From "Marijuana Botany" by Robert Connell Clarke

I am sure there are other links to this, but this one will do for now.

http://www.geocities.com/SunsetStrip...96/botany3.htm

f) Taste and Aroma - Taste and aroma are closely linked.
As our senses for differentiating taste and aroma are con-
nected, so are the sources of taste and aroma in Cannabis.
Aroma is produced primarily by aromatic terpenes pro-
duced as components of the resin secreted by glandular
trichomes on the surface of the calyxes and subtending
leaflets. When a floral cluster is squeezed, the resinous
heads of glandular trichomes rupture and the aromatic ter-
penes are exposed to the air. There is often a large differ-
ence between the aroma of fresh and dry floral clusters.
This is explained by the polymerization (joining together in
a chain) of many of the smaller molecules of aromatic ter-
penes to form different aromatic and nonaromatic terpene
polymers. This happens as Cannabis resins age and mature,
both while the plant is growing and while curing after har-
vest. Additional aromas may interfere with the primary
terpenoid components, such as ammonia gas and other
gaseous products given off by the curing, fermentation or
spoilage of the tissue (non-resin) portion of the floral
clusters.
A combination of at least twenty aromatic terpenes
(103 are known to occur in Cannabis) and other aromatic
compounds control the aroma of each plant. The produc-
tion of each aromatic compound may be influenced by
many genes; therefore, it is a complex matter to breed
Cannabis for aroma. Breeders of perfume roses often are
amazed at the complexity of the genetic control of aroma,
Each strain, however, has several characteristic aromas, and
these are occasionally transmitted to hybrid offspring such
that they resemble one or both parents in aroma. Many
times breeders complain that their strain has lost the de-
sired aromatic characteristics of the parental strains. Fixed
hybrid strains will develop a characteristic aroma that is
hereditary and often true-breeding. The cultivator with
preservation of a particular aroma as a goal can clone the
individual with a desired aroma in addition to breeding it.
This is good insurance in case the aroma is lost in the off-
spring by segregation and recombination of genes.
The aromas of fresh or dried clusters are sampled and
compared in such a way that they are separated to avoid
confusion. Each sample is placed in the corner of a twice-
folded, labeled piece of unscented writing paper at room
temperature (above 650). A light squeeze will release the
aromatic principles contained within the resin exuded by
the ruptured glandular trichome head. When sampling,
never squeeze a floral cluster directly, as the resins will ad-
here to the fingers and bias further sampling. The folded
paper conveniently holds the floral cluster, avoids confu-
sion during sampling, and contains the aromas as a glass
does in wine tasting.
Taste is easily sampled by loosely rolling dried floral
clusters in a cigarette paper and inhaling to draw a taste
across the tongue. Samples should be approximately the
same size.
Taste in Cannabis is divided into three categories
according to usage: the taste of the aromatic components
carried by air that passes over the Cannabis when it is in-
haled without being lighted; the taste of the smoke from
burning Cannabis; and the taste of Cannabis when it is con-
sumed orally. These three are separate entities.
The terpenes contained in a taste of unlighted Canna-
bis are the same as those sensed in the aroma, but perceived
through the sense of taste instead of smell. Orally ingested
Cannabis generally tastes bitter due to the vegetative plant
tissues, but the resin is characteristically spicy and hot,
somewhat like cinnamon or pepper. The taste of Cannabis
smoke is determined by the burning tissues and vaporizing
terpenes. These terpenes may not be detected in the aroma
and unlighted taste.
Biosynthetic relationships between terpenes and can-
nabinoids have been firmly established. Indeed, cannabi-
noids are synthesized within the plant from terpene
precursors. It is suspected that changes in aromatic ter-
pene levels parallel changes in cannabinoid levels during
maturation. As connections between aroma and psycho-
activity are uncovered, the breeder will be better able to
make field selections of prospective high-THC parents
without complicated analysis.


More to come...