Leffingwell has made available on-line, for free, an interesting book chapter that discusses tobacco leaf chemistry, and its changes during curing and aging.
To gain the most from this article, you need some background in chemistry. However, sprinkled throughout this 20 page document are easily understood graphs and tables, as well as very clear, simple statements, such as:
"The major Amadori compounds present tend to
show a gradual increase peaking at about 2 years and
then a decrease. During the same period, the amino
acid content of the tobaccos shows decreasing values
each year. Of course, it is also known that the flavor of
Virginia tobacco improves with aging, it rarely being
used for cigarettes prior to 12 to 14 months aging, and
preferably 18 to 24 months, which interestingly corresponds
quite well to these graphs. Amadori compounds
are also known to generate a number of
flavorful pyrazines and pyrroles on pyrolysis."
[emphasis mine]
Of course, the graphs on aging do not consider the changes from one month of kilning.
Bob
To gain the most from this article, you need some background in chemistry. However, sprinkled throughout this 20 page document are easily understood graphs and tables, as well as very clear, simple statements, such as:
"The major Amadori compounds present tend to
show a gradual increase peaking at about 2 years and
then a decrease. During the same period, the amino
acid content of the tobaccos shows decreasing values
each year. Of course, it is also known that the flavor of
Virginia tobacco improves with aging, it rarely being
used for cigarettes prior to 12 to 14 months aging, and
preferably 18 to 24 months, which interestingly corresponds
quite well to these graphs. Amadori compounds
are also known to generate a number of
flavorful pyrazines and pyrroles on pyrolysis."
[emphasis mine]
Some other graph highlights. You don't even need to know what they're talking about, but can just look at the time scale of the changes. They should be vaguely familiar.Leffingwell.com said:Chapter 8
leaf Chemistry
Basic Chemical Constituents of Tobacco Leaf and Differences among Tobacco Types
J.C. Leffingwell, Leffingwell and Associates, Canton, Georgia, USA
http://www.leffingwell.com/download/Leffingwell - Tobacco production chemistry and technology.pdf
Of course, the graphs on aging do not consider the changes from one month of kilning.
Bob