What is coffee chromatography and how does it work: Chromatography is the name of a series of techniques aimed at separating and measuring the proportion of the different constituent elements of a substance. That is, disintegrate what in chemistry is called a complex mixture, a combination of many components of variable proportions.
Each component has a characteristic color and movement in the different methodologies that can be applied and its combination generates an image or graph with colors that represent the different elements of the mixture when separated. In the case of coffee, it is a versatile tool that extends the possibilities of analysis and tracking of elements from the soil of the farm to the cup that the final consumer tastes.
To learn more about this process and how to implement it, I spoke with Hernán Cabra, CEO of Laurino Coffee in Colombia and Q processing manager , and with Julián Cucuñame, founder and scientific director of the biotechnology and bioengineering company CuBa BIOTEC . Read on and find out what they told me.
Coffee chromatography and how it’s applied in the industry
There are two basic types of chromatography , depending on where the chromatogram is performed. On the one hand, there is planar chromatography, either on paper or thin layer. On the other hand is column chromatography that includes gas, liquid and supercritical fluid chromatography.
In any case, there will be a base substance called the stationary phase, in which the elements will move when separated, and a substance called the mobile phase, in which the complex mixture to be analyzed will be dissolved. The substances used as phases and the states of matter are determined by the specific chromatographic technique.
In coffee, chromatography was revealed as a fundamental tool for the entire industry . “Before, people didn’t really know what was happening in the grains, what results were being obtained and why,” explains Hernán Cabra“.
“Chromatography helps to identify this type of results and to analyze how it can be replicated. Also, the other type of chromatography used for soils, which is a simple technique, helps identify the amount of minerals, the composition of the soil, and nutritional deficiencies. Chromatography is an instrument that allows me to know what I have and what I don’t, it helps to make decisions, both in nutrition and fermentation , and always obtain the same thing.” he points out.
For his part, Julián Cucuñame says: “The etymology, kroma and graphos , which are the two Greek words from which it is derived, refer to the basic characteristics of a color and the study of that color on a surface or in a structure”.
“When we use paper surface chromatography, what happens is that the substance to be analyzed is subjected to an extracting agent, generally a basic solution, which when reacting with the sample, usually acidic, reveals patterns of colors and shapes that indicate a result and we must interpret it according to previously developed patterns.”
Gas chromatography or paper chromatography
Gas chromatography is an expensive and specialized methodology that offers very precise information. Hernán explains: “paper chromatography is what is done in the field with a paper filter, where I do a certain protocol to extract the soil and be able to identify the minerals it contains, that is more artisanal.”
For its part, “gas chromatography has more to do with a laboratory topic, a little more scientific, it requires certain equipment and instruments that are expensive, not available in many places or not many laboratories have them” he points out.
On the other hand, paper chromatography is available to anyone . “This chromatography on a paper surface is very economical. In our The Science of Coffee courses we go from the ground to the cup and teach them how to do traceability. Then, a producer can do chromatography to know if his soil is good and how to make corrections,” says Julián.
For this type of qualitative analysis you need:
- paper filter
- Sensitizing agent
- Extracting agent
According to Julián’s calculations, the costs of these elements are approximately US $1 per chromatography. That is, a manageable and accessible value for producers .
The importance and uniqueness of Pfeiffer chromatography
The most common thing when talking about chromatography in the coffee industry is to analyze soil, manures and fertilizers, especially when talking about paper chromatography. That is the first line of work of its inventor, Ludwig Pfeiffer.
With this technique, patterns or circular chromatograms are obtained on previously conditioned filter paper. Thanks to this, it is possible to know if the coffee has been contaminated or has been added with any substance other than those found in the terroir.
It even shows if it has been contaminated with pesticides, for example, or if it does not comply with organic processes and standards , whether in green, roasted or cup beans.
“Pfeiffer developed this chromatography that in particular allows us to understand and interpret in a simple way the state of the soil with pre-existing patterns. Afterwards, it is done in the coffee to see if what is in the soil is being assimilated by the plant.” says Julián.
“There are many types of chromatographies but they are difficult to develop, to access due to cost, while this one is simple, simple and allows us traceability from the soil to the cup , or from the soil to our table.” he highlights.
What does the chromatography of the cup say?
In paper chromatography, for now, it is not possible to isolate the elements corresponding to the flavor notes in the cup but in other variants, such as gas chromatography, they can be identified. A common feature of any chromatography is that it allows the coffee grower to know the different elements present in his terroir and that opens up a panorama of possibilities to accentuate some aspects and moderate others.
So, how to use chromatography to influence cup quality? According to Julián, it serves to explore the terroir and the type of production, organic or conventional, that the coffee grower can apply.
Regarding the differentiation in cup, he explains that it is already a little more complex; However, “when they are coffees that have been forcibly differentiated , it is very easy to identify them because the added compounds are structurally different and appear in very high concentrations. As they are not natural to the plant, the difference in the observed pattern is noticeable.”
For his part, Hernán, based on his experience with gas chromatography, says: “I think that the great challenge for a coffee grower is to always be able to replicate a good cup or always have the same profile. For this, standards are created within the post-harvest process and that is where chromatography comes in as a tool that can be very useful to suddenly find some difference in the decisions that were made.”
Julián, who even offers training in this regard through his company, concludes by saying that “when a fermentation is carried out in which control is lost, the chromatography pattern is one and when it is a fermentation for which there is control, the pattern is one other”. Consequently, chromatography, as a tool, can be used for many purposes.
Chromatography is a very interesting method to learn more about coffee and to understand, from a scientific perspective, the elements that have an impact on the final results in the cup.
Although in some cases it may be out of the reach of producers, there are options to do it in a more artisanal way and that also offer relevant information. With preparation, study and training it is possible to get the best out of these techniques and translate their results into changes or improvements in coffee production.
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