Master Degree in Coffee Economics and Science “Ernesto Illy” MASTER THESIS “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from washed and natural processed coffee” Student: Carlos Umanzor Tutors: Eliana Cossio (University of Udine) Lorenzo Del Terra (illycaffè) Ext. Tutors: Jorge Cardona (Zamorano) Academic Years 2016-2017
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Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from washed and natural processed coffee
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Master Degree in Coffee Economics and Science “Ernesto Illy”
MASTER THESIS
“Sensory characterization and analysis of tea infusions
from dry coffee cherry pulp “Cascara” from washed and natural processed coffee”
Student: Carlos Umanzor Tutors: Eliana Cossio (University of Udine) Lorenzo Del Terra (illycaffè)
Ext. Tutors:
Jorge Cardona (Zamorano)
Academic Years
2016-2017
Title of the Paragraph (ex. Abstract)
2
Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
DEDICATION
I would like to dedicate my Master thesis to the living memory of my father.
He was a coffee lover and had great passion for the work he did. He is my role
model and the person I admire the most in this world.
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
ABSTRACT
The cascara or dry coffee cherries tea is one trendy coffee derivative gaining
more and more attention from the hot beverage drinkers. Origin countries are
exporting a very small (but increasing) amount of cascara every year to small
roasters across the world.
Very few studies have been made regarding the cascara’s chemical, nutritional,
and sensorial components in order to compare them with other tea infusion
ingredients or coffee itself. It is known to have much less caffeine than other
tea beverages, a natural source of antioxidants, more tannins which can be
beneficial for health (Fonseca-Garcia et.al, 2014), but probably not quantified
and measured into the correct amounts for human consumption.
The starting point of this work was to gather samples of cascara, not only from
my country of origin, Honduras, but also from other Central American regions.
Since there are proven and significant differences amongst the coffee beans
grown in the signature areas of these countries, I would only expect there to be
a difference as well in the dried cherries.
The present investigation analyzed the dried cascara brew in the certified lab at
the Escuela Agricola Panamericana Zamorano in Honduras. The sensory
analysis lab was used to test the acceptance, discrimination capability and
preference of the two brews. Color and sugar contents were measured by
equipment to correlate mostly with the data taken by the panelists.
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
ACKNOWLEDGMENTS
I would like to thank sincerely those who contributed and supported me in this
project, especially my co-workers and friends at Molinos de Honduras who
supported meanwhile I was in Italy and helped me source all the material I
needed to work freely and uninterrupted.
Would like to thank my friends in COCAFELOL (Honduras) and Godoy’s
Gourmet coffee (Guatemala) for spending their time and providing me with
sufficient cascara to make all the possible tests and analysis.
To the Escuela Agricola Panamericana Zamorano, my Alma Mater, for
providing their laboratories and panelists and very kindly supporting and
externally counseling me into having everything I needed to carry on an
outstanding analysis.
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
CONTENTS
1. Chapter 1: What is Cascara
1.1. Main goals 6
1.2. General Introduction 6
1.3. Consumption methods 7
2. Chapter 2: Origins and Process
2.1. Introduction
2.1.1. Washed Cascara 8
2.1.2. Natural Process Cascara 8
2.2. Materials and Methods
2.2.1. Description of materials 9
2.2.2. Brewing methods 9
2.3. Results and discussion
2.3.1. Sensory panels 10
2.3.2. Color and sugar contents 13
3. Chapter 3: General Conclusions 16
4. Chapter 4: Considerations and future perspectives 17
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
Chapter 1: What is Cascara
The main goal of this chapter is to get a general idea of what the dry cherry
pulp or cascara is. Learn about its multiple functions and consumptions
methods for the food industry. It has received many names and has been
consumed in many countries for the past years before it became a trendy
beverage. To know what are the main brewing systems used and its extraction
methods.
General Introduction
Coffee pulp, a long time thought of as a waste product, an irrelevant and
unused sub product of many coffee farmers around the world. Most often
thought of only as an additional weight or a conversion factor used to calculate
the real earnings or profits from a farm.
