Most packaged roasted beans
and grounds as sold in the USA do not preserve the aromas
and tastes developed at the time of roasting, which sensual
properties the consumer wants.
The reasons for this are
several, and their deficiencies are varied, as will be explained.
In order to know how far
packaged coffee tastes differ from that of freshly roasted
beans, one has to be able to distinguish fresh roast from
various stages of staleness. In other words, one needs an
objective scale on subjective taste impressions.
Because tasting is a subjective
testing method does not mean that a freshness scale cannot
be established. In fact such a scale can be made using a group
of qualified tasters.
The qualified tasters cannot
be “off the street”, they need to have a reasonable amount
of pertinent taste experiences in the coffee trade over at
least several years, and their judgments need to be in harmony
with the others by and large. This is not a place for mavericks
or people who have an agenda that biases their taste impressions,
and believe it there are people in the trade with biases of
various sorts.
Tasting “freshness” is of
course influenced by the green beans used, the type and degree
of roasting, the kind of grinding, and the time frame from
roasting to cupping, and the manner of cupping. For example,
on the latter point, I prefer to do taste comparisons on beverages
as they would be prepared in a cafe, not as many do like cupping
evaluations on green coffee purchases.
The different tastes from
different origins are diminished rapidly from the time of
roasting. Note that the easily differentiated tastes just
after roasting are not available to the consumer from his
packaged coffees. So offering a dozen, or more choices, does
not offer distinguishing tastes, which only are revealed “just”
after roasting, and constitutes a consumer fraud.
What is it chemically that
exists just after roasting, that does not survive packaging
and time?
This is a complex situation,
but can be illustrated as follows.
Most of the aromatic chemicals
are aldehydes, and they can be rapidly oxidized in air.
Just roasted coffee beans
when sealed in a chamber release their aromatics and carbon
dioxide gas within 3 days and the taste changes can be followed
by cupping each day.
The sealed chamber pressure
rises to about 30 psig or 2 atmospheres from atmospheric,
and if the chamber is highly evacuated initially to more than
l atm or more than l5 psig. Because in the USA, most roast
coffees are sold as grounds in evacuated thin walled metal
cans, the coffee industry in the l930’s, made a decision to
only use a 90% vacuum (2l x 0.1 = 2.l% oxygen) in can as a
practical packaging matter, which was not consistent with
retaining the most freshness possible, but was a compromise
favoring the cost of said vacuum can closing machinery and
their considered taste acceptance at that time.
In fact, these machines did
not attain 2 % oxygen, but realistically at best only delivered
3 % oxygen in the can. And as the years went by, and that
canning-evacuation machinery wore, 4% OXYGEN was not uncommon.
This vacuum canning machinery
was very expensive, as were the operating costs for the vacuum
pumps.
Of course, 3 to 4% oxygen
was better than 2l% oxygen, but as everyone knows, canned
R&G coffees never tasted like freshly roasted beans.
What everyone did not know
was that roasted coffee aromatics and the beans themselves
reacted with the oxygen residual in the can in hours.
Further, in the largest roasting,
grinding, packaging firms, there always was several hours,
holdup of the just roasted beans, before grinding, and indeed,
most processors held the just roasted beans overnight to degas
the carbon dioxide gas coming off, and usually in bins that
had air entering. Therefore, not only was CO 2 leaving simultaneously
with the desirable aromatics but also oxidation was occurring
in hours. This has been and is today the way roasted coffee
beans are processed. In other words, the roast beans and grounds
are undergoing noticeable aroma and taste degradation before
they are ever packaged.
It has been only since about
l980, when there occurred a large growth in the specialty
coffee business, where hundreds of local roasting operations
came into being, that the consumer was able to buy and taste
“just” roasted coffee beans, and a new yard stick in coffee
freshness started to be established.
This local roasting was accompanied
by the use of “valve” bags, which allowed the CO 2 gas to
leave the bag (with aromatics) while not allowing oxygen into
the bag.
Although in principle, this
appeared to offer an extension in roaster freshness, it’s
value was far less than claimed, because of two factors: l)
It did not take into account the amount of oxidation occurring
before packaging, and 2) It did not take into account the
level of oxygen left in the bag when it was sealed.
A small vacuum, like l0%
leaves over l8% oxygen in the bag, but the bag shrinks over
the beans, and gives a positive visual impression. The appearance
of the shrunken bag is not much different with a l5% vacuum
or a 90% vacuum, but the oxygen levels are quite different.
Unfortunately most roaster/packagers
don’t know this. They don’t own an
oxygen analyzer; hence, they do not know what their vacuum-bag
sealer is in fact accomplishing.
They are paying tens of thousands
of dollars on, e.g. nozzle evacuating and inert gas purging
machines and are getting very high oxygen residues in the
bag.
Interestingly enough, the
manufacturers and distributors of these machines don’t even
follow-up on the use of their machines, and I’ve seen bags
being sealed at l/2 Atm vacuum which is over l0% oxygen, as
a considered normal.
I’d like to point out two
important ways to preserve fresh roast aromas and tastes:
l) If the residual oxygen
in the valve bag is taken to less than l %, but preferably
down to a few tenths of l % oxygen, a better tasting coffee
with longer shelf life will occur. Note that even though we
are working in a small area like 0.l and say 3% oxygen, it
is this window that highly influences what kind of aroma and
taste will result in days & weeks. The current industry
goals of a l year shelf life in cans is a poor standard based
on a very low taste acceptance, by conditioned consumers in
a market based on low prices and not top fresh quality. The
marketing of valve bagged coffees, preferably in bean, has
some added advantages in that the time frame is less, possibly
2 to 3 months.
2) By placing freshly roasted
beans in a hermetically sealed container, can or bag, with
or w/o low oxygen packaging at less than -l0 F in a commercial
freezer, will stop the release of CO 2 gas as well as aromatics,
and stop any chemical reactions therein, and the fresh roast
flavor is largely preserved, as verified by taste tests. This
condition begs for selling the roasted beans out of freezers,
which is simply a marketing method not yet applied on a large
scale. From a quality preservation point, it has been proven
on a small scale. It is also the method to use when making
taste comparisons with aged and oxidized beans.
Machinery is available to
achieve such preservations today.
As consumers become educated
to the pleasures of freshness, those processors who deliver
that freshness will gain market share. If consumers remain
uneducated, they will simply buy the poorer tasting products
based on price, a 2 tier market.
Mike Sivetz
CLICK
HERE TO ORDER FRESHLY ROASTED COFFEE BEANS THAT HAVE BEEN
PROPERLY PACKAGED!
