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After roasting the coffee, coffee needs to be
consumed. If you would like to do this somewhere besides the
place where it was roasted, you have to transport and store it.
If it is left exposed to the air, coffee will lose its freshness
and aroma within 10 - 14 days or so. Carbon dioxide, produced during the
roasting process, de-gases from
the beans, taking with it the volatile aromas and flavors within
the bean. The "trick", then, is to keep the carbon
dioxide from leaving the beans. Packaging is the answer, and
storage is the sub-answer:
Vacuum
Packaging - All of the air is sucked out of the tins
or packets of coffee. The packets are then hermetically
sealed. Without oxygen, the coffee will stay fresh much
longer. Of course, when the air is sucked out, so is the
carbon dioxide, so a lot of flavor is lost.
One-Way
Valve Bags - Freshly roasted coffee is placed into a
bag that has a valve that allows pressure to escape, but
allows nothing to come in. If the bag is flushed with an
inert gas such as nitrogen and/or carbon dioxide before
closing, then, as the atmosphere initially in the bag is
expelled through the beans through de-gassing, there will
remain virtually nothing to age the bean. Since every
pound of coffee beans produces about 10 quarts of gases,
you can see how any air that might have been
left would be forced out. This method will allow the
coffee to remain fresh for months, if not years.
The
Compression Method - The coffee is packed, under
pressure, with an inert gas. The beans remain under gas
pressure all the time. This has two advantages:
(1) Shelf life of three years or longer. The
CO2 in the beans cannot come out, as it is
constantly under equalizing pressure. Because of this, the
volatile aromas tend to become fixed to the the fatty
substances that coat the cell wall, thereby producing fats
that can be emulsified, imparting a wonderfully delicious
aroma and flavor to an espresso, in particular. In fact,
there is at least one company in Italy that specializes in
this method of hermetically sealing espresso beans in metal
containers and storing them for six months before selling them. . . and such a coffee it makes!!
Last updated
Saturday, April 05, 2008
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