How Does the Swiss Water Process Change an Arabica Coffee Bean?

Decaf coffee is not caffeine-free. Standard arabica coffee bean ranges hold roughly 0.9 to 1.4 percent caffeine by weight, averaging about 1.2 percent, and decaffeination reduces that to a small residue rather than zero. The Swiss Water Process removes caffeine using water, temperature, and a carbon filter, without chemical solvents.

The starting point matters as much as the method. A Colombian green coffee bean from the Huila region, washed and sorted for grade, gives the roaster clean acidity and sweetness to work with. Roasting usually runs a little darker or slower than the same lot would be roasted with caffeine intact.

Decaf coffee has gradually entered the public eye in recent years, becoming a choice for consumers who want to drink coffee without taking in too much caffeine. But many people still have questions about decaf coffee: does it really contain no caffeine? Will the decaffeination process make the coffee taste bad? Front Street Coffee has listed a Swiss Water Process decaf coffee bean from Colombia's Huila region. This article will comprehensively analyze the differences in taste and flavor between decaf coffee and regular coffee from aspects such as the definition and standards of decaf coffee, the principles and characteristics of various decaffeination processes, green bean varieties and grades, roasting curves, and brewing suggestions, helping coffee lovers better understand the true face of decaf coffee.

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Today, coffee's role in people's lives has long gone beyond being merely a refreshing drink; it represents more of a lifestyle. The introduction of decaf coffee provides an ideal alternative for people who are affected by sleep due to caffeine intake, or who love the flavor of coffee but do not want to consume caffeine.

However, after decaf coffee was created, many people also raised questions, worrying about whether it might affect health. Front Street believes that discussing health risks apart from intake amount is not scientific. Whether caffeinated or decaf coffee, as long as daily consumption exceeds the range the human body can tolerate, even drinking water can cause problems. Therefore, Front Street also reminds all coffee lovers that although coffee is good, it should still be consumed in moderation. Back to the point, what exactly is decaf coffee, and how is it made? For this reason, Front Street specifically acquired and listed a Colombian decaf coffee bean to explore its mysteries together with everyone.

What is decaf coffee? Does decaf coffee really have zero caffeine?

Usually, the caffeine content of coffee beans is measured by weight ratio. The caffeine content of Arabica is between 0.9% and 1.4% (average about 1.2%), while Robusta is between 1.8% and 4% (average about 2.2%). Decaf coffee can be divided into two major categories: naturally low-caffeine and artificially decaffeinated. Among them, the most representative naturally low-caffeine coffee is Bourbon Pointu (Coffea Laurina), whose caffeine content is only about half that of regular Arabica (about 0.6%).

Bourbon Pointu is different from coffee that has undergone artificial decaffeination. Due to genetic degeneration, its caffeine content is naturally lower than that of ordinary Arabica coffee trees, and its flavor performance is even better. As for decaf coffee after artificial decaffeination, the standard set by the European Union requires that the caffeine content after processing must not exceed 0.1% of the weight of green beans, while the standard of the U.S. Food and Drug Administration FDA is to remove caffeine to less than 3% of the original content.

Does decaf coffee mean it contains no caffeine at all? The answer is no. Front Street Coffee (FrontStreet Coffee) points out that although decaf coffee removes most of the caffeine, about 2% to 3% of caffeine still remains, which means each cup of decaf espresso still contains about 0 to 7 milligrams of caffeine. Although a trace amount remains, compared with regular espresso, the caffeine contained in decaf coffee will not have any noticeable effect on the vast majority of people.

How is caffeine extracted from decaf coffee?

With the continuous development of the coffee market, there are now many options for decaffeination processes, which can broadly be classified into direct or indirect solvent processes, supercritical carbon dioxide processes, the Swiss Water Process, and the mountain spring water process.

Direct solvent process (direct contact method)

The direct solvent process uses chemical solutions such as dichloromethane and ethyl acetate to dissolve out caffeine. In operation, steam is first used to open the pores of green coffee beans, then dichloromethane solvent is introduced directly into the coffee beans. After the solvent binds with caffeine, the caffeine-rich solvent is rinsed away, and then the coffee beans are steamed again to remove all residual solvent. Because dichloromethane is suspected of possibly increasing cancer risk through long-term exposure, using it as a solvent raises certain concerns. But in fact, the FDA limits residual dichloromethane after decaffeination to 0.001%, and actual levels are often even lower, so side effects are extremely limited.

