COFFEE PROCESSING TECHNOLOGY

Question 1

HARVESTING

Answer 1

Correct harvesting techniques produce of a high-quality final products
* Two harvesting methods:

Question 2

Two harvesting methods:

Answer 2

1. Selective picking 2. Strip picking

Question 3

2. Strip picking

Answer 3

• Pick only red and ripe cherries.
• Pickers rotate among the trees every 8 - 10 days.

Question 4

Advantages: Selective picking

Answer 4

Results in better quality of coffee beans

Question 5

Disadvantages: Selective picking

Answer 5

Labor intensive

Question 6

2. Strip picking

Answer 6

• Farmer strips entire branches of all cherries regardless on ripeness
• Can be done by machine or by hand.

Question 7

Immature harvesting (underripe coffee cherries)

Answer 7

• difficult to process & produce low quality product

Question 8

Overripe coffee -

Answer 8

Coffee cherries start fermenting causes flavor
deterioration

Question 9

Ø Advantage: Strip picking

Answer 9

Quicker than selective picking

Question 10

Ø Disadvantages: Strip picking

Answer 10

i) Mix green, red and overripe cherries – poor quality
ii) Higher amount of foreign matter

Question 11

Two common processing methods

Answer 11

i) Dry processing (natural)
ii) Wet processing (fermented and washed)

Question 12

DRY PROCESSING:

Answer 12

a low cost, traditional method of processing that produces a lower quality coffee than wet processing.

Question 13

Coffee cherries are dried under the sun until the coffee bean inside

Answer 13

Coffee cherries are dried under the sun until the coffee bean inside

Question 14

drying the beans with all layers intact:

Answer 14

Creating a
heavy mouthfeel, lower acidity , and more exotic, less consistent flavours.

Question 15

Solar drying

Answer 15

The coffee beans are sun drying on a clean dry floor or mats

Question 16

Problems of Solar drying :

Answer 16

i) Dust and dirt blown onto the coffee beans
ii) Rainy days

Question 17

HULLING

Answer 17

to remove the pericarp by hand using a pestle and mortar or in a
mechanical huller.

Question 18

CLEANING

Answer 18

cleaned by winnowing

Question 19

WET PROCESSING

Answer 19

1. The freshly harvested cherries are passed through a pulping machine where the skin and pulp is separated from the bean.
2. The cherry is squeezed in a pulping machine, removes the outer fleshly material (mesocarp and exocarp) leaving a bean covered in mucilage.
3. Mucilage is fermented and dispersed.
4. Bean is washed and dried.

Question 20

WET PROCESSING: Remove skin, pulp, parchment and silverskin

Answer 20

through pulping,
fermentation and washing process):

Question 21

WET PROCESSING: Leads to a bright, fruity, and
consistent flavour profile

Answer 21

with characteristics such as sweetness
and chocolate notes.

Question 22

Pulping

Answer 22

The removal of the outer red skin (exocarp) and the white fleshly
pulp (mesocarp) and the separation of the pulp and beans.

Question 23

The two most common pulpers and most suitable for small-scale
units are

Answer 23

1.Drum pulpers
2. Disc pulpers

Question 24

Drum pulpers

Answer 24

Involves a rotating drum with a punched sheet
surface and adjustable breast plate between the coffee cherries are pulped.

Question 25

The distance between the drum and the breast plate must be adjusted

Answer 25

so that the pulp is removed without the beans being damaged

Question 26

Disc Pulpers

Answer 26

The pulping operation takes place between the rubbing action of the bulbs on the disc and the lateral pulping bars called chop rails.

Question 27

The gap between the surface of the bulb and the chop rail can be adjusted to

Answer 27

allow for any clearance that may be required according to the variety and size of coffee fruit processed.

Question 28

Mucilage (silverskin) Removal

Answer 28

The amorphous gel of mucilage around the bean is removed by fermentation proses.

Question 29

Fermentation process (2-3 days): beans being placed in plastic buckets or tanks and left until

Answer 29

the mucilage and feasts bacteria work together to break down the mucilage.

Question 30

The beans are stirred occasionally and If the mucilage can be washed off

Answer 30

and the beans feel gritty rather than slippery, the beans are ready for drying.

Question 31

To prevent cracking, coffee beans are

Answer 31

dried slowly to 10% moisture content.

Question 32

Drying should take place immediately after fermentation

Answer 32

to prevent “off flavor” developing.

Question 33

After drying the coffee should be rested for

Answer 33

8 hours in a well- ventilated place.

Question 33

The hulled coffee is cleaned by

Answer 33

winnowing

Question 33

The thin parchment around the coffee is removed either

Answer 33

by hand, in a pestle and mortar or in a huller machine

Question 34

The roasting temperature is between

Answer 34

200oC -240oC

Question 35

The high roasting temperature cause a series of

Answer 35

physical and chemical changes in the seeds.

Question 35

Temperature 130oC – sucrose

Answer 35

caramelized, seeds begin to brown and swell

Question 35

Temperature 160oC – a series of

Answer 35

exothermic and endothermic reaction occur, the seeds become light brown, increase in volume and formation of aroma

Question 35

Temperature 190oC – Chemical reaction

Answer 35

responsible for the aroma and flavor of roasted coffee

Question 35

During the Maillard and Strecker reactions,

Answer 35

the light brown seeds change to black.

Question 36

Coffee roasted at higher temperatures for a shorter time - tend to exhibit

Answer 36

higher acidity, more soluble solids and a different volatile profile compared to those roasted for longer periods at lower temperatures

Question 36

Visual inspection continues to be the most accepted method to

Answer 36

determine the degree of roasting

Question 37

The most common roasters available for home/industrial use are drum roasters

Answer 37

Seeds are indirect contact with fire and hot surface

Question 38

Fluid bed roasters are preferred for industrial use because:

Answer 38

i) Faster ii) Allow better control of air temperature and speed inside the roasting chamber iii) Produce more homogeneous color

Question 39

Coffee is graded by

Answer 39

size, shape, odor, density and color.