As the Temperature Drops, How Can We Ensure Pour-Over Coffee Brewing Isn't Affected?

Today, Guangdong province has finally cooled down after being washed by the typhoon, truly stepping into autumn's climate. But did you know that this drop in temperature actually adds some difficulty to our coffee brewing process? If we're not careful, it can easily alter the final flavor profile of our coffee. So, as we enter the upcoming cold season, what extra details should we pay attention to when brewing coffee?

1. Increase Brewing Water Temperature

Actually, the water temperature we inject when brewing coffee is not the same as the originally set temperature inside the kettle. What does this mean? For example, if we set our brewing water temperature at 92°C - that's the temperature inside the brewing kettle - but when it flows out from the spout, it starts to cool down because it contacts the air outside the kettle. By the time it lands on the coffee grounds, the water temperature drops to around 87°C.

However, due to the recent significant drop in temperature, the air that comes into contact with hot water naturally becomes colder, causing the poured hot water to lose more temperature before reaching the coffee grounds. If we continue brewing with our original water temperature, the hot water that reaches the coffee grounds will be lower than before, resulting in coffee that lacks the fullness and rich flavor it originally had!

Therefore, to avoid insufficient extraction due to lower temperatures, we can appropriately increase our usual water temperature setting by 1-2°C, or lower the height of our water stream during brewing to reduce contact area with cold air, ensuring that the hot water poured onto the coffee grounds has sufficient extraction power.

2. Preheat Coffee Equipment

In an article FrontStreet Coffee wrote two days ago titled "Should You Use Hot Water for Wetting Filter Paper?", the preheating of the filter cup was mentioned. In fact, not only the filter cup, but the container that holds the coffee liquid will also have different heat retention effects after preheating.

Take the server pot as an example. Without preheating, the temperature of the coffee liquid that falls into the pot after brewing is around 69°C, because the server pot at room temperature absorbs a certain amount of heat from the coffee liquid! After preheating, the temperature of the coffee liquid in the pot will be around 75°C, which will significantly extend the retention time of the coffee liquid's temperature and slow down the rate of heat loss.

3. Addressing Static Electricity Issues in Coffee Grounds

When temperatures are lower, friction and collision between objects more easily create static electricity, and coffee grounds are no exception! Finer grinds are more prone to generating static electricity. Static electricity creates two consequences: one is clumping, and the other is retention in the grinder - meaning 15g of coffee beans might yield less than 15g of grounds (because some coffee grounds get attracted to the coffee machine due to static electricity).

Although many grinders are equipped with anti-static devices at the exit, they don't have much effect! At this point, "distribution needles" and "air blowers" should come into play. Before extraction, use distribution needles (or other needle-like objects) to break up clumped coffee grounds, ensuring more comprehensive extraction and preventing significant deviations in the resulting coffee liquid's flavor. Meanwhile, an air blower can blow out the coffee grounds that have adhered to the grinder's exit, ensuring that your coffee beans yield the same weight of grounds every time.

In addition to the above details, for those using non-temperature-controlled kettles, it's best to pour more hot water than your target amount to reduce the cooling rate of the water inside the kettle. For those using temperature-controlled kettles, you can place the kettle back on the temperature-controlled base during the waiting intervals of blooming and water penetration to maintain temperature, thereby ensuring to the greatest extent possible that your coffee can be properly extracted.

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