Medidas Físicas y Sensoriales -...
Transcript of Medidas Físicas y Sensoriales -...
28,000 estudiantes de pregrado,en 104 especialidades
6,600 estudiantes de posgrado
1 de 10 Campus universitarios en California, pero solo campus con ciencia de los Alimentos
Famoso por las bicicletas, y la sostenibilidad ambiental
Hay muchos hispanos y personas que hablan español
Lab 1 – Reverse Engineering a Drip Coffee Brewer
Lab 2 – Process Flow Diagram and Mass Balances for Coffee
Lab 3 – The pH of Coffee and Chemical Reactions
Lab 4 – Measuring the Energy Used to Make Coffee
Lab 5 – Mass Transfer and Flux during Brewing
Lab 6 – Coffee as a Colloidal Fluid and the Effect of Filtration
Lab 7 – First Design Trials: Optimizing Strength & Extraction
Lab 8 – Second Design Trials: Scaling Up to 1 Liter of Coffee
Lab 9 – Design Competition and Blind Taste Panel
An
alys
isD
esig
n
The Design of Coffee: An Introduction to Chemical Engineering
3 units: Lecture – 1 hour; laboratory – 2 hours. Non-mathematicalintroduction to how chemical engineers think, as elucidated bythe process of roasting and brewing coffee. Qualitative overviewof the basic principles of engineering analysis and design.Corresponding laboratory experiments testing the effect of designchoices on the sensory qualities of coffee.
2013 2014 2015 2016
Coffee Lab renovated, begins serving 500 students / quarter
UC Davis Coffee Initiative established
Design of CoffeeFreshmen Seminar
(18 students)
Establishment of the Coffee Center
Peet’s Coffee provides a
founding gift
2017
Donations from severalmore forward-thinking
companies and individuals from the
coffee industry…
2018
Green Bean Storage
Laboratory
Brewing & Espresso
Laboratory
Patio
PilotRoastery
6000 sq. ft. of space, dedicated as a home for coffee science research
and advanced education
BehmorStudent Space
JosumaMeeting
Space
Metabolomics& Nutrition
ZivkovicSlupsky
Sociology &Cultural Studies
Biltekoff Kyle TaylorBio-Ag Engineering
Donis-Gonzalez
Fan
Bottling &Food Safety
Bamforth Harris
Sensory & Consumer Science
Guinard Heymann
Genetics
Cantu Medrano
Chemistry
Barile
German Lebrilla
Mitchell
Plant Science
van Deynzes Brown
Aerosol Science
Wexler Zhang
Microbiology
Marco Mills Boundy-Mills
Sustainability& Efficiency
Schladow Simmons Spang
AgriculturalEconomics
Boucher Kiesel Sexton
Chemical Engineering
Boulton
Kuhl Runnebaum
Ristenpart
Greenwood
Law, IP, &Regulatory
ScowTomich
Earnest Earl Lockhart
ca. 1940 (Antarctica)
ca. 1960 (Coffee Brewing Institute)
http://www.scanews.coffee/2013/10/04/the-coffee-brewing-institute/
Nice historical article by Emma Sage regarding the CBI:
Two Key Metrics for Every Brew
Total Dissolved Solids (TDS)
How much soluble coffee
is actually in our drink
(also known as “strength”)
Percent Extraction (PE)
How much of the soluble coffee
was removed from the grounds
(also known as “yield”)
≈ 20%
≈ 1.5%
The Coffee Brewing Control Chart
(Lockhart, 1960s)
The numbers in the chart can be derived from mass balance arguments(lots of equations!)
Ted Lingle, ca. 1990
http://www.scanews.coffee/2013/10/04/the-way-we-were-specialty-coffees-first-decade/
Nice historical article by Donald Schoenholt re early SCA :
Ted Lingle et al.
Number 1 book sold by SCA
The Coffee Brewing Control Chart Needs Technical Updating
Standard brew charts are not
temperature corrected for density
Difficult to account for mass
loss via CO2 offgassing
Implicit assumption about 𝑅𝑎𝑏𝑠 inaccurate values
• Chart is based on
percolators! (Mr.
Coffee was invented
in the 1970s)
Chart pre-dates drip brewers
(Mr. Coffee was invented in the 1970s)
• Chart is based on percolators! (Mr.
Coffee was invented in the 1970s)
Chart ignores chemical reactions
Chart conflates sensory descriptive
with hedonic sensory judgements
(these are not the same!)
