique ability to absorb the flavorings that are often added, makes it an excellent host and binding agent..."
Carl Ewha Jr.
"The Book of Pipes and Tobacco"
"...after the tobacco has been processed for aging it is packed in hogsheads under pressure and stored, sometimes for several years. During this period of aging, or fermentation, the tobacco undergoes chemical changes which reduce the nicotine and certain other substances in the leaf, resulting in a sweeter, mellower flavor..."
"...all of these straight Burleys are flavored, to a greater or lesser degree, by the manufacturer. except for the initial aroma, straight Burleys are pretty much the same, although their smoothness varies considerably depending on the grade of leaf used and how it is processed."
"A fine matured Virginia is somewhat analogous to an excellent Cognac. It possesses an alluring initial aroma that is neither light nor heavy and, although it is not so penetrating as the aroma of Cognac, it is similar in that both products remind one of a subtle mixture of rare fruit and spices in which no single ingredient overpowers the other."
"Subtle differences in flavor, intensity, body, and smoothness can be created from the skillful mixing and processing of these natural uncased tobaccos. English-Scottish mixtures have exceptional character. I would describe their flavor as bordering on a mixture of honey, nuts, delicate spices, and incense. While these tobaccos possess a definite natural sweetness, they would not be classified as sweet in the sense that fragrant tobaccos are sweet."
"The taste of Burley is rather bland, mainly because it has very little sugar in its chemical composition. Burley used in pipe tobacco is almost always flavored. The leaf has a good "drinking quality"..."
"...matters are further complicated by the fact that terms to describe the qualities of tobacco are loosely used within the industry. It is difficult in most instances to ascertain exactly what is in a can by reading the label."
