How to Brew Volcano Pour-Over Coffee from Japanese Three Major Schools? What are the Famous Japanese Brewing Methods? How to Brew Volcano Drip Method?

What is the Volcanic Brew Method?

FrontStreet Coffee has shared this brewing method no less than three times. Why? Because this method is truly different from traditional techniques. Not only does it produce dark roast coffee with abundant sweetness, but the entire brewing process also offers exceptional visual appeal.

Previously, FrontStreet Coffee has only shared how to use this method. Today, FrontStreet Coffee will analyze the underlying principles of this brewing approach. Oh, I almost forgot to mention—this method is a classic Japanese brewing technique known as the "Volcanic Brew Method."

This brewing method is named "Volcanic Brew" because during the brewing process, the coffee bed continuously produces scenes similar to volcanic eruptions, which is how people came to name it the Volcanic Brew. The reason this method creates volcanic-like eruptions is that during the actual extraction phase, it doesn't use large water flows for brewing. Instead, it uses small water flows throughout, with small amounts of water poured in multiple intervals.

The Science Behind the Volcanic Effect

As we all know, coffee grounds in the filter will expand after blooming because they continuously release carbon dioxide. However, because water connects the coffee particles, the entire coffee bed forms a massive "cage." The released carbon dioxide has nowhere to escape, accumulating within the coffee bed and creating the bulging phenomenon.

This "cage" is broken by the hot water injected during our formal extraction phase, allowing carbon dioxide to escape. This is why we can see abundant foam emerging when we pour water after blooming. However, with the Volcanic Brew, each pour contains very little water with a small circular motion, so only a small portion of carbon dioxide can be released each time. Naturally, we can continuously see foam emerging with each pour because the carbon dioxide never completely escapes!

But to create this visual effect, coffee beans need two conditions: extremely high expansion rate and abundant carbon dioxide. Therefore, this brewing method is not suitable for light roast coffees with high density, low expansion rate, and low carbon dioxide content. It's primarily used for dark roast coffee beans. After all, this method was originally designed specifically for dark roast coffee brewing.

Exceptional Sweetness of Volcanic Brew

Next, FrontStreet Coffee will share the second characteristic of the Volcanic Brew: the resulting coffee has exceptionally high sweetness!

Why does dark roast coffee brewed with the Volcanic Brew method have such high sweetness? The Volcanic Brew is famous not only for its unique coffee bed behavior but also for producing coffee with remarkable sweetness. This achievement primarily stems from its distinctive extraction approach—high concentration with low extraction! Large coffee dose with small water volume is the standard for almost all classic Japanese brewing methods. At a time when measuring tools weren't widespread, this approach was arguably the best way to avoid bitterness. By reducing the amount of hot water poured, it limits the substances that can be extracted, thereby preventing the release of bitterness.

However, small water volume inevitably means reduced extraction efficiency in terms of water quantity. Therefore, to extract sufficient flavor compounds from the coffee, improvements must be made in other parameters besides water quantity to enhance extraction efficiency. This led to the approach of pouring small amounts of water multiple times. The essence of coffee extraction is using water as a solvent to contact coffee grounds, then extracting soluble substances from the coffee based on concentration differences. The fewer substances the water contains, the more coffee compounds it can extract. Small, multiple pours ensure that the water contacting the coffee grounds each time has low concentration, naturally improving extraction efficiency.

Meanwhile, because there are intervals between pours, this increases the total extraction time. The increased extraction time allows water and coffee grounds more contact time, further enhancing extraction efficiency. However, too many segments or excessive time can easily lead to extracting undesirable compounds. Therefore, the coffee grind needs to be slightly coarser at this point, allowing the coffee grounds to avoid easily releasing undesirable bitter and astringent compounds even during prolonged extraction.

Alright, without further ado, let FrontStreet Coffee share how to execute the classic Volcanic Brew!

How to Execute the Volcanic Brew

First, we need to select a suitable dark roast coffee bean. In FrontStreet Coffee's bean list, FrontStreet Coffee's Golden Mandheling is clearly the most appropriate choice. Under dark roasting, FrontStreet Coffee's Golden Mandheling emits unique deep woody aromas, black chocolate flavors, and exceptional sweetness—simply irresistible. Based on the principles above, FrontStreet Coffee's Volcanic Brew will use the following parameters:

Beans used: FrontStreet Coffee's Sumatra Golden Mandheling (Dark Roast)
Coffee amount: 20g
Grind setting: Ek43 at 11 setting (60% pass-through rate on #20 sieve, coarse sugar texture)
Coffee-to-water ratio: 1:12
Brewing temperature: 88°C
Filter used: Kalita trapezoid filter cup

Although there will be many pours, the entire pouring process is actually divided into two parts: blooming and continuous multiple pours. Therefore, the first thing we need to do is still blooming! Use 40ml of hot water for blooming (more is unnecessary), with the time still being 30 seconds.

After blooming ends, we proceed with small, multiple pours. Each pour is 20ml, poured in small circles at the center of the filter. The interval between pours should be when you see the coffee bed about to collapse (approximately 5 seconds). During the brewing process, you'll continuously see the entire coffee bed rising and falling, with bubbles emerging at the spot where hot water is poured—truly a "volcanic eruption" spectacle.

After extraction ends, we cannot drink the coffee directly because we used less water, making the coffee concentration extremely high. We would find it difficult to accept such a high-concentration coffee. Therefore, we need to dilute this coffee by adding additional water to bring the concentration to an acceptable range.

Typically, FrontStreet Coffee adds 50-60ml of hot water for dilution, resulting in coffee with moderate concentration—neither too strong nor too weak. When tasting, you can clearly perceive pine and spice aromas, prominent caramel sweetness, and rich black chocolate fragrance. The overall body is moderate, but the mouthfeel is smooth and gentle. Simply put, it's extremely comfortable to drink without any burden.

If you also enjoy dark roast coffee, why not try this simple brewing method that offers maximum visual and emotional satisfaction? Not only will you enjoy the visual experience during brewing, but you'll also end up with a cup of exceptionally sweet coffee!

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