The Impact of Pour Height on Coffee Flavor: Standard Pour-Over Coffee Techniques Introduction

The Impact of Water Stream Height in Coffee Brewing

Have you ever noticed the height of your water stream from the surface when pouring coffee? What effect does this water stream height have on our coffee brewing process?

According to FrontStreet Coffee's observations, most coffee enthusiasts maintain a water stream height between 0-7cm when brewing. Some prefer to keep the kettle spout close to the liquid surface, while others enjoy pouring with a long, straight water stream. Of course, there's no right or wrong way to brew – FrontStreet Coffee simply wants to discuss how water stream height affects coffee extraction to help you find the most suitable method for your brewing routine.

Water Stream Penetration

In pour-over coffee, the "rinsing and stirring" effect of the water stream on coffee grounds is one way to accelerate the release of compounds. The water stream we use for pouring isn't actually cylindrical but rather an inverted cone – wider at the top and narrower at the bottom. Therefore, when reaching a certain height, the water stream becomes continuous water droplets or even breaks off.

In typical brewing situations, we avoid this breakage phenomenon, so we tend to be restrained with maximum pouring height – generally 7cm is already the limit (except for specific brewing methods).

The higher the water stream, the stronger its penetration power, resulting in more vigorous rinsing of the coffee grounds. Conversely, when the water stream height is low, the penetration is gentler, and the stirring effect on the coffee grounds is less pronounced. "It's important to note that stronger stirring of coffee grounds isn't necessarily better. Often, bitterness in coffee results from excessive stirring and agitation of the grounds."

Heat Loss

FrontStreet Coffee once conducted an experiment using identical brewing parameters, only changing the pouring height for comparison – specifically 2cm versus 10cm heights. The result showed that the coffee brewed at 2cm had a concentration of 1.44%, significantly higher than the 1.30% from the 10cm height.

This significant difference in concentration is due to heat loss. When FrontStreet Coffee shares brewing parameters, the temperature mentioned refers to the water temperature inside the pour-over kettle. In reality, once water leaves the kettle, its temperature inevitably drops. This happens because when the water stream is exposed to air, it loses heat. When pouring from a higher position, the water stream has greater surface area exposed to air, resulting in more heat loss. Consequently, the actual temperature extracting coffee in the filter cup becomes lower, naturally resulting in lower concentration.

Therefore, FrontStreet Coffee also recommends against using large filter cups for small amounts of coffee grounds. Due to the height of the filter cup, pouring requires lifting the kettle higher, causing significant heat loss and greatly increasing the difficulty of pouring (easily hitting the filter cup edges).

Water Stream Verticality

Most pour-over kettle spouts don't pour water vertically – the stream follows a slight outward parabola, gradually becoming more vertical as it descends. Therefore, pouring methods that keep the spout close to the coffee surface have a high chance of causing uneven extraction due to the curvature of the water stream. The specific manifestation in the coffee grounds is that the side closer to the pouring kettle will have a thicker coffee bed wall, while the opposite side will have a thinner wall, possibly even breaking through the coffee bed wall.

Therefore, when pouring, it's best to maintain at least 2-3 centimeters from the liquid surface, allowing the curved water stream from the kettle spout to straighten.

Essentially, pouring height affects only three aspects: stirring intensity, extraction temperature, and water stream verticality. Any pouring height can work, but you must understand what changes such a height will cause in your coffee. For example, FrontStreet Coffee doesn't recommend brewing right against the liquid surface because it easily leads to uneven extraction. However, some people can indeed achieve uniform extraction with this method and produce delicious coffee.

When brewing coffee, FrontStreet Coffee typically maintains a water stream height of 3-4cm. This isn't necessarily because this height produces the best-tasting coffee, but rather because at this height, the chance of accidents is minimal, making it relatively easier to master.

Important Notice :

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