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Title:

Coffee

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... red 'cherry' Processing. Dry: sun dry cherries & remove pulp ... Each cherry contains 2 coffee seeds or beans. Raw Bean: light bluish grey colour. Torrefaction ... – PowerPoint PPT presentation

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Title: Coffee


1
Coffee
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  • Foods, Facts Fallacies
  • YSCN 0006

2
What is Coffee?
  • A brown drink?
  • A brown sweet drink?
  • A brown bitter drink?
  • A stimulant?

3
Where does coffee come from?
  • Product of the Coffee tree
  • Native of the African tropics
  • Coffea arabica from highlands of Ethiopia
  • Coffea robusta found in Uganda in 1895

4
Coffee Islam
  • Introduced to Arabia around 1000 AD
  • Followed the spread of Islam around the Middle
    East and Mediterranean

5
The spread of Coffee Drinking
  • 800? Used in Africa
  • 1200 Widespread in Arabia
  • 1500 Coffeehouses common in Turkey
  • 1600 Coffee introduced to Venice
  • 1650 Coffeehouses in London
  • 1670 First café in Paris
  • 1683 Siege of Vienna, coffee introduced
  • 1700 Dutch grow coffee in Holland

6
The spread of Coffee Growing
  • 1713 Gift of coffee tree to Louis XIV
  • 1720 Introduced to Martinique
  • 1730 Spread in Caribbean to Brazil
  • 1720 -1850 Coffee production dominated by Dutch
    plantations in Dutch East Indies
  • 1860 Arrival of coffee rust in the Asia
  • 1870 Spread of coffee growing in S. America
  • 1890 Columbia and Brazil become major coffee
    producers.

7
Coffee Rust
  • Under British rule Ceylon was found to have an
    ideal climate for coffee and by 1825 was
    intensively planted with coffee plantations.
  • 1870 Ceylon was largest coffee producer in the
    world exporting 50 million kg
  • By 1890 output was down to 5 million
  • By 1910 coffee production had ceased

8
Coffee Rust
  • Hemileia vastatrix
  • Fungal pathogen of leaves
  • Coffee non deciduous, perennial, frost free,
    intensive plantations, monoculture.
  • No effective fungicides
  • Plantations decimated
  • Reached Brazil in 1978
  • Modern control measures can limit spread

9
The Coffee Tree
  • Coffea arabica
  • Self fertile, tetraploid
  • Small tree to 5m in understorey of upland forests
    2,000m altitude near equator
  • In cultivation usually pruned to a bush
  • Frost sensitive, temperatures not too cold or too
    hot,

10
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11
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12
Fruiting
  • Produce flowers when 4 years old
  • Flowering coincides with onset of rainy season
  • Fruit ripen in 8 months
  • Produces bright red cherry

13
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14
Processing
  • Dry sun dry cherries remove pulp when brittle
  • Wet Pulp and ferment 1 day to degrade flesh,
    then dry and polish beans to remove seed coat.
  • Each cherry contains 2 coffee seeds or beans
  • Raw Bean light bluish grey colour

15
Torrefaction
  • Roasting, 180C,
  • rotating mesh drum over gas furnace.
  • Timing critical.
  • Light roast, 5 to 6 minutes
  • Medium roast, 8 to 10 minutes
  • Dark roast, 12 to 15 minutes
  • Longer time gives stronger more bitter flavour,
    darker colour due to more browning reactions,
    caramelisation.

16
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17
Caffeine
  • Pharmacologically active ingredient of coffee
    (and tea, cocoa cola)
  • CNS stimulant
  • Diuretic
  • Cardiac stimulant
  • Muscle relaxant

18
A Safe Drug
  • Does not create dependency
  • Toxicity above 200mg/kg body weight
  • (approx 50 x average consumption)
  • No carcinogenic effect in humans
  • Average levels 80mg per cup of coffee
  • Average consumption around 200mg per day

19
Pharmacological Action
  • Stimulant action mimics adrenaline
  • Interaction with ß adrenoreceptors
  • Reduces reaction time and speed of motor and
    mental tasks especially in fatigue.
  • Improves concentration, causes insomnia.
  • Habituation and withdrawal slight.

20
Other effects
  • Diuresis from relaxation of tubules in kidney
    increasing filtration rate.
  • Useful as bronchial muscle relaxant in asthma.
  • Increases heart contraction rate, can trigger
    arrhythmias.
  • Excess consumption (over 500mg per day) in
    pregnancy can affect placental blood flow.

21
Brewing Coffee
  • Hot water extraction
  • Must grind beans to powder to increase surface
    area for extraction extraction
  • Fine grind, thorough extraction, stronger coffee,
    sediments more readily.
  • Coarse grind, less rapid extraction, milder
    coffee, higher density.

22
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23
Temperature Pressure
  • Pot , direct mix of boiling water and ground
    coffee, ready pour in a few seconds.
  • Basic method for 1000 years.
  • Variants
  • Cafetiere with a filter to retain grounds.
  • Boiling water and coffee together
  • 1905 Espresso machines introduced in Italy use
    pressure generated by steam to force water
    through coffee on a filter plate.

24
Espresso
  • 1908 Drip coffee maker using filter and slow
    percolation of water at low pressure just below
    boiling point.
  • 1945 Piston operated high pressure espresso
    machine invented by Gaggia in Italy.
  • Espresso more efficient extraction also includes
    more bitter flavoured extractives.

25
Coffee Types
  • Variety used, eg Arabica or Robusta
  • Region grown, African, American,Caribbean,
  • Effect of environment, climate soil.
  • Roasting
  • Blending
  • Grinding

26
Instant Coffee
  • 1938 Nescafe introduced by Nestle
  • Freeze drying of coffee extract.
  • Removal of moisture at low temperature preserves
    aroma.
  • Produces soluble granules that dissolve readily

27
Decaffeinated Coffee
  • Removes caffeine, preserves other flavours
  • Liquid CO2 excellent solvent for caffeine but not
    other aroma and flavour compounds
  • Green beans are treated after heating with steam
    to aid extraction.

28
Where is it drunk?
  • Sweden 9 kg pca
  • United States 7 kg pca
  • Western Europe 4 kg pca
  • United Kingdom 2 kg pca
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