What Is Coffee Aroma?
http://buyorganiccoffee.org/1867/what-is-coffee-aroma/
Wake up and smell the coffee, the saying goes. The aroma of coffee entices us to drink our java but just what is coffee aroma? The tongue tastes sweet, bitter, salty and sour. The rest of what we call taste comes from aroma and coffee has lots of it. Coffeeresearch.org tells us all about coffee chemistry and coffee aroma.
Coffee aroma is responsible for all coffee flavor attributes other than the mouthfeel and sweet, salt, bitter, and sour taste attributes that are perceived by the tongue. Therefore, it might be said that coffee aroma is the most important attribute to specialty coffee. Even instant coffee has the components responsible for stimulation of our taste buds. The difference, however, is that instant coffee lacks most of the aromatic volatile compounds causing a dramatic decrease in the overall coffee flavor.
It seems like every year more and more aromatic chemical compounds are discovered in coffee. The count today is more than 800 of these. However we don’t experience most of these. The coffee aroma we experience is based on the following:
How strong is the aroma of the compound?
How much of the compound is in your coffee?
How receptive are you to that particular aroma? This is known as the odor threshold.
What compounds provide the most aromas and what aroma do we experience from them? These are the big four in descending order.
Furans: These compounds come from the breakdown of sugars in the coffee bean during roasting and result in a caramel-like aroma.
Pyrazines: These compounds are responsible for cereal, roasted, cracker, toast-like walnut aromas in coffee.
Pyrroles: The sweet, caramel-like and mushroom-like aromas in coffee can come from these compounds.
Thiophens: If your coffee has a meaty aroma it probably comes from the breakdown of amino acids and sulfur in these compounds.
6. Coffee aroma is responsible for all
coffee flavor attributes other than the
mouthfeel and sweet, salt, bitter, and
sour taste attributes that are perceived
by the tongue.
7. Therefore, it might be said that coffee
aroma is the most important attribute to
specialty coffee. Even instant coffee
has the components responsible for
stimulation of our taste buds.
8. The difference, however, is that instant
coffee lacks most of the aromatic
volatile compounds causing a dramatic
decrease in the overall coffee flavor.
9. It seems like every year more and more
aromatic chemical compounds are
discovered in coffee. The count today is
more than 800 of these.
10. However we don’t experience most of
these. The coffee aroma we experience
is based on the following:
11. How strong is the aroma of the
compound?
How much of the compound is in your
coffee?
How receptive are you to that particular
aroma? This is known as the odor
threshold.
12. What compounds provide the most
aromas and what aroma do we
experience from them? These are the
big four in descending order.
13. Furans: These compounds come from
the breakdown of sugars in the coffee
bean during roasting and result in a
caramel-like aroma.
14. Pyrazines: These compounds are
responsible for cereal, roasted, cracker,
toast-like walnut aromas in coffee.
15. Pyrroles: The sweet, caramel-like and
mushroom-like aromas in coffee can
come from these compounds.
16. Thiophens: If your coffee has a meaty
aroma it probably comes from the
breakdown of amino acids and sulfur in
these compounds.
17. These are complex chemical
compounds. For example, guaiacol
which gives coffee a phenolic and spicy
aroma has this chemical structure and
chemical names.
20. The aromatic compounds in coffee
provide the smell of the coffee and the
taste but many of these compounds are
also the antioxidants that make coffee
so healthy.
21. Recent research shows that organic
coffee antioxidants include chlorogenic
acid lactones and lipophilic
antioxidants. Chlorogenic acid lactones
and lipophilic antioxidants are capable
of protecting nerve cells when
challenged with hydrogen peroxide.
22. Scientific American has a cute video
entitled The Universe in a Cup of
Coffee in which it mentions several
compounds that provide the aroma in
coffee.
23. That rich coffee aroma rises from the
steam because roasting coffee beans
converts bitter chlorogenic acid into a
diverse set of compounds. Some smells
you’d expect-fruity, spicy, earthy,
vanilla-but there are a few surprises
(cabbage??).
24. And adding a splash of milk or sprinkle
of sugar sets off a chain of physical
reactions. Convection makes the cold
milk sink while the interactions between
milk and coffee molecules create the
milky swirls. Brownian motion also will
spontaneously mix the coffee over time,
no need for a stirrer.
25. Pyrazine gives coffee an earthy smell.
Methylpropanol is responsible for fruity
and spicy aromas. Vanillin gives us the
vanilla aroma in coffee. Methional is
responsible for any baked potato aroma
in your coffee.
26. . If your coffee has a bit of a cabbage
odor you can blame methanethiol.
27. It is in the roasting that most of these
compounds are created.