The evolution of coffee pulp as a useful sub product was first stated as an
agronomical practice and fertilizing aid for producers. Many studies have
stated the benefits of using the pulp as compost, fertilizer for the farms, or as
filling component for animal nutrition (Murthy PS, Madhava Naidu M, 2012).
Coffee pulp was shown to reduce by 30% the costs of production of a dairy
farm by replacing up to 20% commercial concentrates with dried pulp.
Meaning that at the end of a period a pig would have consumed 50 kg less of
corn by this substitution (Rajkumar & Graziosi, 2005)
It is not new that cascara has been used for tea infusions in past years; it is a
very common drink in Yemen called Qishr, where most of the people think the
Cascara tea was born.
Looking at Cascara tea nowadays, many people have tried to track down where
does it come from, what are the health benefits, how much caffeine does it
contain, and how to brew it correctly. Very little scientific information is found
about cascara, since it is just recently being commercialized as a food based
product. It has found its way up a very niche market in specialty coffee shops
and roasters around the world. These coffee connoisseurs are the ones writing
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
blogs on their web pages and studying on their own the endless possibilities of
transforming these dried cherries into a consumable product.
It is no wonder now that cascara is not seen as a byproduct of coffee anymore
but as Sweet Maria’s says on their page it is a very intentional product, targeted
by many markets and specially prepared for consumers in many different ways,
from a hot beverage to a cooking ingredient in house kitchens and restaurants.
Consumption Methods
French Press: 20 grams of cascara for every 500 ml of water at 90°C. Pour over
and let it steep for 3-4 minutes before plunging.
Chemex: 20 grams of cascara for every 500 ml of water at 90°C. The only
difference is we don’t use a filter for cascara since it’s not a coffee like brew,
but more an extraction. The pour over of water is done over the cascara sitting
at the bottom of the Chemex and let is steep for 4 minutes before serving.
Chapter 2: Origins and Process
In Honduras the normal harvesting period, as in most of Central American
countries, begins in late October with the low land coffee farms and ends
around March or April depending on the altitude of the farms. All of the coffee
is handpicked by farmers and pickers hired for the season.
According to Alvaro Llobet Coffee research report regarding the 2015
Honduran crop, 16% of Honduran coffee production comes from technified
farms. 15% comes from semi-technified farms. 34% comes from traditional
farms. 19% are wild type producing farms. 6% are abandoned farms still
remaining from Roya outbreak and producers who couldn’t survive the crisis.
The remaining 10% are new plantings not yet in production. (Llobet, 2015)
Having mentioned the coffee farm structure above, with an estimated 270,000
Ha of planted coffee area (IHCAFE, 2009) we will focus on the technified and
semi technified farms for the coffee pulp recollection of our study. Having in
mind that in order to meet a certain level of optimal cherry quality, ideal for tea
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
infusion we should look for the best and well managed farms, from the trees
that were properly fertilized and managed by the producer to develop and
harvest the best quality coffee bean.
Washed process
The washed process is the most common way of processing coffee in our
countries. After the pickers have gone through the farm and selecting only the
ripe and red color cherries, they are transported to a wet milling facility.
A wet mill has several stations or steps that the cherry pulp has to go through
before it is separated from the bean. Ideally we want to select and sort the best
cherries that would give the best coffee beans, and therefore a good quality
pulp. The cherries are passed through a machine called depulper that is
responsible for separating the bean from the cherry. After this point the bean is
covered in mucilage, which is later dispatched to fermentation tanks where this
mucilage is removed from the bean, leaving what we call “wet parchment
coffee.
Focusing on the pulp that was separated by the depulper, this is collected and
dryed carefully in African solar beds.
Natural Process
Natural processed coffee pulp is quite different from washed process mainly
because the cherry skips the wet mill process.
After the coffee is harvested and only the red cherries are selected, they are
sundried in patios or African beds. The whole cherry undergoes an immediate
drying process along with the bean.
