Coffee and soy milk are often compared with each other, but the two are actually completely different from plant source to production method. This article starts with botanical classification, sorts out the fundamental differences between the coffee tree and soybeans, then compares the water-ground and filtered process of soy milk with the process coffee must go through—roasting, grinding, and brewing—and further explains the sources of the four tastes in coffee: acidity, bitterness, sweetness, and body, as well as the significance of the oils on the coffee surface to espresso. The article also introduces the four common stages of coffee roasting, helping beginners build a systematic framework for understanding coffee. It is suitable for enthusiasts who are just getting into coffee and as an introductory reference for baristas.
A netizen suddenly asked, "What is the difference between coffee and soy milk?" Hearing this question, I was a bit stunned for a moment. How could coffee and soy milk be compared together? Still, after recovering, I should seriously talk about the differences between the two.
Let's start from the botanical perspective. The sources of coffee and soy milk belong to two completely different worlds. Soybean (that is, yellow bean) is classified under Magnoliopsida, Fabales, Fabaceae, and Glycine. The coffee tree, however, is an evergreen tree in the Rubiaceae family. Strictly speaking, coffee beans cannot really be considered true beans; they merely look like beans in shape. The two are not in the same classification system at all.
Looking at the production methods, soy milk is made by soaking soybeans until they swell, then grinding, filtering, and boiling. So the word "milk" is used very accurately, because during grinding the beans do indeed directly release liquid, and that is soy milk.
The production path of coffee is completely different. First, it must be roasted, and this alone creates a huge gap from soy milk. More critically, coffee is made by grinding roasted coffee beans and then brewing or boiling them; water is added later. Soy milk is not like this. When it is ground, water is already released, after all, because it has gone through the step of soaking and swelling beforehand.
Taken together, coffee is not a type of soy milk, and the reason is far more than simply "both are made by boiling beans."
From the perspective of production technique, the two also cannot be equated. Roasting is an indispensable part of coffee, and the roasting process is usually divided into four stages: Cinnamon Roast (also called City Roast), Vienna Roast, Italian Roast, and French Roast. The specific divisions can be seen in the figure below.
Without roasting, there is no coffee.
Finally, distinguish them by taste. The final taste of coffee mainly depends on the water-soluble substances in the coffee beans and the oils produced on the surface of the beans after roasting. This point is quite crucial, because this layer of coffee oil is precisely the source of the flavor of Italian coffee, that is, the espresso everyone is familiar with. The taste of coffee is actually a combination of four sensations—"acidity, bitterness, sweetness, and body."
Looking back at soy milk, the flavor of the soy milk we are familiar with mainly comes from soybean protein. Bitterness and sweetness are closely related to the production method and cannot completely be regarded as inherent properties of the ingredient itself. The most important point is that soy milk should not be sour. Once it turns sour, it means it has spoiled.
The above content is compiled by CoffeeHunters, a coffee news website.
