What Are the Key Elements to Brewing Great Coffee? Introduction to Pour-Over Coffee Extraction Principles

FrontStreet Coffee believes that coffee extraction is a process of passing water through coffee grounds to dissolve and extract substances from the grounds, as well as a scientific principle that can be experimented with. When water comes into contact with coffee grounds, most water-soluble substances are released and merge with each other, thereby extracting various coffee flavors—whether perfect or not—and ultimately allowing a cup of coffee to be brewed.

Coffee extraction is a complex chemical change. Different parameters such as roast level, bean-to-powder ratio, extraction amount, and water quantity all become factors that alter coffee aroma. However, to brew any cup of coffee, the fusion of grounds and water is necessary. Perfect coffee extraction helps enhance the taster's sensory experience, making the penetration of water through coffee grounds a critical action affecting coffee extraction.

Generally, the first substances released during coffee extraction are coffee aroma and acidity. This is why as soon as water passes through the coffee bed, the air fills with rich coffee fragrance, while sweetness and bitterness emerge gradually in the middle to later stages. However, if over-extraction occurs (beyond the later extraction stage), it results in excessive bitterness and astringency, causing the final coffee flavor to become overly thick and hollow.

Additionally, if coffee particles are too fine, they are more prone to over-extraction (because the coffee particles are extracted quickly, and if water hasn't yet penetrated through, it becomes soaking). Conversely, if coffee particles are too coarse, they tend to under-extract (because when they haven't fully contacted with water, the water has already completely permeated through). Therefore, for different brewing methods, pairing appropriate coffee grind sizes with various parameters is necessary to perfectly interpret coffee extraction.

Important Parameters Affecting Coffee Extraction

Golden Cup Theory

According to the Golden Cup Theory of the Specialty Coffee Association of America (SCA), good coffee must meet these data conditions: coffee concentration between 1.15-1.45% and extraction rate between 18-22%.

Coffee Concentration

• Below 1.15%: Tastes too diluted, with flavors too weak
• Above 1.45%: Tastes too thick, with flavors too strong

Extraction Rate

• Below 18%: Excessive acidity, with too much sharp and uncomfortable sourness
• Above 22%: Obvious bitterness, with dry, astringent, and negative mouthfeel

Following the aforementioned data, we can find that the balance between coffee concentration and extracted substances is very important. If one aspect is too light, it will increase the proportion of the other, resulting in poor tasting experiences such as over-acidity or over-bitterness. Therefore, the water-to-coffee ratio has also become an important factor affecting extraction.

About Extraction

The longer the extraction time, the more suitable for coarsely ground coffee particles; conversely, the shorter the extraction time, the more fine grinding will be chosen. Precisely standardizing the extraction time can showcase the unique flavors of coffee, making the final tasting experience approach perfection.

• Longer extraction time: Suitable for coarser grind size, with a refreshing sweet and sour taste
• Medium extraction time: Suitable for medium grind size, with a balanced sweet taste
• Shorter extraction time: Suitable for finer grind size, with a rich, pure, slightly bitter taste

Next, FrontStreet Coffee will use the popular FrontStreet Coffee Emerald Estate Diamond Mountain sold on Taobao as an example to demonstrate in detail how to brew a pot of reasonably extracted coffee that highlights its caramel characteristics.

Considering that caramel notes are often related to characteristics such as richness, smoothness, and strong body, FrontStreet Coffee suggests that when setting up the brewing plan, the focus can be placed on three aspects: "lowering water pour points, minimizing disturbance of the coffee bed, and utilizing soaking," while appropriately extending the extraction time, with the aim of releasing more substances that reflect the aftertaste.

Brewing Parameters

• Coffee Beans: FrontStreet Coffee Emerald Estate · Diamond Mountain
• Coffee Amount: 15 grams
• Coffee-to-Water Ratio: 1:16
• Dripper: Ceramic Wave Dripper
• Water Temperature: 88-89°C
• Grind Size: Fine sugar/EK43s setting 10
• Pouring Technique: Four-stage method

In the first stage, FrontStreet Coffee still uses a small stream of water to pour 30g of hot water clockwise from the center outward and let it bloom for 30 seconds, allowing the coffee grounds to enter a degassing state. In the second stage, we first lower the kettle spout, then use a slightly larger stream of water to pour 80g at a height of about 2cm, also continuously circling from the center outward, being careful not to disturb the coffee bed, utilizing the wave dripper's soaking characteristics to allow full contact between hot water and coffee grounds.

When the coffee liquid in the wave dripper is almost finished dripping, approaching 1 minute 25 seconds, then pour the third stage of 80g of hot water with a small stream, remembering to maintain the same low water level as before, with the aim of allowing the sweet substances in the middle section to be released in an orderly manner.

The final stage doesn't require waiting for all the water to dry up, but when the liquid level drops to halfway, still use a small stream to pour the final 50g from the center, completing all pouring by approximately 1 minute 45 seconds. Finally, wait for all the coffee liquid to filter through, remove the wave dripper, and end the extraction at 2 minutes 13 seconds.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473