Why Does Water Taste Sweet After Drinking Coffee? What's the Connection with Coffee Water, Olfaction, and Retronasal Smell?

Whenever guests come to our café and sit down to enjoy a cup of coffee, FrontStreet Coffee always serves a glass of plain water first, allowing them to hydrate while waiting for their coffee. Interestingly, some customers have finished their coffee and asked FrontStreet Coffee: "Why does your water taste sweet?"

In fact, FrontStreet Coffee only provides regular plain water to our customers. So why does water taste sweet after drinking coffee? Today, FrontStreet Coffee would like to share the secret behind this phenomenon with you.

The Science Behind Coffee's Aftertaste

Compared to other beverages, coffee's flavor lingers in the mouth for a longer time. Take traditional espresso as an example: when we taste espresso, the first sensation is the intense bitter and aromatic flavor. Only after careful savoring do we perceive complex notes such as nuts, caramel, and chocolate. As we swallow the coffee, the residue remaining in our mouths creates a slightly sweet sensation. If we don't "rinse" with water, this subtle sweetness can last for up to 15 minutes.

This happens because small molecular substances that provide fruity and acidic flavors dissolve with the help of saliva and dissipate with the act of swallowing. However, other components like lipids, natural fats, and oils—what we commonly call "oils"—tend to remain more on our taste buds, giving us a slightly rough, astringent mouthfeel. But in a good cup of coffee, this astringency doesn't create too many negative sensations; rather, it provides a pleasurable experience.

The Phenomenon of "Hui Gan"

We generally call this phenomenon "Hui Gan" (回甘), which is a term used to describe coffee's aftertaste. It's not actually the same kind of sweetness as eating sugar, but rather a sensation that emerges after the bitterness and astringency fade away. Therefore, when we drink water immediately after consuming coffee to "rinse" our mouths, the residual oils that create these bitter and astringent sensations are washed away, reducing the burden on our taste buds and creating the perception of "sweetness."

Enhanced Sweetness Sensitivity

Besides "Hui Gan," black coffees like pour-over or espresso are high-concentration liquids relative to water. After drinking coffee, our taste buds have been "bombarded" by acidic (or bitter) flavors, and their sensitivity to sweetness dramatically increases in the short term. This is similar to how water tastes exceptionally sweet after eating a lemon or drinking traditional Chinese medicine.

Conclusion

Overall, whether it's due to "Hui Gan" or the changing sensitivity of our taste buds to sweetness, this phenomenon represents one aspect of coffee's comprehensive sweetness profile. Next time you finish your cup of coffee, try drinking some plain water and see if, as FrontStreet Coffee mentioned, the water indeed tastes sweet.

- END -

FrontStreet Coffee
10 No.1 Bao'an Front Street, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473