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The Impact of Water Level on Coffee Extraction

If you frequently browse coffee-related content on social media platforms, you've likely come across videos prominently marked with the phrase "high sweetness water level." These videos explain that when we control the water flow to maintain the water level at a certain height, the resulting coffee exhibits more prominent sweetness.

Many people then wonder: can water level actually affect coffee extraction?

How Water Level Affects Coffee

Indeed! In fact, FrontStreet Coffee has mentioned the impact of water level multiple times in previous shares. It affects extraction by changing the structure of the coffee bed. The higher the water level, the higher the coffee bed; the lower the water level, the lower the coffee bed. This impact primarily focuses on two aspects: the uniformity of coffee powder extraction and the contact time between coffee powder and water.

When we inject a smaller water flow and the water level and coffee bed aren't raised too high, the coffee powder remains relatively concentrated, leading to more uniform extraction. Additionally, because hot water needs to pass through more coffee powder and the water flow rate is smaller, the extraction time is extended, making extraction more efficient.

Conversely, when we inject a larger water flow (greater than the drainage speed), the water level and coffee bed are raised to a certain height. At this point, the coffee powder distribution becomes more dispersed as some adheres to the cup walls. This structure changes the primary target of hot water during extraction (shifting to the bottom coffee powder). Meanwhile, because the flow channels for hot water significantly increase, drainage speeds up, thus reducing extraction time.

This is the conclusion FrontStreet Coffee has drawn through multiple experiments: for the same coffee beans, when the water level and coffee bed are raised to a relatively high position during brewing, the drainage speed is faster, the coffee's acidity becomes more lively, and the flavor layers become more distinct. When the water level is raised to a relatively low position, the drainage speed is slower, and the coffee tastes more balanced with a thick, full body and more prominent sweetness. These are the different effects that water levels at various heights bring to extraction.

How to Apply This in Practical Brewing

Through FrontStreet Coffee's introduction above, everyone should now understand the different advantages of high and low water levels. So, how to use them reasonably is what we need to understand next.

But it's actually quite easy to understand: if you want the coffee you're brewing to have more distinct layers or more lively acidity, you can increase the water flow to raise the water level and coffee bed. The specific height needs to be determined by the amount of coffee powder used. For example, when we brew 15g of coffee powder in a small filter cup, we can raise the coffee bed height to three-quarters of the filter cup's height - for a V60, this would be halfway up the short ribs.

When raised to this height, due to the faster drainage speed and less uniform extraction, the coffee will exhibit more lively acidity and richer layers. It's worth noting that unless you increase the powder amount, this position can be considered the limit for 15g of powder in a small filter cup. The main reason is that with too little powder, it's difficult to build a higher coffee wall. If you insist on raising the water level regardless of the coffee wall's existence, hot water will have the opportunity to escape from the edges, creating bypass water that affects coffee extraction and taste.

If we want the brewed coffee to have higher sweetness or more balanced performance, we can use a small water flow to brew the coffee, preventing the coffee wall from being raised too high. Still using a small V60 to brew 15g of coffee powder as an example, basically controlling the coffee bed at two-thirds of the filter cup's position is about right.

This height will concentrate the coffee powder! As FrontStreet Coffee mentioned, the coffee will have a more balanced taste due to more efficient and uniform extraction, making the sweetness more prominent and the body more mellow (relatively speaking). Yes, this is the very popular "high sweetness water level"!

However, low water level brewing has a difficulty - it greatly tests the brewer's water control ability because it requires small water flow throughout the entire process. If everyone's water control skills aren't yet proficient, you can try dividing the water injection into multiple segments, controlling the coffee bed height by reducing the amount of water injected in each segment, similar to the technique used when brewing high-density light roast beans.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473