I know it sounds like a worn out cliché, but “a little
knowledge can be a dangerous thing.” A customer and his new sales person
were going through a coffee training program at our offices, and during the Q
& A period they had some good questions about the basics and even some of
the more technical aspects of coffee.
The exchange was going well when my customer said another
roaster – let’s call him “Roaster X” – had stated that gas flushing
was only a good idea when the coffee in question was Robusta, the lower
species of coffee. Higher grade Arabica coffees, according to the other
roaster, lose their taste under gas flushing.
A bit floored by this comment, I was intrigued to know how
one could possibly come up with the equivalent of “It’s only good to
refrigerate skim milk; whole milk should be left on the counter all week to
improve the taste.” Naturally I wanted to dispatch this idea post haste, but
figured for the sake of science a more elaborate explanation was in order
(also I didn’t want the new rep to leave with kooky ideas).
First off, gas flushing is the process by which nitrogen is
injected into each coffee bag before it is sealed by packaging machines. The
principle is simple. The air we breathe contains about 20% oxygen, which we
need to live, but is also a corrosive gas. It is responsible for turning the
white of an apple red, making bread go hard, and staling coffee. If the air in
the bag is displaced by an inert gas (nitrogen), then the coffee will stay
fresher longer — a lot longer.
The Heritage Coffee Companies gas flush their fractionally
packed coffees to prevent them from becoming prematurely stale. What “Roaster
X” was suggesting is that oxygen will affect one genus of coffee differently
than another, and indeed that the replacement gas, nitrogen, is detrimental to
Arabica coffee.
I reached for my copy of the Oxford English Dictionary and
read aloud the definition of nitrogen, the gas used in gas flushing. After the
usual stuff about the periodic table, and so on, came the part which noted
that nitrogen is about 80% of the air we breathe. What “Roaster X” didn’t
think about was that by not gas flushing coffee, you are still exposing it to
a gas compound that is fully 80% nitrogen — according to him the dreaded gas
to be avoided!
Nitrogen as an inert gas is ideal for prolonging the life
of food items and is not detrimental to the flavor of any food (unless, of
course, you like the taste of stale). Seeing the logic in the argument, my
client and his rep both felt better about the fact that all the restaurant and
OCS coffees they sell are gas flushed.
But why would someone try to convince them that gas
flushing was a bad idea? I felt satisfied that they would come to a logical
conclusion on that mystery as well. As we said our good-byes, I couldn’t
seem to shake the mental image of “Roaster X” in his back shop, roasting
up his coffee… wearing his tall pointy black hat with moons and stars all
over it…
