Have an important impact on taste and flavor: how to ensure the consistency of coffee fermentation processing?

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Bread, wine, cheese, yogurt, chocolate, coffee: what do all these delicious foods have in common? That is, they all go through the process of "fermentation".

In coffee, fermentation is essential. It can not only remove pectin, but also have a lot of effect on taste and flavor. During coffee processing, controlling fermentation means that you can improve the quality and consistency of coffee beans.

However, the process of fermentation is very complicated. For farm management, it can be a challenge. To learn more about how manufacturers deal with this problem, I talked to experts at Lallemand, a company that specializes in food and beverage fermentation.

Coffee beans fermented on an elevated bed. Photo Source: Capricornio Coffees

What is the fermentation of coffee?

Fermentation is a natural process in which microorganisms such as yeast (Saccharomyces cerevisiae "Saccharomyces cerevisiae") and bacteria (Lactobacillus) consume and metabolize sugar in coffee cherries. Lipids, proteins and acids in sugars are degraded and converted to alkyd.

But why do we ferment coffee beans? First of all, for washed coffee beans, pectin must be removed mechanically.

Francine Vidal is the coffee project manager for Lallemand LALCAFE. Lalleman is the department that provides yeast and bacteria that control the fermentation of coffee. The company offers several types of yeast, ranging from taste to acidity and specific fruit or flower flavors that have different effects on the flavor of coffee. "during the fermentation or soaking of coffee, yeast can degrade pectin in beans." Francine told me, "this process is called degumming."

However, she also explained that fermentation is important because it affects the flavor and aroma that appear in the cup test.

"Pectin consists of sugars, amino acids, aroma precursors, etc." She told me, "so, if you want to show the aroma of a coffee bean, you have to pay attention to the process."

Remember how sugars and acids decompose during fermentation? It is these reactions that make up the flavor of coffee beans. If sugars and acids are decomposed in a controlled environment, the flavor and aroma produced in beans will be more satisfactory in the appropriate temperature and time range.

Coffee fermentation in the process of washing. Photo Source: Capricornio Coffees

Good and bad coffee fermentation

Francisco Quezada is the CEO of Montenegro Farm in Guatemala. He told me, "through good fermentation, you can show the characteristics of coffee." In other words, good fermentation does not improve the quality of coffee, because the coffee itself already has the quality it should have. But we can show and maintain those flavor characteristics from this variety. "

However, fermentation is not always good. "the fermentation is not good, which will reduce the flavor of the coffee or produce a bad flavor." He stressed.

"what we find in overfermented coffee is the taste of the wine, but the taste of this wine is very bad," he said. " Even before he drank the coffee, he could recognize signs of overfermentation: the beans were reddish and emitted the indescribable aroma of rotting fruit.

Therefore, producers must understand fermentation and control it as much as possible.

Freshly picked ripe coffee cherries waiting for processing. Photo Source: Mauricio Villegas

Consistency: almost as important as quality

Luiz Roberto Saldanha, the owner of Capricornio Coffees in Brazil, told me that consistency is also essential for entering the market and rebuying.

"if you don't have a consistent product, it's very difficult to build a long-term relationship," he said. He asked me to imagine that after buying a lot of coffee, the buyer might expect to buy coffee of the same quality next time. But they didn't get the coffee beans they expected.

"at this point, it will be difficult for you to build a sustainable relationship, and your customers will no longer come to buy your coffee. Then you close the door, and it's very difficult and expensive to run it again. " Luiz explained.

One of the reasons why fermentation can be so challenging is that it is the result of chemical reactions between microbes such as bacteria, yeasts and fungi. And, according to Lallemand LALCAFE, these microbes are basically everywhere: soil, fruits and berries, and spores in the atmosphere. In different environments, their reactions will change, regulating the flavor and aroma of coffee beans in different ways.

However, the consistency of fermentation can be achieved. Mauricio Villegas, who holds a doctorate in agricultural engineering, once worked in Finca La Esperanza, Colombia, and is currently working on yeast experiments. He told me, "it's not random. Simply put, you have to define and control certain aspects to achieve more repeatability, and repeatability will lead to the same cup test flavor. "

Coffee that is drying in the sun. Photo Source: CapricornioCoffees

How to ensure the consistency and quality of fermentation

So, what factors should producers pay attention to to control fermentation and ensure consistency in order to get quality coffee?

1. The quality of coffee cherries

Margaret Fundira, the product manager at Lallemand LALCAFE, told me that the quality of the harvest was crucial. "the quality of coffee cherries is very important. Yeast can only be used with available substances to express or enhance certain aromatic compounds because their metabolic processes are different. " She said.

Luiz Roberto agrees and explains that plants need minerals, nitrogen and amino acids. "the only way to provide this is to develop a health plan to reduce stress and create better conditions to promote the growth of coffee cherries." That's what he suggested.

So, you need to make good use of everything in the wild to have a good cherry, and when I say everything, it's absolutely everything: nutrition, plague and disease management, as well as to take care of plants, water, shade and pruning.

