Coffee Fun Facts | Why does coffee smell better than it tastes?

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Every time I grind the coffee beans into powder, it smells so good. The aroma spreads as soon as the hot water goes in. It is such a pleasure to smell the aroma of coffee while brewing it! After brewing it, I can't wait to take a sip. Wait... is the coffee I drink fake? Where did the floral and fruity aromas that were emitted when brewing just now go! !

In fact, this is related to our sense of smell and taste! In a broad sense, taste includes the signals transmitted to the cerebral cortex by the five senses (vision, hearing, smell, taste, and touch), and then processed by the central nervous system. Therefore, our five senses are the medium of taste signals; but in a narrow sense, we usually think that taste refers to "the taste of food fed back by the joint action of the nasal cavity and taste buds". The reason why we can feel so many flavors in coffee is because of the existence of aroma substances. These aroma substances have one thing in common - they are volatile .

The aromas we smell belong to the aromatic substances of coffee, most of which are volatile, so we can sense them with our sense of smell; another part is volatile and water-soluble, so we can sense it with our sense of smell and taste; a small part is water-soluble and can only be sensed by our sense of taste.

Some sweet and sour flavor molecules are volatile and water-soluble, so they can be enjoyed by both the sense of smell and the sense of taste; but the unpleasant bitter and salty taste is water-soluble and non-volatile, so it can only be felt by the sense of taste.

Why is it so difficult for us to sense those non-volatile components?

| Baking

When roasting green beans, if the roasting speed is too fast, the Menard reaction will be too slow, resulting in many non-volatile components not being decomposed, and no matter how sensitive the tongue is, it will not be able to taste them. But this does not mean that the more Menard reaction, the better, because too much non-volatile components will make the taste too irritating, or even make people feel smelly, so the coffee roasting time must be just right.

| Coffee beans freshness and storage

Why do we emphasize that coffee beans must be fresh? It takes about 15-20 days for coffee beans to reach their peak flavor after being roasted. Coffee will release gas, and even if it is sealed, the flavor of the coffee will slowly dissipate. When all the flavors are gone, only the most basic woody flavors are left, and naturally no non-volatile substances can be felt!

Even if you have good coffee beans, if you don’t store them properly, the flavor of the coffee will be greatly reduced! Generally speaking, when storing coffee beans, we should pay attention to the oxygen gas partial pressure, air moisture content and storage temperature. Any of these factors will cause the non-volatile components of the coffee beans to gradually disappear, and even cause some oils to oxidize, producing unpleasant odors.

Coffee is blessed with a large and complex variety of chemical substances. In addition to the compounds mentioned above, there are other organic acids, inorganic acids, alkaloids and other ingredients.

When grinding or brewing, these volatile components or organic acids vaporize, giving us the pleasant coffee aroma.

How do you feel these volatile components?

Our sense of smell is actually divided into two types: prenasal olfaction and retronasal olfaction .

The breadth and accuracy of olfactory recognition exceed that of taste and mouthfeel, because smell is the only sense organ with bidirectional function. The nose can smell the odor of the external world, which is called "orthonasal olfactory", but the oral cavity can also "smell" the odor of food eaten into the mouth, which is called "retronasal olfactory".

Simply put, this is because we have two senses of smell: one is the "prenasal olfaction" produced when you inhale from the external environment, and the other is the "retronasal olfaction" produced when the smell passes through your nasal cavity and exhales.

Coffee has volatile caramel aroma, cream aroma, sour aroma, floral aroma, fruity aroma, herbal aroma, nutty aroma, grain aroma, resin aroma, wine aroma, spice aroma, burnt aroma, earthy aroma, wood aroma, medicine aroma, etc., all of which are presented by the front nose and back nose senses.

However, the two have different degrees of aroma recognition and the degree of excitement they cause. Before appreciating the aroma of coffee, you must first understand the difference between the sense of smell in front of the nose and behind the nose in order to achieve twice the result with half the effort.

How to appreciate the flavor of coffee?

1. Volatile aroma

When coffee is ground, the lighter floral and fruity aromas are highly volatile and are released first, and can be smelled from a distance.

Next comes the medium molecular weight caramel, nuts, chocolate, and almond flavors, but the drift distance is shorter than the former, so you need to get a little closer;

Finally, there are the high molecular weight pine resin, thiol and caramel aromas. Since the molecules are the heaviest and the aroma is the shortest, these aromas are mostly found in medium to dark roasted coffee, and you need to put your face close to the top of the coffee powder.

Therefore, when appreciating coffee, when smelling the dry aroma, you need to change the distance between your nose and the coffee powder so that you can smell the diverse aromas of low, medium and high molecular weight.

Some volatile aromatics cannot vaporize at room temperature and need to be brewed with high-temperature hot water to release their aroma. This is the moist aroma of coffee.

2. Water-soluble flavor

The aroma has vaporized and evaporated during grinding and brewing, and has not been integrated into the coffee liquid. Therefore, when you drink the coffee, your taste buds in your mouth can only tell you that the coffee is sour or bitter. This is the effect of the sour, sweet, bitter, salty and fresh water-soluble flavor molecules in the coffee.

In principle, all areas of the human tongue can sense these five tastes, but the tip of the tongue is sensitive to sweetness, the sides of the tongue are sensitive to sour and salty, the root of the tongue is more sensitive to bitterness, and umami can be tasted by the entire tongue.

3. Taste

The taste is the result of the mutual restraint and competition of the five flavors of sour, sweet, bitter, salty and fresh. If one flavor is too prominent, it will suppress or enhance the performance of other flavors, and even affect the taste.

For example, if the salty component is too high and meets acidic substances, the astringency will be magnified; if the slightly salty taste meets sweetness, the saltiness will be suppressed and become mild and smooth, and the saltiness will sometimes offset the bitterness. The sourness and sweetness will bring out a delicate fruit flavor, which is the taste that most people like.

There are many flavors in coffee, and tasting coffee is not just about drinking it. Drinking coffee is the result of the combined operation of vision, smell, and taste. The sensitivity of the senses is either innate or the result of hard training. However, everyone's perception of flavor is different, but no matter what, it is just to make yourself enjoy a cup of coffee better!

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