How to Drink Pour-Over Black Coffee? The Best Tasting Temperature for Coffee & Can Cold Coffee Be Reheated

There's a good reason why people often say, "Coffee should be enjoyed while hot!" FrontStreet Coffee remembers a coffee enthusiast describing cooled coffee this way: "After one sip, my head hurt intensely. That bitter/astringent taste plus the woody flavor lingered in my mouth, making me withdraw for a long time."

Why does coffee taste so different when it cools down?

Temperature changes flavor expression and sensory perception. FrontStreet Coffee evaluates coffee beans at different temperatures—high, medium, and low—during cupping to determine their flavor profile, because coffee exhibits different flavor characteristics at various temperatures. This phenomenon occurs for two main reasons: coffee flavor compounds change with temperature, and human sensory perception also changes with temperature. Human senses can detect five basic tastes—sweet, sour, bitter, salty, and umami—with coffee most commonly expressing sweet, sour, and bitter flavors. These three taste compounds present differently at various temperature stages.

Bitterness and Bitter Sensation

In the world of taste buds, bitterness always ranks first in sensitivity! Whenever taste buds detect bitterness, they immediately send this signal to the brain: "Quick, tense up the nerves, bitterness is coming!"

Bitterness becomes more pronounced as temperature decreases because excessive heat creates a burning sensation in the mouth that overrides taste bud perception, reducing taste sensitivity. This is why when we taste dark-roasted coffee beans that already exhibit bitterness at high temperatures, they become even more difficult to drink when completely cooled.

Sweetness and Sweet Sensation

When food temperature approaches normal human body temperature, sweetness manifests most prominently. For example: add sugar to hot water and stir well, then taste at different temperatures—you'll find that when the sugar water is between 30-50°C, the sweetness is most apparent. The same applies to coffee liquid—when it reaches this temperature range in the mouth, sweetness and aftertaste are most pronounced.

Sourness and Sour Sensation

Sourness doesn't show significant differences as temperature changes. Similarly, if you put lemon juice in hot water, the sour expression won't vary noticeably across different temperature ranges. So why does the acidity of light-roasted coffee become exceptionally pronounced as it cools? First, light-roasted coffee naturally contains fewer bitter compounds than dark-roasted coffee, consisting mainly of sweet and sour flavor compounds. When temperature drops below 30°C, sweetness becomes less active, making sourness more prominent. Another factor relates to coffee oil oxidation.

Why does coffee develop unpleasant bitterness or sourness when it cools?

First, due to oil oxidation. Although pour-over coffee is filtered through paper that blocks most oils during brewing, some oil still dissolves into the coffee liquid and drips through the filter. As the coffee temperature decreases, this layer of coffee oil gradually re-congeals and floats on the surface, coming into contact with air. When this oil directly contacts air (oxygen), it begins to deteriorate and produces a strong, irritating rancid sourness (more apparent in light-roasted coffee). This easily oxidized oil is also the source of stale, oily flavors (more apparent in dark-roasted coffee).

Second, due to pigment oxidation and polymerization—simply put, coffee stains. During roasting, coffee beans develop brown pigments through caramelization reactions. Some substances produced by caramelization contribute caramel, chocolate, and other flavors to coffee, while other components oxidize and deteriorate over time, with flavors gradually becoming more bitter and burnt.

The Optimal Temperature for Coffee Tasting

As mentioned above, different coffee temperatures reveal different optimal expressions of taste and flavor. Freshly brewed coffee typically exceeds 70°C, making it quite challenging for the mouth to handle, so this is a good time to focus on aroma—volatile flavor compounds are most active at high temperatures. When coffee cools to around 60°C, it's the optimal time for experiencing rich, full-bodied flavors.

When coffee cools to 50°C, sweet and sour compounds become active, with floral, fruity, and nutty aromas being most prominent at this stage. At 37°C, sweetness expresses itself optimally. When coffee reaches room temperature, sourness is most intense. Different coffee beans have varying optimal tasting temperatures depending on their roast level—generally, beans with noticeable sweet and sour characteristics are best enjoyed around 30-50°C, while those with rich body are optimal around 40-60°C.

Can cold coffee be reheated?

FrontStreet Coffee does not recommend this practice. As temperature decreases, volatile flavor compounds also dissipate. Reheating at this point won't restore the coffee's original aroma. Furthermore, when coffee develops unpleasant flavors after cooling, reheating only intensifies these undesirable tastes.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473