Sharp dividing lines falsely imply minor
changes portend huge differences
The Coffee Brewing Control Chart Needs Sensory Updating
Sensory data was based on 1950s housewives
(not representative today)
Discrimination Testing• Triangle tests
• Treatments 2x2 design
• Four total treatments
• Flat Bottom, Conical
• Two grind settings – Mahlkönig Guatemala
• Setting 3 (finer) and Setting 4 (coarse)
• 6 total pairs were compared
• 45 participants, each tasting all 6 in random order
Flat Bottom
Grind 4
Conical
Grind 4
Flat Bottom
Grind 3
Conical
Grind 3
SIG - 25/45
SIG – 23/45
SIG – 33/45
P < 0.001
SIG – 22/45
P=0.048
X X
p = 0.004
NS – 18/45
P = 0.292
p = 0.024
NS – 15/45
P = 0.394
Main conclusion:
Basket shape matters more than grind size!
Descriptive AnalysisOverview:
1. Define your product set
2. Convene a panel of judges
3. Attribute generation• Judges are blind to the product
treatments
• Presented the Coffee Lexicon/
Wheel
• Panel leader remains impartial
• All vocab is panel generated
4. Vocabulary alignment through
reference standards
Aroma IngredientFloral/ Chamomile Chamomile tea, dry
Smoke/ Acrid Wright’s Liquid Smoke MesquiteFlavorBerry Private Selection Triple Berry Preserves
Dried Fruit Mixture of Sun-Maid Prunes and Prune JuiceRaisin Sun-Maid RaisinsCitrus Fresh lemon juice
Whiskey Jack Daniel’s Tennessee WhiskeyDark Green/ Veg equal parts juice green bean : spinach : asparagus
Hay-Like McCormick Parsley FlakesMusty/Dusty Kretschmer Wheat Germ
Earthy Miracle-Gro Potting Mix soilTobacco Camel cigarettes (Turkish and Domestic blend)
Brown Roast C&H Pure Cane Sugar, Golden BrownGrain/ Malt Equal parts Rice Chex, Wheaties and Quaker Quick Oats
Brown Spice Equal parts cinnamon : nutmeg : cloveHazlenut Roast hazelnut oilAlmond Raw almond sliversMolasas Grandma’s Original Molasses, unsulphured, in water
Chocolate Toll House semi-sweet morselsCocoa Hershey’s Cocoa Powder Natural Unsweetened, in waterWood popsicle sticks
Burnt Wood/ Ash wood ashRubber rubber bands
Principal Component Analysis of Descriptive
Lr = Light Roast
Dr = Dark Roast
Co = Conical
Ba = Flat Bottom
3 = Grind 3
5 = Grind 5
Roast
Geometry
Grind
The sensory data clearly show the basket geometry makes a difference.
The key question is: ¿por qué?
Absorption ratio – Analogy with Paper Towels
Paper towels absorb water…but only a finite amount.
The more paper towels you use, the more water you absorb:
𝑅𝑎𝑏𝑠 = mass of absorbedwater
mass of dry paper towels
Dry coffee grounds also absorb water… and only a finite amount
𝑅𝑎𝑏𝑠 = mass of absorbed water
mass of dry coffee grounds
Did differences in absorption ratio affect the brew?
Short answer: Almost definitely yes!
Flat Bottom Conical
3 5 3 5
1.50
1.75
2.00
2.25
G rind S etting
reta
ine
d w
ate
r (g
)/ d
ry c
off
ee
(g
)
DarkL ight
Flat Bottom Conical
3 5 3 5
1.50
1.75
2.00
2.25
G rind S etting
reta
ine
d w
ate
r (g
)/ d
ry c
off
ee
(g
)
DarkL ight
𝑃𝐸 = 𝑇𝐷𝑆 × (𝑅𝑏𝑟𝑒𝑤 − 𝑅𝑎𝑏𝑠)
Conclusions (flat vs. conical matters a lot!)
In progress:Brew profiles and fractionation (physical measurements)Core sampling for extraction yield, correlate with tempHedonic (liking) sampling of consumers (flat vs. conical)Most important: Mapping entire brewing parameter space
?
Many thanks to our sponsors!
Acknowledgements
Finally, muchas gracias to Anacafé for the invitation!
Dr. Scott Frost Mackenzie Batali Prof. Jean-Xavier Guinard
Importancia Sensorial de la Extracción del Café en la Cadena de ConsumoProf. William Ristenpart, UC Davis Coffee Center
Raúl Roda, Paradigma / Onyx Coffee
Juan Luis Alvarado, Anacafé