The blending principle of Italian Coffee (Espresso) course on how to use Italian mocha coffee maker

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To explore the relationship between coffee machine pressure, coffee grinding thickness, temperature and time on the quality of coffee drinks.

Expresso

"espresso" is the Italian equivalent of "express" . , a coffee drink made immediately after guests click and finished quickly, is a beverage that guests must wait for.

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Pressure pot-Italian coffee maker

Pressure coffee brewing equipment invented in the early days of 1900

The pressure can reach 1.5 atmospheric pressure.

The temperature is much higher than 100C

In addition to extracting coffee soluble substances, also extruded a large number of insoluble substances under high pressure and mixed them into the liquid.

The severe bitterness and irritation of 

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Extraction temperature and taste of coffee

Strength degree

Slightly stronger

Moderate

Medium and weak

Weak

Acidity astringent taste

Viscosity irritation

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Espresso machine construction diagram

Supercharger (pump)

Heat exchanger

Extraction tank

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Espresso Coffee definition

is filled with about half full coffee liquid in a 50 cm thick magnetic cup (25Mel 35 c. C.)

is made under the following conditions:

The amount of coffee powder used by is 6.5 ±1.5g (5Mel 8g). The water temperature extracted by is 90 ±5C (85Mel 95 °C).

The pressure of extraction is 9 ±2 atmospheric pressure (7 Murray 11 atm)

The extraction time of is 30 ±5 seconds (25 Murray 35 seconds)

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coffee powder quantity

Particle size distribution of coffee powder

pressed powder (cake) pore

pressed powder shape

water quality

temperature Water temperature and Steam temperature

pressure

extraction time

pre-wetting pressed powder cake moistening

Machine Clean 7

Espresso coffee extraction factor

Coffee powder quantity

coffee contains different chemical components with different solubility.

With the progress of extraction time, different components dissolve out one by one.

The first component of to be dissolved and extracted is meta-acid.

The last soluble component of is bitter.

Astringent

The proper extraction amount of is that when the ingredients in coffee granules are extracted by 18Mel-22%, the composition that most people like can be achieved.

The concentration of coffee is 1.15% and 1.35%, which is considered by most people to be moderate.

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Coffee particle size and coffee taste

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bean grinder type Rollercutters

Conicalcutters Flatcutters

Particle size distribution of coffee powder microscopic image of coffee particle

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Flat cutters

raw bean quality maturity

hardness

defective bean

baking quality baking degree uniformity

moisture content bean grinder

Factors affecting particle size distribution

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The function of packing

reallocates the spatial configuration of particles changes porosity

Pressed powder (cake) pore

particle size and stack

particle size and porosity

Pressed powder shape

's traditional dual-dose powder cup is cylindrical, deep 12mm wide 60mm, depth / width ratio is

0.2 (= 12Universe 60)

if the depth-to-width ratio of the powder cup is less than 0.2 (shallow cup), the particles need to be fine to delay.

For a long extraction time, if it is greater than 0.2 (deep cup), the extraction pressure needs to be increased.

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affects functional sensation

other odors of tap water treated by chlorination

hard water

calcium ion deposition

Water quality

Extraction temperature and taste of coffee

Strength degree

Slightly stronger

Moderate

Medium and weak

Weak

Acidity astringent taste

Viscosity irritation

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Temperature

water temperature

powder cup handle temperature

steam temperature

in order to maintain the constant temperature of the machine, in the standby state, a small amount of steam will be sent to the cooking head to keep warm. The temperature of levying gas is so high that it usually overheats. Therefore, before putting on the handle, it is necessary to put water to cool down, and immediately after the handle is held, it should be washed to prevent steam filling, resulting in "scalding".

Pressure in the cooking process, the pressure is variable!

When dry powder, the pressure is small, under the impulse of water flow, the particles are redistributed, and the fine particles move to the bottom of the powder cup. The flow rate is faster.

After infiltration, the powder becomes colloid, the volume expands, the resistance increases, the pressure increases, and the flow velocity slows down.

After the extract leaves the powder cup, the volume decreases, the resistance decreases, and the flow rate increases.

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Crema formation

coffee oil components under high pressure, emulsification occurs, wrapped in air particles, shape

It's a bubble.

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The part of the tiger spot or leopard print is a broken cell wall.

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Correct extraction

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The influence factor of on flow rate powder quantity

porosity

cell contents

Extraction time

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Pre-wetting pressed powder cake moistening

Pre-infulsion first feed a small amount of water and stop for a few seconds to make the coffee powder moist and swollen, and then boil.

Start cooking.

provides a homogenized surface and provides homogenized extraction.

Machine cleanliness

coffee dirt should not be removed completely to reduce the smell of the new machine.