Espresso Brewing Secrets: Illustrated Guide to Complex Italian Coffee Machine Operations and Principles

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Espresso Coffee - Italian Espresso - Espresso Coffee

Espresso is the lifeblood of coffee addicts. The essential espresso machine in coffee shops is both complicated and professional to operate. Dear friends, FrontStreet Coffee brings you a comprehensive analysis of espresso machine operation, with the editor visualizing the steps so you can also make espresso at home (provided you first invest in a machine).

What is Espresso?

Espresso originally referred to a brewing method of Italian coffee, using high temperature and high pressure to quickly extract concentrated coffee. Later, it simply came to be called directly Espresso.

What are the characteristics of espresso?

The coffee oils emulsify under high temperature and pressure, encapsulating air and water. The upper layer has thick foam (Cream) and the lower layer has milky liquid, achieving:

• Increased viscosity: The emulsified liquid tastes thicker and richer
• Enhanced aroma: Coffee fats carry the coffee's fragrance
• Extended aftertaste: Leaving a lingering fragrance on the lips and teeth

What are the principles of delicious espresso?

According to the Specialty Coffee Association of America (SCAA), the various conditions are:

• Coffee powder amount: 14-18 grams
• Grind size: Pour-over grind 3.5, espresso grind 1
• Water temperature: 90-96 degrees Celsius
• Extraction pressure: 9-10 atmospheres
• Percolation time: 20-30 seconds
• Volume: 50-70 milliliters

Water temperature affects the formation of the upper crema. The higher the temperature, the wetter the crema.

Let's begin the brewing process

Dosing:

Purpose: Fill the ground coffee into the portafilter.

Technique: How much to fill requires experience, which is why we now have dosing grinders.

Leveling:

Purpose: Level the coffee grounds in the portafilter.

Technique: Slide your finger from the high point of the coffee to the low point. Finally, remember to brush off any residual coffee from the "ears" (locking mechanism) on both sides of the portafilter.

Tamping:

Purpose: Compress the fluffy coffee grounds firmly.

Technique: Hold the tamper like holding a trumpet lock, allowing your index finger and thumb to feel if you're pressing evenly to avoid one side being higher than the other. Now there are anti-mistake lines to prevent baristas from pressing too hard and flattening the coffee grounds.

Cleaning:

Purpose: Clean residual coffee from the previous brew in the filter housing and bottom tray.

This step is extremely important in barista competitions!!!

Technique: First press the brewing action to let the front water come out, then wipe away the flushed water with a clean cloth. The cloth should be placed on the small side dish, not on the bottom tray.

Extraction:

Purpose: Brew the coffee grounds with high temperature and high pressure to produce espresso.

Technique: When installing the portafilter, bend down to check the locking position to avoid spending too much time fiddling with it and making the leveled coffee uneven. The clanging sound of locking and unlocking sounds unprofessional.

Press the brewing button and start timing, then take a cup to prepare for receiving the espresso.

At this point, you can judge the success of this extraction:

• Uneven water flow from both sides: Uneven tamping or inconsistent density
• Dripping water flow: Tamping density too high or inconsistent
• Water flow too slow: Tamping too tight
• Water overflowing from sides: Tamping too full

When you see the water flow start to deviate, you can prepare to stop extraction. When white spots appear, you must stop extraction immediately. White spots are the product of over-extraction and affect the appearance of the final product.

Extraction Process:

Espresso from different extraction periods, from left to right shows the first coffee extracted to the last moment...

The first cup is the essence within 30 seconds - the best tasting part.

The last cup has been extracted until nothing is left, with very light color and watery taste.

But coffee sold outside usually packages all four cups together, making it look like a lot, but it wastes the beauty of the first cup, which is a pity.

Inspecting the Final Product:

• Upper crema: Different coffee beans will have different colors (golden, nut colors...), white spots...
• After brewing and standing for a while, it will disappear and dissolve back into the coffee.
• Lower coffee: Color, impurities...
• Coffee puck: Skirt shape, height, hardness...
• Skirt shape indicates insufficient tamping, causing the puck to retain too much water.

The above are the steps for brewing espresso using an Italian coffee machine base.

Detailed steps for espresso extraction - Common knowledge of Italian espresso

Important Notice :

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