This process allows the bean to absorb most of the sugars enclosed in the
cherry as it dries up. This drying period is over until the bean reaches 11 – 12
% humidity and the cherry is totally dehydrated.
The following step is the separation of the bean from its husk. The cherry now
goes through a hulling machine responsible for removing the cherry from the
bean, without causing any damage to it. We now have a totally different
looking coffee pulp from our washed processed one, but fulfilling the same
function.
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
Our coffee pulp was collected from a cooperative in the western side of
Honduras called COCAFELOL (Cooperativa Cafetalera Ecologica La Labor).
The quality of the coffee was gourmet type, mainly from caturra, catuai, and
parainema plants with harvest periods from December to April.
The designated farms for the selection of the pulp were at an altitude of 1,150
to 1750 masl with an average annual temperature of 16 – 21°C. Soil
descriptions are Sandy loam soils, medium in organic matter, with medium
filtration capacity.
Materials and Methods
Description of materials
In order to maintain a homogeneous and practical method for brewing I used
the following instruments.
Gram scale
2 kettles
2 mini stoves
Purified water
1 french press
1 chemex
Transparent cups for affective sensory analysis
Black cups for discriminative sensory analysis
5 lb of washed processed coffee pulp
5 lb of natural processed coffee pulp
1 refractometer Atago Pal-1
There is not a specific and standardized way of brewing these infusions. There
are many methods that can be used to achieve this final product, from different
kind of brewing machines, different timings and proportions used, the addition
of other ingredients like cinnamon or sugar, or even coffee itself.
Out of all the possibilities that can be used it seemed that French press was the
most common, therefore for the purposes of this experiment we did all tests
using a French press method, using 20 grams of cascara for every 500 ml of
water at 90°C for both processes.
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
Results and Discussion
Sensory Panels
The sensory analysis was done in the Sensory Analysis laboratory of the
Escuela Agricola Panamericana Zamorano,located in Valle de Yeguare,
Honduras. Panels were mostly students from the University and most of them
had already taken the illy-coffee course from the recent partnership agreement
done by these two institutions.
For the acceptance sensory analysis the panelist were given two separate sheets
of paper for the two different cascara brews. The tests involved a Hedonic scale
of 9 points to measure the acceptance of different attributes of the product,
using “1” as extremely Dislike and “9” as extremely like (Lawless & Heymann
1999). The attributes to measure were Taste, color, sweetness and general
acceptance.
As seen in the table below, the results from 30 panelists were evaluated for the
washed processed cascara brew.
Table 1. Washed process cascara
Color Taste Sweetness General Acceptance
7.33 7.00 6.47 7.13
±1.35 ±1.64 ±1.91 ±1.76
Comparing these attributes in a single table gives us an idea of how acceptable
the product would be for a consumer in general terms.
We can interpret that the color, taste and sweetness of the brew range in a high
score, where it surpasses the 7 points for each attribute. Therefore giving it a
general acceptance of 7 over all samples.
The range between these attributes are very close to each other meaning that
panelists found a balance in the brew, and did not sense abrupt differences
when perceiving the main attributes of the infusion.
Also 30 panelists were evaluated for the natural processed cascara brew and
their results are shown in table 2.
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
Table 2. Natural process cascara
Color Taste Sweetness General Acceptance
5.73 5.50 5.23 5.80
±1.57 ±1.28 ±1.52 ±1.16
Natural process cascara brew found the same balance within their attributes in
the infusion. The ranges between the scores of each attribute were evaluated in
the same range, within the same punctuation. This means that the panelists
found a smooth and consistent brew throughout their evaluation.
Interesting to notice that if it is true that the components and attributes within
the same processes don’t differ significantly from each other. When compared
one process with the other we find that the panelists scored significantly lower
the natural processed cascara from the washed processed one. With this it only
states that attributes like color, taste and sweetness were evaluated in a slightly
lower range than the washed ones.
The discriminative sensory analysis consisted of 3 samples given to the panels.
