The effect of temperature on Coffee how to feel the Coffee Flavor during High temperature and cooling

Have you ever had the experience of getting a cup of hot coffee, only to find that the flavor and aroma are different when it is cooled?

When this happens, you may start to drink delicate flavors and aromas that you couldn't taste before. You may find that your coffee now has a distinct sweet, fruity or floral flavor.

This change in flavor is due to specific chemical reactions triggered by temperature fluctuations. To understand why and how these things happen, you need to understand the science behind them.

How do we feel the flavor and aroma?

Coffee is a very complex beverage. Noodles have more than a thousand aroma substances that form what we smell and taste through coffee brewing and tasting. Forty of these 1000 substances are obvious aromas that are more commonly found in coffee.

These aroma substances are produced from the coffee roasting process, when the coffee beans are heated to produce sugars, carbohydrates and nitrogen compounds. The sugars in raw coffee beans are degraded by heating during baking, where they become caramel (producing a familiar caramel smell) or brown through Maynard reaction.

This process produces volatile compounds that are converted into gases that evaporate at room temperature. In the process of volatilization, we strongly feel these aromas, and through our tongues and noses, we feel these flavors and aromas, which are various aromatic compounds related to sweetness, ranging from chocolate to fruit.

The taste buds in our tongues have sour, bitter, and sweet taste receptors that respond to certain chemicals and then transmit taste perception to our brains. Chemicals in volatile compounds spread from our mouths to the nose to stimulate the posterior nasal olfactory system. The collection of nose-waiting olfactory organs is also important for us to perceive flavor and aroma.

When we feel other flavors, it may be the result of the interaction of many organic acids, sugars, oils and other substances. Chlorogenic acid in raw beans will produce bitter taste, while quinic acid will produce bitter and astringent taste.

If the coffee we drink has a sour taste, it can increase our understanding of the sour taste, which we associate with volatile compounds when we drink it, such as the acidity we drink with the aroma of lemon. Once there is a way to connect them, the sensory ability will be enhanced.

How does temperature affect coffee extraction?

We all know that extraction will greatly affect the flavor and aroma we feel in coffee, and the water temperature used to make coffee will also have a great impact on the extraction rate of coffee.

The molecules in the coffee are extracted at different stages according to the water temperature, and hot water can extract most of the compounds we feel in the coffee. The higher the water temperature, the easier the compounds in the coffee are extracted.

The more this molecule interacts, the more the amount of extraction. When this happens, water molecules dissolve more compounds from coffee molecules, affecting the sense of taste and smell we feel in coffee.

If we use low-temperature water extraction, we will not be able to extract the full flavor of coffee, which contains these fascinating volatile compounds.

However, the study points out that this can change when coffee is brewed at a low temperature, such as extracting coffee at a low temperature (ranging from room temperature to zero) for several hours.

This will lead to complex flavor characteristics because this extraction method will be changed to the extraction equilibrium of most compounds. It contains sugars, organic acids, chlorogenic acid, caffeine and other insoluble compounds that require more extraction time.

Long-term and low-temperature extraction will allow sugar to be fully extracted, making cold-extracted coffee sweet and caramel-like, while coffee will be less bitter and astringent.

Higher water temperature will extract flavor and aroma.

Coffee is usually brewed at a temperature of 82 °C to 85 °C. However, this temperature can be too high to cause burns, and the temperature in this range may not be able to drink the flavor and aroma of coffee. The best way to drink coffee in this way is to sip or sip, only need to inhale a small amount of coffee liquid, and inhale air to quickly cool the liquid.

When it is about 70 degrees, the flavor and aroma of coffee begin to be clearly perceived. At this temperature, coffee releases a lot of heat, which can enhance the experienced aroma, but inhibit the taste sensation of the tongue and affect the flavor sensation. Volatile compounds are released faster and evaporate faster at this stage.

The strong aroma can also be felt at a temperature of about 70 °C and can last up to about 60 °C. It is usually difficult to feel the flavor at this stage, especially when the coffee is very delicate. In fact, some studies have pointed out that different coffees brewed with the same roasting degree may taste very similar at higher temperatures.

The main things we can feel at 70 °C are bitterness and aroma, and the flavor part can only feel the smell of baking.

These flavors will last until the coffee cools again at 10 °C. at this temperature, we may find that the bitterness increases, and some people say that the bitterness of the coffee is the strongest around 56 ℃.

Flavor and aroma during cooling

When the temperature is below 50 °C, you will feel a significant change in the flavor and aroma of the coffee, and the aroma becomes less obvious, mainly due to the reduction of steam produced when the coffee is cooled.

The bitterness is reduced, so that the human body can feel more complex flavor. Between 31 °C and 50 °C, the most flavor can be felt, mainly related to acidity and sweetness. The highest sweetness is about 44 °C, while the bitterness is the least obvious at about 42 °C.

Interesting small changes may occur between 31 and 37 °C, where the volatile compounds related to sweetness, fruit, flowers, herbs, acidity and nutty flavors are more obvious, when we can really experience the flavor characteristics of a cup of coffee.

Compared with 44 °C or 70 °C, acidity feels best at lower temperatures (for example, 25 °C). For example, drinking a cup of Kenyan coffee at this temperature will make its flavor more lively and sour brighter. It enables us to taste the full flavor of this single coffee and shows us that the same coffee may produce different tastes at different temperatures, while the same cup of coffee tastes worse at higher temperatures.

Whether you like hot coffee or cold coffee, it is important to understand the effect of temperature on the flavor and aroma you feel.

The next time you make your own coffee, record the flavor and aroma you feel at different temperatures and try to find out the "ideal range" between sour, sweet, bitter and aroma.

This will help you find out which type of coffee you prefer (coffee with more acidity or sweetness), or which flavor characteristics of the coffee you prefer.

No matter which way you choose, you can better taste the flavor of the coffee at any temperature.