The Heat is On: Elevate Your Coffee Game with the Right Water Temperature

You might think coffee beans and the way they are prepared are the determining factors to whether you ‘screw your brew’. While not wrong, you may be overlooking the main ingredient in your beverage: water! It makes up 90-98% of your coffee, depending on your pour.

The optimal brewing temperature range for coffee is between 90°C and 96°C (195°F and 205°F), which would extract the perfect amount of flavour and aroma compounds.

Quality of Water

Depending on where you live, your tap water will have different chemical and mineral compositions, affected by both the source of the water and the treatment process. To take as much guesswork as possible out of the game, use fresh, filtered water for your brew. It also helps to prevent any unwanted tastes in your espresso.

Under-Extraction vs Over-Extraction

As a solvent, the higher the water temperature, the more coffee gets dissolved. Subject to how you like your brew, take time to consider the effects of under-extraction and over-extraction. In general, brewing coffee at a lower temperature (under-extraction) will result in more sour, acidic flavours. On the other hand, higher temperatures (over-extraction) create more bitter, astringent tastes.

For a better understanding of acidity, more information can be found here.

Water hardness can also affect the extraction process. Hard water is higher in mineral content, more specifically in calcium and magnesium, whilst soft water has low mineral content (note: it is possible for filtered water to still be considered “hard”). 

If the water is too soft, it will lead to coffee compounds being less soluble, resulting in under-extraction. Optimum water hardness should be around 75ppm to 250ppm. In the context of Singapore, our tap water is relatively soft, at an average of 64ppm. Using a water filtration system can help you monitor these levels.

The Precision of Temperature 

The trick to measuring water temperature precisely to ensure it falls within the recommended range, is to use a coffee thermometer.

Coffee thermometers have long probes, often paired with a clip to attach to your container. They are available in two main types – digital and analog. Digital thermometers are known for their precision, while analog models excel in durability. Some even come built into kettles. Take your pick!

Analog and digital coffee thermometers, as well as kettles equipped with built-in thermometers, are some of the many tools available for achieving precise water temperature readings.

What Is the Roast Level of Your Coffee?

If you want to get down to the nitty gritty details, different roast types can require different levels of temperature. Lighter roasts are generally brewed at a marginally higher temperature than darker roasts, as they require more energy to extract. 

Let’s take our house blends as an example. As they are in the range of medium to medium dark roasts, you should aim for a temperature of around 90°C to 93°C.

How Long Should You Brew Your Coffee?

As a general rule amongst the coffee community, here are the recommended brewing times for each method. These are good starting points to work off from, adjusting the temperature and brew time to your desired strength. If you can manage consistent and/or precise brewing temperatures, then you might want to log your temperature and brew times, until you get a brew that is perfect for your coffee…and more importantly, perfect for your taste.

What About Cold Brew?

While coffee has traditionally been brewed with hot water over a short duration, cold brewing trades temperature for time. Not to be confused with iced coffee, ground coffee can be steeped in room temperature or even cold water (and left overnight in the refrigerator) over an extended time. Depending on the brewing temperature and the desired strength, one commonly takes about 12 to 20 hours to produce a cold brew.

You would usually find that the resulting coffee is smoother and has lower acidity, as not all flavour compounds will dissolve at lower temperatures and in that duration. The flip side is that for the same reason, a cold brew coffee may have less character, with a more mellow profile.

Pairing the perfect water temperature with the ideal coffee blend is an art. At Six Four Coffee, we master both. Indulge in our premium beans and cutting-edge machines to elevate your coffee experience!