One given sample was different from the other two and their role was to
identify and mark the sample they thought was different from the rest (Triangle
test). In this case sample #212 was natural processed cascara and sample #213
and #214 were washed processed cascara.
Table 3. Discriminative results from washed and natural process cascara
Sample # Natural (212) Washed(213) Washed(214)
# panels 28 2
Total % 93% 7%
As shown in table 3, panels could clearly identify the different sample and
were easily convinced that sample #212 was different from the rest. The cups
used for this experiment were completely black and the laboratory lights were
dimmed so the color differences were not obvious to the panel. Forcing and
ensuring the panelists were only using their taste sense.
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
This correlates with the previous acceptance sensory analysis were panels
(some of them not the same) evaluated different one sample from the other.
Giving us certainty there is sensorial differences between one another. We
should keep in mind this does not in any way proves one brew method is better
than the other or more liked. This is just merely a differentiation test in which
we analyze the panelist’s ability to differentiate one sample amongst the rest.
Once the individual acceptance analysis was done for each of the cascara
processes and the discrimination analysis proved that there are detectable
differences between samples (as we expected), a preference analysis was
carried out. This analysis compared directly one brew with the other and
panelists had to choose the sample they thought was best for them.
PL was the washed processed cascara (Pulpa Lavada) and PN was the natural
processed cascara (Pulpa Natural).
Table 4. Preference analysis. Washed vs Natural processed
cascara
Type of process PL PN
# panelists 17 13
Total
57% 43%
Table 4 shows us that panelists choose washed processed cascara (PL) over and
better than natural processed cascara (PN). This time they had the samples
served in transparent cups, where they could observe and analyze color, taste,
and sweetness of each brew.
Given the acceptance analysis scores of each one of the samples we can link
that panelists maintained their opinion to think that the washed processed
cascara has better liked attributes than natural cascara, hence their preference
shown in this analysis.
Physical analysis
Sugar content: While making the brews for each round of panelists and
making sure to follow and maintain a consistent brewing protocol, the sugar
contents of each brew process were measured.
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Carlos Umanzor
Master Thesis “Sensory characterization and analysis of tea infusions from dry coffee cherry pulp “Cascara” from
washed and natural processed coffee”
It came to my attention that using the portable refractometer Atago in every
brew of the different processes it tossed the same Brix degrees for each sample.
Natural processed cascara brew tossed a 0.6% Brix on the brews tested, while
washed processed brew tossed 1% brix content on each sample.
Alan Adler, the aeropress inventor and frequent lecturer at Stanford University
is a keen user of the same refractometer used in this study. In an online post for
coffee geek, he writes about how he has measured brix content for coffees and
came to conclude that a standard measurement is 1.5 Brix. This in correlation
with SCAA recommended 1.25 Total Dissolved Solids (TDS) for ordinary
coffees (SCAA cupping protocols).
Café imports on their web page study and publish a blog on a wet mill in Costa
Rica called Las Lajas. The family owned mill and farm specializes in honey-
processed coffee that is sold to Café Imports later on. As their way to ensure a
good quality bean, Francisca (farm owner) measured the Brix content on the
coffee cherry to determine the optimal time to harvest the cherry. It is said that
cherrys in their optimal time for picking can measure up to 21-22% Brix
content (Café Imports, Las Lajas – Cascara perla negra). This is clearly
concentrated sugars measured in that will fade as the bean absorbs part of this
moisture and sugar content when dried.
Color: Color was measured using L, a, b color scale. Hunter Lab describes
these components as L for Luminosity ranging from 100(white) to 0 (black).
The “a” component is responsible for red (a+) and green (a-) color, they don’t
have numerical limits but positive and negative signs. Same for “b” component
where yellow (+b) and blue (-b) have positive and negative signs. See figure 1
for matrix reference.
Table 5. Color analysis for washed and natural process cascara
TRT R G B L a* b* h croma Washed 54.7 26.5 23.05 13.47 13.53 8.32 31 16.00