The Secret of Coffee extraction factors affecting Coffee extraction

Is there any secret to making a good cup of coffee?

Now let's make a summary of the experience of coffee extraction.

Tip 1: water temperature

Let's put aside the argument about water temperature and take a look at the two most extreme methods of making coffee today.

Water temperature can directly affect the integrity and speed of coffee extraction. So in principle, you can make coffee in ice water, but it takes longer. The lower the water temperature, the longer the extraction time you need. As long as you have enough patience, the quality of the coffee you make will be guaranteed.

Ice drop coffee is based on this principle to make coffee. The coffee powder is mixed with cold water and soaked in the refrigerator for a night to a whole day. If the extraction integrity of caffeine is not greatly affected by the water temperature, then the extraction degree of organic components in coffee depends entirely on the water temperature at the time of production. As a result, the caffeine content of coffee brewed in cold water does not change much, but the bitterness is much lighter than when brewed in hot water.

After looking at the example of making coffee at very low temperatures, let's take a look at the result of boiling coffee. High temperature can make the extraction speed of coffee faster, and the extraction degree of organic components in coffee is more complete. But coffee grease is a special case. Although the main ingredient is a foam formed by some organic components in coffee, if the water temperature is too high, the oil will evaporate with the steam. As a result, coffee made from boiling water is very thin, but bitter and high in caffeine.

Trick 2: grinding

The degree of grinding of coffee can directly affect the extraction time of coffee. The finer the coffee powder, the larger the contact surface between the particle and water; conversely, the thicker the powder, the smaller the contact area between the particle and water.

Again, let's look at two extreme cases. If we grind coffee powder as fine as talcum powder, the contact area between coffee particles and water will be infinitely expanded. So we only need a very short extraction time to get a delicious cup of coffee. For example, the coffee powder used in Turkish coffee is so delicate that people boil water and coffee powder together and drink it. The coffee made by this method is very strong and bitter, and because the coffee powder is too fine to be filtered, there will always be some fine residue at the bottom of the coffee. But if the coffee powder is too meticulous, you will not be able to make coffee because the coffee powder will block the filter and the water will not flow out at all.

Now let's see what happens if we use whole beans to make coffee. Of course, if the time is long enough, we can indeed extract unground coffee beans. But this is very wasteful because it is impossible for hot water to soak the whole coffee bean completely, resulting in most of the substance being thrown away without extraction.

From the above two methods, we can conclude that the most perfect degree of grinding should be between the two, and of course we can decide when to brew coffee in hot water according to the content of caffeine, coffee oil and organic matter. If you use high-quality coffee beans, but the coffee is not good enough, it means that the coffee powder is too coarse; if the coffee is too bitter, then it is possible that the coffee powder is too carefully ground.

Trick 3: extraction time

For the time being, let's not consider other factors such as water temperature, grinding degree and water / powder ratio, but only consider the time of coffee extraction. If you want coffee to have a lot of caffeine and thick coffee oil, while controlling the content of bitter substances, then the extraction time you need must be very accurate.