Coffee worker in Fazenda Capricornio, Brazil. Photo Source: Capricornio Coffees

two。 Cleanliness

Microbes are everywhere, but not all of them are suitable for your coffee. Luiz Roberto explained that the coffee fruit "already has microbes adhering to the surface of the coffee through the soil, harvesting materials, workers' hands and the infrastructure for transportation, reception and processing."

These could lead to pollution, he said.

Although it is impossible to have a microbe-free farm or factory, improving cleanliness can be of great help. Sinks should be cleaned after use, as should other used tools.

3. Existence of oxygen

Mauricio told me that there are two types of fermentation: aerobic and anaerobic.

In aerobic fermentation, oxygen contributes to the respiration and growth of microorganisms. "aerobic fermentation is a traditional way of fermentation." "nevertheless, this is a fermentation process in which fermentation is less controllable," he explained. "

This is because there are microbes everywhere, and oxygen affects their growth in ways that are difficult to predict and control.

During anaerobic fermentation, Mauricio explained that coffee is usually placed in an airtight tank without oxygen, with a valve that releases carbon dioxide. This enables producers to better control the chemical reactions that are taking place in it.

Coffee beans fermented in plastic cans. Photo Source: Mauricio Villegas

4. Microorganism and yeast type

Different yeasts and microorganisms have different effects on the fermentation process. For example, Lallemand LALCAFE uses Saccharomyces cerevisiae (Saccharomyces cerevisiae) for all its products. However, depending on the strain used, yeast can have different effects on coffee: it can "enhance the fruit flavor (apricot, passionflower, flower, vanilla), the taste of coffee and the final cup test quality;" on the other hand, there is also "brightness and citrus flavor", while the third "is usually the first choice, because processing time and efficiency are the top priority."

Mauricio also told me that he had been experimenting with Lallemand LALCAFE's yeast. In his experiment, the added yeast overcame the original or natural microbes in the fermentation process, making the fermentation more controllable.

"when you add specific microbes to the fermentor, you can get higher consistency and cleaner flavor characteristics than using random species for the fermentation process, rather than not knowing what affects the fermentation." He explained.

Washed coffee beans are fermented in a tank, and the addition of yeast will affect the fermentation process. Photo Source: Lallemand LALCAFE

5. Time and temperature

These two factors are crucial because the temperature affects the rate of fermentation. "when the bean fermentation process takes place at 20 °C, the fermentation time can be as long as 36 hours," Mauricio explained.

On the other hand, at higher temperatures, he told me that fermentation tends to happen faster, usually too fast. "after 24 hours, I may have found a defective flavor in the coffee beans."

PH and temperature were measured during fermentation. Photo Source: Montenegro Farm

6. Data and records

Without recording data and processes, it will be difficult to recover the same process in the future. Each data is useful, from the temperature of the harvest season to the time of harvesting the coffee and the length of the fermentation process.

Be sure to measure the pH value, which shows how sour your coffee is. Keep track of your Bailey sugar levels, Luiz told me. It will tell you not only the amount of sugar in your coffee, but also the amount of substrate or food consumed by bacteria and yeast.

"if I don't have the data or the process, or I don't know the background, I can't do it again. So in order to be repeatable, you undoubtedly have to measure and know how variables behave in the process, "he said.

"you absolutely have to know the temperature flux or behavior during fermentation, the dynamic changes in Bailey sugar levels during fermentation, and the acidity dynamics of pectin during fermentation, because based on this, you can make a decision or even stop the treatment."

Coffee is dried on an elevated bed in FazendaCapricornio, Brazil. Photo Source: CapricornioCoffees

Each kind of coffee is different.

But remember: even if these six factors are key to maintaining the consistency of high-quality coffee, you can't treat every batch in the same way.

"some varieties can be used in different fermentation processes, whether long or short, with higher or lower temperatures, with or without microbes." Mauricio said.

So, get to know your coffee. Consider the varieties you have and the flavor they usually have. Also make sure you know your farm, from the soil to the local climate.

Luiz stresses the importance of knowing which processing methods are most effective in your area. If you work in wet or cold areas, solarization or drying may not be a good idea. "on the other hand, if you have a sunny day and a dry area with low moisture, you can get some sun exposure." He said.

"you need to understand how microbes act according to these environmental conditions, in your mind: fermentation starts with the crop and finishes in the drying process."

Coffee workers have harvested ripe coffee cherries and have been fermenting since then. Photo Source: CapricornioCoffees

Fermentation is a topic that has not been widely understood, but its effect on the quality of coffee may cause us to ignore it. Francisco told me, "We have to get rid of fear and start trying so that we can get better results and better flavor in coffee."

"this is part of the crisis in our lives." He added, "what can save us is consistency in the product, thereby improving quality through more controllable processes throughout the production chain."

After all, as Luiz said, "so why is consistency so important? Because it can aggregate the value into production, reduce the low business rate, increase the number of boutique coffee, and look for new markets. "

Translated from Perfect Daily Grind.