In chemistry, combustion relies on three specific elements: Time, Temperature and Turbulence. What does this have to do with coffee?
Coincidentally, the three Ts of coffee are the same as the three Ts of combustion. However, the Ts of coffee are a lot less complicated and a lot more fun.
It is as simple as brewing at the right temperature, for the right amount of time and maintaining the turbulence that happens every time you brew coffee. Let's take a deeper look at the Ts to help you brew the perfect cup of coffee.
The extraction of coffee depends on the amount of time the water is in contact with the ground coffee. If there is not enough contact between coffee grounds and water, the resulting brew will be under extracted. Also, too much contact between coffee grounds and water leads to over extraction.
So, is there a correct brewing time? Approximately, the coffee brewing time should be 3 to 4 minutes. However, the time entirely depends on the brewing method and the grind size of the coffee. Below is a small list of brew time for common brewers:
- Pour Over Coffee: 3 to 4 minutes
- AeroPress: 2 minutes
- French Press: 4 minutes
- Moka Pot: 3 to 4 minutes
- Espresso Machine: 25 to 30 seconds
Brewing temperature affects the rate of extraction. The hotter the water, the quicker the coffee extraction will be.
The higher the temperature, the more difficult it becomes to control the rate of extraction. This can lead to bitter and over-extracted coffee. So, it is important to use optimal-temperature water. On the other hand, the coffee will be watery and under-extracted if the temperature is low.
The ideal temperature for extraction lies between 88°C to 96°C.
We may have to raise or lower the temperature based on the roast type. For instance, we can slightly increase the brew temperature of coffee for a lighter roast to achieve a full-bodied cup. Here are some equipment you can use to control the temperature:
If you do not want to invest in a kettle or a thermometer yet, you can turn off your stove the moment bubbling starts. This will make sure the water is hot enough for brewing and not too hot to burn the coffee.
Turbulence in coffee brewing happens when the water passes through and over the coffee grounds. During this time, the water flows through the coffee particles and enables extraction. Although it is not as important as brew time or temperature, turbulence does play a significant role in how the resulting cup tastes.
In brewing methods like Pour Over, water poured too slowly over the grounds can create channels in the ground that are unevenly wet. This can lead to improper extraction.
That's why, we need to bloom the coffee grounds before brewing. It allows the gas to escape and the water can fully absorb the flavour in the coffee.
In case of full immersion brewing like French Press, we need to push the water properly to extract coffee thoroughly. By stirring the grounds after 30 seconds of pouring, we can control the turbulence and ensure the coffee is fully immersed in water.
Unlike the other Ts, turbulence can not be decoded with quantifiable numbers. We can, however, improve it with some trial and error.
A good cup of specialty coffee is a result of the three Ts working together. While we can play around with one variable to change the resulting cup, paying attention to all of them only helps us make better coffee.
Further, we need to keep in mind that each variable is separate and we need to manipulate them independently.