Understanding and Thoughts of Coffee Science

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(Peter Tam, Kaffa Café)

After years of learning and understanding about coffee, we had formed our own understanding, or even we call it coffee theory. Although we cannot be sure if it can be called a full established theory or not, we do have our own understanding about coffee, espresso, and many things related.

Recently, we heard about a speech about coffee, specially about espresso, who is famous in the science of coffee and world coffee industry. We do not mean to offend neither to be rude to the expert, but we would let people know what we think about coffee and its science, in our mind.

There are several points , which I would discuss here, with you, all the readers of this article. If anything wrong, you can let us have your comments and opinions, which are mostly appreciated.

Let’s start.

Question 1) Is it possible to know coffee well in terms of analytical chemistry?

It is mainly described in a book about espresso and its chemical analysis for its tastes and brewing results. Although one can find out some of the components in espresso drinks, it is almost impossible to understood beans, as it is a kind of organic material and so complex as any other organic materials. As general understanding, I suppose, no organic materials can be well understood in terms of analytical chemistry in details of its components and deep into its molecule structure.

I had no experience of other industries, but know something about the Chinese traditional medicines, they are mainly herbs, minerals, entrails, and so on, all are organic materials. The complex of Chinese medicines is more complex due to the organic structure of the human’s body and their organs. As one may know that, the traditional way of preparing Chinese medicines is boiling in a crock or similar. It tastes bitter, some of them are very bitter. I is the reason why very young people never like it, and Chinese people used to say that, good medicine tastes bitter and good advice is harsh to the ear.

Suppose we had found some tastes is composed of mainly something at ratio of 50% or more, can we be sure of its key influence or not? It is well known in organic chemical industry that the influence of a “catalyzer” is very important and even the key of the right results of a chemical reaction.

As in modern Chinese medical industry, people try to concentrate the Chinese traditional medicines and get 70%, 80%, or more of the components, and drop the most part of the water and very few (in ratios) of others, the results are usually in much loose of the effects, if not all. In fact, they loose all effects for most of those examples. It can be a reference for us, as we are trying to understand of coffee, another organic material.

Question 2) The deeper the roast, the more the beans loose its tastes!

“The deeper the roast, the more the beans loose its tastes!”, yes, it sounds quite right and even great. But, we can also think of it in another way. Try to smell the green beans, and you can be sure that it does not have any smell like coffee. The smell of coffee only comes after the beans are roasted to certain level, so as its tastes. Considering the complex of smells and tastes of coffee, we can suppose that their smells and tastes comes out more or less at different level of roast. If they are much more “over” roasted, some of the smells and tastes can be killed.

But, what is the standards? We can only find it by experiments, I suppose. Based on our general understanding about coffee and Coffee Science, we can never get it in terms of analytical chemistry protocols. We can generally speaking about over- and under- roasted, reference to the “standards”, but we do not really know the “standards”, the reference point.

Question 3) Water temperature for brewing coffee

As he said, to brewing drip coffee, one use boiling water, but for espresso, they use only water heated to 88℃ or 90℃. It is simply not true, so we can be sure as any body else.

People well know that, one can never use boiling water to brew coffee. Otherwise, the coffee grounds will be burnt. For any brewing tools around the world, whether drip coffee or even Arabic coffee, they are designed not to make the water boiled.

As one of the very simple example, one can use the hot water from the espresso machines to brew the coffee in a French press. Does it leave more flavors or not? Surely not. The difference between drip coffee and espresso is the water pressure, not the water temperature, or to say the combined results of water temperature and water pressure.

Question 4) Does it work to lengthen the lasting time of after-taste by pressurizing the beans, and why?

I would like to know any research work and the paper to discuss about such a result.

It is Kaffa Café

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Comment by Peter Tam on March 30, 2008 at 8:07pm
Thank you for your info. I shall try to find that book.
Comment by Bel Townsend on March 30, 2008 at 12:37pm
Once again, thanks for a very interesting and useful post! In response to Q.1), I found a reference in my own work, it had a very comprehensive section on the chemical make up of coffee (presented in a way even I could understand!). It was quite surprising - how when making espresso, you are actually using less than 3% of the mass of the bean, etc. If you are interested, the book is:
Debry, G., 1994 'Coffee and Health' John Libbey and Co. London

thanks again

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