HomeRoast Digest


Topic: documentation to support the fact that coffee (3 msgs / 226 lines)
1) From: miKe mcKoffee
Leave an open bag of potato chips sitting on the counter for a month or two.
Now munch a couple. Yuck, they're stale! But where's the documentation!
Scientifically prove they are in fact stale! No thanks, none needed. Same
for coffee, just taste it.
Tomes have been written about coffee chemistry if you really want to
research it. I even recall reading about different specific chemical changes
occurring. But it's not important to me and so don't have the references
fixed in the mind for recall, taste is all I care about.
IF someone else like's the taste of stale coffee, oh well. I have no need to
scientifically prove they have bad taste!
Kona Kurmudgeon miKe mcKoffee
www.NorwestCoffee.com
URL to Rosto mods, FrankenFormer, some recipes etc:http://www.mckoffee.com/Ultimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.
Pacific Northwest Gathering VIIhttp://themeyers.org/HomeRoast/">http://home.comcast.net/~mckona/PNWGVII.htmSweet Maria's List - Searchable Archiveshttp://themeyers.org/HomeRoast/
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2) From: Dean De Crisce
Lynne, posted below are some abstracts regarding coffee and 'shelf life'
that they might be interested in. Involves progressive degredation as a
result of oxidation. Here goes...
Dean De Crisce
Coffee Freshness Alteration of Roasted Coffee Beans and Ground
Coffee in the Presence of Oxygen and under Protective
Conditions
L. POISSON, P. KOCH, J. KERLER
Nestle Product Technology Center Orbe, Nestec LTD, CH-1350 Orbe, Switzerland
SUMMARY
The alteration of coffee freshness in roasted coffee beans as well as roast
and ground coffee
(R&G) was assessed by using two complementary flavour isolation techniques
(SPME and
SPE) for the quantification of volatile freshness and oxidation markers. It
was shown that
rapid degradation of freshness markers as well as formation of oxidation
markers occurs as
soon as the R&G coffee gets in contact with oxygen. The whole coffee beans
also do not
provide an adequate protection against quality alteration. Our quantitative
data clearly
revealed that the oxidative reactions are just delayed. Best protection of
coffee freshness
throughout shelf life was only achieved when R&G coffee was stored in single
portions filled
under inert atmosphere at low residual oxygen level.
Influence of the Storage Temperature on the Colombian Coffee Brew Quality
M. PÉREZ-MARTÍNEZ, P. ÁLVAREZ-VIDAURRE, R. MALETA, M.P. DE PEÑA, C.=
 CID
Department of Food Science and Technology, and Toxicology, University of
Navarra,
Irunlarrea 1, E-31008 Pamplona, Spain
SUMMARY
The evolution of typical coffee compounds, such us caffeine and
trigonelline, and
hidroxycinnamic acids and their degradation products (i.e. 4-vinylguaiacol),
and coffee brew
sensory quality throughout the time as influenced by refrigeration
temperature (4 ºC vs 25 ºC)
has been studied. High losses of odour intensity and total volatiles during
the first storage
days were occurred. An acceptable odour quality (fresh and not rancid) was
maintained until 7
and 15 storage days in 25 ºC and 4 ºC coffee brews, respectively. Howev=
er,
taste quality was
maintained longer than odour. Traditionally, pH 4.8 was assumed as the limit
of acceptability
for coffee (Pangborn, 1982; Dalla Rosa et al., 1986). But, pH was maintained
at 4.9 after 15
days at 4 °C, while sensory characteristics (odour and acid/sour taste) w=
ere
unacceptable.
Consequently, pH should not be the unique criterion of coffee brew
acceptability. Caffeine
and trigonelline concentrations were maintained along the time. An initial
increase of 5-CQA
followed by almost constant concentrations in both coffee brews was
observed. There was a
maximum peak of caffeic acid at 7 days and 20 days in coffee brews stored at
25 ºC and 4 ºC,
respectively. Furthermore, higher 4-vinylguaiacol decrease in coffee brews
stored at 25 ºC
than in those at 4 ºC was observed. In conclusion, coffee brews stored at=
 4
ºC could have
longer shelf-life than those at 25 ºC. Moreover, the storage temperature
influenced on the
evolution of some typical coffee compounds and their degradation products.
