Understanding Pour-Over Coffee Extraction Characteristics: Three Key Elements That Transform Your Brew's Flavor

Many coffee enthusiasts visit FrontStreet Coffee after reading our articles, often taking the opportunity to discuss various coffee brewing challenges they encounter, particularly regarding pour-over parameters. Once, a friend asked FrontStreet Coffee a thought-provoking question: with so many parameters affecting pour-over coffee, which one is actually the most important?

This friend posed this question because despite carefully following tutorials each time and contemplating how to brew a perfect cup of coffee, the resulting flavors seemed to vary each time, with whether it tasted good being purely a matter of luck. They wondered if there might be some crucial step going wrong. Taking this opportunity, FrontStreet Coffee would like to explore with everyone today which parameters determine coffee's flavor and which play the key role in extraction.

The Charm of Pour-Over Coffee: Change

Most of you have probably heard the saying "coffee is a mysterious art." For example, you must cut off the tail section at the end of brewing to avoid bitterness; you should wet the filter paper before adding coffee grounds; the bloom should form a dome; coffee tastes better when you change cups... When we don't understand the principles behind these operations, almost every action seems like "mysterious art." However, once we explore the logic behind them through a scientific lens, thoroughly understanding extraction and flavor, these mysteries naturally dissolve.

The same applies to parameters. Many details affect pour-over coffee, and each new bag of beans, each different filter cup, and each adjustment to variables can create a completely new brewing experience. Based on experience, brewing a delicious cup of coffee depends on six key factors: water temperature, coffee-to-water ratio, grind size, pouring technique, time, and water quality. Among these, the first four receive the most attention, as time is influenced by the first three, and water quality can be referenced in FrontStreet Coffee's previous articles. Now, let's break down each one with FrontStreet Coffee.

Water Temperature

If you ask whether water temperature is important for extraction, FrontStreet Coffee believes it's important but not critically so. As a tool for adjusting extraction speed, higher temperatures make it easier to extract soluble substances, but since too high temperatures can easily release bitterness from coffee, it's best to choose a conservative range. Generally, most coffee beans on the market are suitable for brewing with water at 86-93°C.

Based on FrontStreet Coffee's brewing experience, medium-light roast coffee beans that can withstand extraction can use 91-93°C, while dark roast beans that are more sensitive to extraction are recommended to use 86-89°C. Coffee with both acidity and bitterness can be brewed directly at 90°C.

But precisely because water temperature is an easy parameter to control and its effect on flavor is relatively easy to understand, many enthusiasts fall into a misconception: that a 1°C difference makes a huge impact. For example, a customer purchased a bag of Sidra coffee beans and brewed them at home following FrontStreet Coffee's recommendation (91°C), but found the aroma weak and bitterness prominent. They instinctively thought the temperature was too high, but after reducing it by 1°C and then 2°C, they found the taste remained the same. After some discussion, it turned out the real culprit was grinding too fine.

FrontStreet Coffee once conducted an experiment, finding that coffee brewed at 91°C and 93°C had very similar flavors. Although there were subtle differences in taste, without direct comparison, it's almost impossible to notice significant variations. Therefore, as long as you're not using temperatures that deviate significantly from FrontStreet Coffee's recommendations above, when coffee shows obvious abnormalities, we can confirm it's not the water temperature's fault—the issue likely lies with other parameters.

Coffee-to-Water Ratio

The coffee-to-water ratio refers to how much coffee grounds you use, then injecting the corresponding amount of hot water according to a fixed ratio. As the amount of water increases, more substances are extracted, increasing the extraction rate, but the coffee concentration becomes lower. Therefore, choosing a ratio is essentially about controlling both extraction rate and concentration within a range that makes for a comfortable drinking experience.

For example, FrontStreet Coffee's most commonly used ratio is 1:15, where 15 grams of coffee grounds correspond to 250g of water. Some enthusiasts find that coffee at this ratio has too concentrated flavors and high concentration. In this case, they can increase the water proportion to 1:16 or 1:17, meaning by increasing the water amount to maintain balanced taste while highlighting the coffee's aftertaste.

However, if the coffee concentration is moderate and there are no uncomfortable flavors, but the main issue is insufficient aroma richness, FrontStreet Coffee doesn't recommend adjusting by changing the coffee-to-water ratio parameter. Because once you deviate from the appropriate concentration, too much or too little water can easily lead to under-extraction or over-extraction.

Grind Size

Grind size is not only the number one challenge faced by countless beginners but also a major aspect of extraction theory. In fact, regardless of the coffee brewing method, grind size is of utmost importance. To achieve the right coffee flavor, we must ensure both appropriate grind particle size and relative uniformity of the grounds, allowing coffee to release substances evenly under hot water impact. Operationally, the former requires finding the right grind setting, while the latter demands good grinding quality from the grinder.

For example, some beginners use analogical methods to judge coarseness, adjusting their grinder settings according to the "fine sugar" standard provided by FrontStreet Coffee. But during coffee brewing, they discovered severe clogging, thinking they hadn't found the right grind setting. In reality, it was caused by poor grinding quality, because the final coffee bed looked like mud as shown in the picture below, and the time often exceeded 2 and a half minutes. There are two main solutions: either buy a tool to sift out some of the extremely fine particles, or directly switch to a grinder with better grinding quality.

Additionally, there's the more commonly concerned issue—particle size. Simply put, the finer the grind, the more easily the particles accumulate on the filter paper, increasing resistance to water flow, so drainage speed is slower, extraction time becomes longer, and the resulting coffee flavor will be more intense.

Because this parameter affects the total time change, baristas typically determine whether the grind setting is correct by combining extraction time and coffee flavor. It's quite simple: if time is less than 1 minute 40 seconds, with sharp acidity and thin taste, it indicates the particles are too coarse; if time exceeds 2 minutes 20 seconds, with bitterness and astringency, heavy and low tones, it might be ground too fine.

Pouring Technique

Pouring technique refers to the combination and arrangement of details such as water distribution, flow rate, and pouring path. When the previous parameters are already set within a reasonable range, the pouring technique can be seen as a means to maintain dynamic balance in the coffee.

Whether you use single pour, three-stage pour, four-six method, or the more challenging tornado brewing, uniform extraction is our primary goal—that is, achieving even water distribution. The simplest way to judge is to look at the coffee bed after brewing. For specific analysis, you can find answers in FrontStreet Coffee's article "Complete Guide to Pour-Over Coffee Beds!" published last week.

Compared to the previous visual parameters, pouring technique is more controlled by human factors, making it the biggest source of uncertainty. Therefore, if you're in the early stages of exploration and learning, FrontStreet Coffee recommends using more stable brewing methods, such as the three-stage pour. After all, this method allows you to brew any coffee bean as long as you master the water flow speed and circular motion, making it the "universal solution of the pour-over world."

Of course, pouring technique can also be a flexible parameter that helps us achieve more complete extraction.

For example, FrontStreet Coffee planned to brew Colombia's Big Navel using standard parameters (15g coffee grounds, 1:15 coffee-to-water ratio, 91°C, 80% grind sieving rate) with a three-stage pour (30ml, 95ml, 100ml).

But after completing the second pour, the coffee liquid had completely flowed into the lower server in less than 1 minute. To avoid insufficient extraction due to too short contact time between coffee and water, FrontStreet Coffee temporarily changed the pouring plan, splitting the remaining 100ml of hot water into two parts—50ml + 50ml—poured slowly in small circular motions. Finally, the time landed at 1 minute 55 seconds, and the coffee presented a full, juicy flavor.

Important Notice :

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