The Coffee Kits

The Science Behind Chemex Brewing: Understanding Extraction

Chemex coffee brewing has been a popular method for coffee enthusiasts for many years. The process involves using a special glass vessel and a thick paper filter to make a clean, crisp cup of coffee. However, the Chemex brewing process is not just about the equipment and technique but also about the science behind extraction.

What is Extraction?

Extraction is the process of removing the flavors and oils from the coffee beans and transferring them into the water. The goal of extraction is to achieve a balanced and flavorful cup of coffee. However, the process is not as simple as just mixing water and coffee grounds together.

Factors Affecting Extraction

Several factors can affect the extraction process, including grind size, water temperature, brew time, and coffee-to-water ratio. Let's take a closer look at each of these variables:

Grind Size:

The grind size of the coffee beans is a critical factor in the extraction process. The finer the grind, the more surface area the coffee beans have, and the faster the extraction will occur. However, if the grind is too fine, it can lead to over-extraction and a bitter taste. On the other hand, if the grind is too coarse, the extraction will be too slow, resulting in a weak and under-extracted cup of coffee.

Water Temperature:

The water temperature is also crucial in the extraction process. The ideal water temperature for coffee brewing is between 195-205℉. If the water is too hot, it can lead to over-extraction, resulting in a burnt and bitter taste. If the water is too cold, it can lead to under-extraction, resulting in a weak and sour taste.

Brew Time:

The brew time is the amount of time that the water and coffee grounds are in contact with each other. The ideal brew time for Chemex brewing is between 3-4 minutes. If the brew time is too short, the extraction will be incomplete, resulting in a weak and sour taste. If the brew time is too long, the extraction will be overdone, resulting in a bitter and burnt taste.

Coffee-to-Water Ratio:

The coffee-to-water ratio is the ratio of coffee grounds to water used in the brewing process. The ideal coffee-to-water ratio for Chemex brewing is 1:16. If the ratio is too high, the extraction will be too strong, resulting in a bitter taste. If the ratio is too low, the extraction will be too weak, resulting in a sour taste.

The Chemex Extraction Process

The Chemex brewing process involves using a special glass vessel and a thick paper filter. The filter helps to remove any impurities and oils from the coffee, resulting in a clean and crisp cup of coffee. Here is a step-by-step guide to the Chemex extraction process:

Step 1:

Boil water and let it cool for 30 seconds to 1 minute until it reaches the ideal temperature of 195-205℉.

Step 2:

Grind the coffee beans to a medium-coarse consistency.

Step 3:

Place the filter in the Chemex vessel and rinse it with hot water to remove any paper taste and preheat the vessel.

Step 4:

Discard the rinse water and add the coffee grounds to the filter.

Step 5:

Slowly pour the hot water over the coffee grounds in a circular motion, making sure to wet all of the coffee grounds evenly.

Step 6:

Allow the coffee to bloom for 30 seconds by letting the water and coffee grounds sit before continuing to pour.

Step 7:

Continue pouring the hot water over the coffee grounds in a circular motion until you reach the desired coffee-to-water ratio.

Step 8:

Let the coffee brew for 3-4 minutes.

Step 9:

Remove the filter and discard the used coffee grounds.

Conclusion

The Chemex brewing process is not just about the equipment and technique but also about the science behind extraction. By understanding the variables that affect extraction, you can achieve a balanced and flavorful cup of coffee. So, next time you brew a cup of coffee using the Chemex method, keep in mind the science behind extraction and enjoy a clean and crisp cup of coffee.