Modeling the Secondary Shelf Life of Ground Roasted Coffee
AbstractFull Text HTMLHi-Res PDF[161 KB]Monica Anese,* Lara Manzocco, and
Maria Cristina Nicoli
Dipartimento di Scienze degli Alimenti, University of Udine, Via Marangoni
97, 33100 Udine, Italy
J. Agric. Food Chem., 2006, 54 (15), pp 5571–5576 DOI: 10.1021/jf060204k
Publication Date (Web): June 27, 2006
Copyright (c) 2006 American Chemical Society
*  To whom correspondence should be addressed. Tel:  +39 0432 590721. Fax:
+39 0432 590719.
E-mail:  monica.anese
Abstract: This work was addressed to study the secondary shelf life of
ground roasted coffee.
To this purpose, fresh dark-roasted ground coffee samples were equilibrated
at increasing water
activity (aw) values up to 0.44 and stored at 30 °C for up to 1 month. To
simulate home storage
conditions, the headspace atmosphere was periodically perturbed by opening
for a short time and
then closing the packaging. The changes of some chemical and physicochemical
indexes of coffee
staling were studied, and sensory analysis was carried out to determine the
end point of coffee
acceptability. The results showed that the volatile compounds in the
headspace are representative
indexes of the quality depletion of roasted ground coffee during home usage.
The sensory and
instrumental results were used to develop a mathematical model allowing to
simply and quickly
calculate the secondary shelf life of coffee on the basis of its aw value at
a given temperature.
Coffee brew shelf life modelling by integration of acceptability and quality
data
Lara Manzoccoa and Corrado Lagaziob, ,
aDipartimento di Scienze degli Alimenti, University of Udine, Via Sondrio 2,
33100 Udine, Italy
bDipartimento di Scienze Statistiche, University of Udine, Via Treppo 18,
33100 Udine, Italy
Received 17 January 2008;  revised 13 May 2008;  accepted 24 June 2008.
Available online 1 July 2008.
Abstract
A methodology for the development of shelf life models predicting consumer
acceptability of coffee
brew on the basis of simple and easily detectable quality indices was
proposed. Coffee brew was
assessed during storage for consumer acceptability using both acceptability
scoring methodology and
evaluation of consumer rejection by survival analysis. Samples were also
analysed for hydrogen ion
concentration and intensity of sensory attributes (acid, off-flavour and
bitter) by a trained sensory
panel. Hydrogen ion concentration and sourness resulted to be the indices
best correlating with the
percentage of consumer rejecting the product during storage. Mathematical
functions predicting hydrogen
ion concentration and sourness as a function of the risk of consumer
rejection were defined. These
equations provided information to assist companies in choosing acceptance
limits and were integrated
with classic shelf life kinetic approach to produce shelf life models
accounting for consumer response.
Due to lower uncertainty of hydrogen ion concentration data as compared to
sourness sensory data, only
the former resulted to be a useful indicator of coffee brew shelf life.
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3) From: raymanowen
The documentation for the bag of chips, the jar of organic peanut or almond
butter or pecans would be the dated sales receipts.
Old buttered popcorn or the pecans are kind of tough to artificially
preserve, so might make a good A-B comparison. Check with some of
your octogenarian or nonagenarian friends to see if they haven't an old
container of stale or rancid foodstuff in the back of the pantry they'd
trade you  in the interest of research.
Absent the documentation, your test subjects can form their own conclusions.
We do so all the time. A trip to McDonalds just before they switch to their
lunch menu should remove any doubts, otherwise the sauce pan or microwave
are your friends. Reheat coffee that has sat out cold and been re heated a
few times.
Better yet, get a percolator at a thrift store. Brew a weak pot of Foulgers
using grounds from the Ancianos' lost stash. Do several cycles of Unplug it
and let it cool; plug it back in...
They might like it, in which case you provide a set of illustrated
instructions in an old Steno notebook using your best MD Latin and
calligraphy. "Antique Roadshow coffee brewer with Original illustrated
instructions and ground coffee sample." Dutch Auction starts at $125.00 -ro
On Mon, Feb 16, 2009 at 9:41 PM, miKe mcKoffee  wrote:
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-- 
"When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Mighty
Wichita (ex- NYC Paramount) WurliTzer- 1976
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