Ideal water temperature when making coffee 0
Guide Coffee

The Perfect Water Temperature For Coffee Brewing

At different times in the past and many cultures, coffee was almost boiled with water to form a thick, dark, and bitter drink. With the journey to conquer the world of coffee, we have found better ways to brew. With useful scientific knowledge, a traditional belief has been established that coffee must be brewed in hot water. And never in the history of coffee has taste been better than these decades; However, in the third wave, art in the opposite direction of science recognized cold-brewed coffee (cold brew) as a way to drink coffee without temperature.

Why must brew coffee with hot water?

Today, the popularity of Cold brew has made every basic concept of making coffee in hot water suspicious. Temperature, perhaps the most common form of energy used in making coffee. And there are two reasons for this; 
  • First, the hotter an object, the more energy it has. Therefore, the hotter it is, the more the molecules (or atoms of matter) vibrate (i.e., the higher the kinetic energy); 
  • Secondly, temperature follows the rule of energy conversion, going from high energy molecules to less energy molecules.
Ideal water temperature when making coffee 0
This applies to brewing coffee in two ways. Firstly, the higher the temperature, the higher the kinetic energy of the water molecules. Therefore, they have higher mobility, which increases their ability to remove compounds from coffee beans due to more potent physical force – Put, the temperature helps to dissolve coffee in water better. (more specific below). Secondly, heat from the water will be lost during the extraction process due to heat conduction through coffee, mixing equipment, the environment… so hot water provides a compensation so that the coffee remains hot enough after mix – this is important, right here. Because the right water temperature will help you feel the flavors from coffee better, if the temperature is low, coffee may taste thin (low viscosity), flat, and have a moderate flavor intensity. As the temperature increases, the soluble molecules in the extract increase their activity, helping us to feel the taste clearer, more productive, and more delicate. Usually, cooled coffee will be more bitter and sour. However, it is not really that the sharp or acidic substances increase, but because the familiar flavors have been reduced, the smell and taste are more pronounced than the other characters.  

The best temperature for making coffee

Finally, how much is the water temperature enough to balance all the flavors in the coffee in a balanced and delicious way? Although that decision is personal, more than half a century of research has determined that most people prefer coffee where it is brewed with hot water between 90 and 96°C. Although the proposed temperature of 90 – 96°C can be found in numerous articles & scientific papers, however, the first time it was published was in 1950, by Dr. Earl E. Lockhart (SCA). Since then, this temperature frame has been present in the SCAs coffee-making manual to date.
Ideal water temperature when making coffee 1
This desired temperature range is slightly below the boiling point of water (100°C at standard pressure). If the temperature is too low, some of the main compounds will not be efficiently extracted, and people will not obtain all the desired flavors, high temperatures will favor the extraction of difficult-to-dissolve compounds. Described in the chart below, bitter, astringent, phenol compounds dissolve in a very high-temperature range and affect the overall flavor balance of coffee. Professional baristas use a thermometer (or a built-in thermometer) to keep the water temperature stable. Although you can easily order one, if you feel it is not necessary for homemade concoctions. You only need to take out the boiling water and wait for about 30 seconds to a minute before pouring.  

Master the taste by the temperature

As mentioned from the beginning, the effectiveness of the extraction process depends on the solubility of the extracted molecules. Accordingly, the solubility of most compounds in coffee often increases with temperature. However, this relationship is not always “linear” in all cases. As shown in the following figure, while citric acid has a linear increase in solubility with temperature, the solubility of caffeine increases by four times between 80 and 100 ° C. In other words, within that narrow range, small temperature changes have a significant effect on the solubility of this compound. Therefore, the solubility ratio between citric acid and caffeine varies with the water temperature.
Ideal water temperature when making coffee 2
This also explains why coffee extracted at low water temperatures (for example, cold brew) often lacks strength due to less total dissolved solids as well as the lack of solubility of compounds. Strong impact on taste. However, this can be partially offset by a much longer extraction time (more specifically below). Another effect of more water temperature in the natural gas is, the higher the temperature, the lower the viscosity of the water. The lower viscosity means that water can easily penetrate the coffee bean structure and crept into spaces (even within the fibrous cell structure) to dissolve the compounds present in coffee. This effect explains why the amount of oil (lipids) in coffee increases with increasing water temperature.  

Evaporation compounds & water temperature

For volatile compounds, things are a bit more complicated, and it involves some other physical laws. Put the solubility of a gas depends on the water temperature but in contrast to solids. Following Henrys proposal, the increase in temperature causes gas molecules to enter the gas phase (evaporation). Therefore, the aroma compounds in coffee will be released into the air during the extraction process. The higher the temperature, the more scent loses. Of course, the spreading of coffee aroma during the extraction (and immediately afterward) contributes to the overall taste and taste-experience, but reduces their concentration in the cup.
Ideal water temperature when making coffee 3
Cold-brew & nitro brew; What about icy concoctions, nitro coffee, they are considered part of the specialty coffee movement? And there is almost no concern about the water temperature during the extraction process. More specifically, if coffee is brewed with cold water, they certainly lack the temperature to extract some of the low polar compounds (like coffee oil). The higher polar compounds do not “stand” in low temperatures and are still relatively well extracted. However, a longer extraction time (8 to 24 hours) is required to allow a sufficient amount of flavor. On the other hand, the loss of volatiles during extraction is much less than that of hot extract, which makes these aromatic molecules “trapped” inside beverages. Therefore, cold coffee provides a drink that is surprisingly different from traditional hot brewed coffee, provided that the time required to extract is longer. The long incubation time in cold brewing can cause oxidation of the coffee, so it must be strictly controlled for the ability to contact air during the extraction process. In the end, the article was quite short, but long enough with a content that didnt revolve around the heart of the coffee bean. Because there is always the fact that the more you try to understand the coffee bean, the more it reveals its complexity, so understanding the most basic brewing will help us make a more informed decision to have a suitable coffee cup.

Leave a Reply

Your email address will not be published. Required fields are marked *