Introduction to Techniques for Extracting Sweetness in Pour-Over Coffee: A Detailed Guide to the Rao Spin Stirring Method by the Coffee Godfather

The Rao Spin: A Different Approach to Pour-Over Coffee

FrontStreet Coffee has previously analyzed many Japanese pour-over methods, all characterized by being "slow, gentle, and elegant." Today, however, FrontStreet Coffee would like to share a simple brewing method that embodies "brutalist aesthetics"—the "Rao Spin," which we'll translate as the "Rao-style rotation method."

The "Rao Spin" is named after Scott Rao's sharing. In one of his blog posts, he explicitly stated that this method was not his original creation, and the true inventor remains unknown. However, it gained widespread attention due to Rao's sharing, hence it became known as the "Rao Spin." "After all, Arabic numerals weren't invented by Arabs either."

This method is both remarkably straightforward and effective at brewing a delicious cup of coffee (though visually unappealing during the process). Whether elegant or rough, any method that produces a good cup of coffee is a good method. Behind this "brutalist" brewing approach lies a rather rigorous brewing logic. If you're still learning the basics of pour-over coffee, this method is worth exploring.

FrontStreet Coffee will now share some video clips from Scott Rao's YouTube channel to help everyone better understand this technique.

In the video, Rao first explains his views on filter cone materials and paper filter selection. In his opinion, resin material is the best choice because it doesn't get hot to the touch and helps retain more heat during coffee extraction.

For paper filter selection, he suggests soaking your filters in hot water for 10 minutes, then tasting the water to choose the filter that imparts the least flavor.

The Brewing Process

Following the standard procedure, first wet the filter paper and preheat the coffee equipment. He used 22g of Colombian Cauca coffee beans. He didn't specify the exact grind size, but FrontStreet Coffee, through observing the coffee bed state, inferred it belongs to the quite fine category, approximately at an 85% pass-through rate. The water temperature wasn't specified either, so combining the lack of specification with default water temperature usage, it's inferred that Rao likely uses 95-96°C temperatures.

First, Rao pours three times the coffee grounds' weight in water for blooming, approximately 60ml. Immediately after pouring, he takes out a small spoon to gently stir the coffee bed, aiming to allow the coffee grounds to fully absorb water for blooming. (Truly a blessing for those with unstable pouring techniques.)

The blooming phase lasts for 45 seconds, during which a significant amount of coffee liquid has already flowed into the lower server, though it achieves the purpose of complete blooming.

Next comes the main pouring phase, where water is poured directly to the target volume of 360ml. You can see the water flow is quite large, with the water column showing a significant angle, but Rao says this isn't problematic. (Another blessing for those with unstable pouring techniques.) However, Rao also indicates that the pouring should maintain a horizontal level, not moving up and down.

From a top-down view, the water level rises rapidly, and this phase of pouring mainly serves to stir and agitate the coffee grounds.

After pouring, he immediately takes out the cute little spoon to "scrape" around the edges, pushing coffee grounds stuck to the sides back into the water, achieving true "equal treatment for all, uniform extraction."

At approximately 1 minute and 45 seconds, when the liquid level drops to about halfway, hold the filter cone and gently shake it 2-3 times. The purpose remains the same: "equal treatment for all, uniform extraction" - getting all coffee grounds to the conical bottom, avoiding residual grounds adhering to the filter cone walls.

Rao specifically mentioned that shaking once or three times won't significantly affect the coffee's flavor, so don't worry about ruining the coffee if you accidentally shake too many times.

The rest is left to drip slowly to completion. As you can see, the final coffee bed is very flat, with no clogging现象.

The coffee brewed this way will have very uniform extraction and full flavors. However, as mentioned in FrontStreet Coffee's previous article, there's a risk of over-extraction, which primarily comes from the grind size.

From Rao's demonstration video, it's apparent that the coffee grounds are very fine yet don't cause clogging, suggesting they have undergone a process to remove fine particles. Additionally, this method has high requirements for grinder precision. For normal-priced hand grinders, to brew 20g of coffee grounds, you would need at least 30g of coffee beans (after sieving out both coarse and extremely fine particles).

This method also teaches us the importance of uniform extraction for coffee flavor. If you can't achieve uniform extraction indirectly, just do it directly (physically).

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