What factors affect espresso extraction?

Coffee Extraction Basics: How to Adjust Espresso Flavor Step-by-Step?

In this week's video from Marid Coffee, Ahmed Al-Hani simply explains how espresso flavor changes based on several factors:

Pressure, water temperature, grind size, extraction time, water quality, and the pre-infusion stage.

If you've ever noticed that your coffee is:

• Too acidic

• Or excessively bitter

• Or weak, as if it's not coffee at all

The problem is likely not with the beans, but with extraction.

Watch the video and review the practical explanation, then refer back to this article as a written reference to help you revise.

Coffee extraction is the process by which ground coffee interacts with water, where components from the coffee dissolve sequentially:

• Initially, acids are extracted.

• Then sugars and delicious oils.

• Finally, bitter compounds emerge.

If extraction is insufficient → the taste becomes acidic and weak.
If extraction is excessive → the taste becomes bitter and burnt.
The goal is to reach the golden zone that produces a balanced cup of coffee.

In the video, Ahmed focused on these main factors:

1. Pressure

2. Water temperature

3. Grind size

4. Extraction time (and weight)

5. Water quality

6. The Pre-Infusion stage

Let's review them in detail.

Espresso is prepared with high water pressure passing through ground coffee, and the ideal pressure is about 9 bars.
Lower pressure leads to under-extraction and a weak flavor, while higher pressure causes fast water flow and channel formation within the coffee, resulting in a burnt and weak taste simultaneously.
Remember that pressure is related to grind size; the coarser the grind, the faster the water flows, and the finer the grind, the higher the pressure or the water flow stops.
For more details and a practical understanding, watch Ahmed Al-Hani's video on the Marid Coffee channel.

Water temperature is one of the most important factors in coffee extraction, with the ideal temperature ranging between 90 and 96 degrees Celsius.
Some baristas prefer 92°, others 94°, depending on the type of beans and roast level.

If the temperature is low (85° or less):

• Extraction will be incomplete.

• Acidity will dominate, and the flavor will be weak.

And if the temperature is too high:

• Bitterness and a burnt taste will appear.

Understanding water temperature and its effect on espresso flavor is the secret to preparing a balanced and delicious cup.

Grind size determines the extraction duration for espresso. We need a fine grind, similar to powdered sugar, for:

• Appropriate water resistance

• 9 bars of pressure inside the puck

Coarse Grind:

• Water passes quickly

• Fast shot (10–15 seconds)

• Acidic and light flavor without crema (under-extraction)

Very Fine Grind:

• Very slow water flow

• Shot might take a minute

• Bitter taste and over-extraction

Marid's Rule:

If the shot is faster than 20 seconds → we fine-tune the grind.
If it's slower than 35 seconds → we coarsen the grind.

Extraction time balances the amount of coffee, grind size, pressure, and temperature. The traditional recipe:

• 18 grams of coffee

• 36 grams of espresso

• Within 25–35 seconds

If the shot is fast → under-extraction, fine-tune the grind or increase the coffee.
If it's slow → over-extraction, coarsen the grind or reduce the coffee.

Observe the color of the espresso flow: brown/golden at first, and if it becomes very light yellow, it indicates excessive bitterness and should be stopped.

This is a step to moisten the coffee with a small amount of water at low pressure before full pressure.

It helps to:

1. Absorb water evenly

2. Reduce channel formation within the coffee

3. Gently release carbon dioxide

The result: balanced extraction, better crema, and cleaner taste.

Example: 5–8 seconds at low pressure, then full pressure at 9 bars, which is included in the extraction time.

How much coffee do you put compared to water?

• The common ratio is 1:15 or 1:16 (e.g., 15 grams of water for every 1 gram of coffee). The coffee-to-water ratio plays a crucial role in extracting flavors.

• The ratio varies according to your taste and the strength of coffee you prefer.

• Always monitor time, as it is the best indicator of a problem.

• Adjust the grind first before changing any other factors.

• Ensure consistent pressure and temperature in the coffee machine.

• Use appropriate water before blaming the quality of the coffee beans.

Try adjusting the temperature between 92 and 94 degrees Celsius and notice the difference in coffee flavor.

To prepare a perfect espresso, you need:
Controlled pressure, suitable temperature, precise grind, appropriate time, pure water, and a refined recipe.

All these factors work together to give you an espresso shot that satisfies you before it satisfies your customer.

If you want to understand these factors practically with clear examples, don't miss:

Ahmed El Hani's espresso extraction video on Marid Coffee's channel.

And discover how a simple adjustment can change the taste of your cup entirely.

Discover the world of specialty coffee with Marid Coffee — passion, quality, and perfection in every cup.