If ethyl acetate is used as the solvent, the process is the same as above. Ethyl acetate usually comes from sugarcane, so when this method is used, the direct solvent method is sometimes also called the sugarcane decaffeination method. Colombian decaffeination usually uses this method. However, it should be noted that ethyl acetate is a highly flammable substance, so the operation is relatively dangerous.

Swiss Water Process

This is one of the most traditional caffeine extraction methods and also one of the more efficient processing methods in commercial development.

The specific steps of the Swiss Water Process are as follows: first soak green coffee beans in hot water. This hot water is called "Flavor-charged Water" in the Swiss Water Process. This water has already been saturated with all the flavor factors that should be present in the green coffee beans, except that it contains no caffeine. This special water is the most critical medium in the subsequent decaffeination procedure. After the flavor-charged water is formed, the coffee beans are filtered out, and then an activated carbon filter is used to filter the caffeine out of the flavor-charged water. What remains is hot water full of pure flavor factors. The filtered coffee beans are then soaked again in this hot water so that the coffee beans reabsorb the coffee flavor.

Supercritical carbon dioxide process

This process first allows the coffee beans to absorb water and expand, making the caffeine molecules loose within the bean body. Then liquefied carbon dioxide is added, and an environment of more than 100 atmospheres is created in the water. Carbon dioxide is highly selective and will not destroy the carbohydrates and proteins in the coffee beans while dissolving caffeine, thereby ensuring that the flavor of the coffee beans is not damaged. The liquid carbon dioxide carrying caffeine can also be recycled and reused after the caffeine is removed.

Coffee made with carbon dioxide decaffeination places less burden on the human body, and studies show that this method extracts more caffeine than the direct solvent method, but at the same time, the cost of this method is also considerably higher than that of the direct solvent method.

Mountain spring water process

Quite similar to the Swiss Water Process, this method uses another special kind of water, namely water taken from glaciers, to extract caffeine. Descamex states that it uses some kind of special filtration device to remove caffeine. After treatment, a caffeine-free water-based solution is obtained. This solution also dissolves the coffee's solid substances and can be reused in subsequent decaffeination procedures.

Does decaf coffee taste bad?

Based on the various decaf coffee processing methods above, Front Street Coffee (FrontStreet Coffee) believes that the reason decaf coffee does not taste good is not caused by the processing itself. The reason is that most decaf coffee uses some low-priced commercial-grade coffee beans at the raw material selection stage. Modern decaffeination technology is actually quite complex, but in most cases, companies producing decaf coffee tend to choose varieties with high caffeine content (such as Robusta beans) when selecting raw materials. These coffee beans themselves already have unsatisfactory flavor before decaffeination. Just like other coffee beans sold in coffee shops, if decaf coffee beans are selected from high-quality Arabica coffee beans from the beginning, then even after decaffeination, decaf coffee can still show quite good flavor performance.

Front Street Coffee (FrontStreet Coffee) representative coffee bean — Colombia Huila Swiss Water Process Decaf

Country of origin: Colombia

Region: Huila

Altitude: 1,750 meters

Varieties: Typica, Caturra, Castillo

Processing method: Swiss Water Process

Grade: Supremo

Harvest season: 2020

Colombia Huila region

Colombian coffee beans enjoy a very high reputation worldwide, and the high-quality washed beans produced there have long been regarded as the benchmark for high-quality coffee. Coffee beans exported from Colombia must undergo multiple strict inspections, including specific gravity testing and manual removal of defective beans, before they can be bagged, so the quality of Colombian coffee can be fully guaranteed.

Colombia Huila belongs to the specially selected high-mountain coffee beans of the Colombian state-owned company and is known as a national treasure-level product of Colombia. Thanks to superior geographical and climatic conditions, Colombian coffee has always maintained a relatively high quality standard. Usually, Colombian coffee beans without a special market trademark name all come from the National Federation of Colombia Coffee Growers, an organization long known for strict quality control and active promotion.

Colombian decaf coffee bean varieties

This batch of decaf coffee includes three coffee varieties: Typica, Caturra, and Castillo. Typica, as one of the oldest Arabica varieties in the world, is favored for its delicious and sweet flavor, but due to its relatively low yield per unit, it has been replaced by many high-yield coffee varieties in Colombia. Caturra is a natural mutation of Bourbon. Its flavor is comparable to or slightly inferior to Bourbon beans, but it has extremely strong adaptability and does not need shade trees. It can grow vigorously even when directly exposed to the sun, commonly known as Sun Coffee, and can adapt to high-density planting.

Castillo is based on the Colombia variety and was crossbred with Caturra, and was finally successfully bred only by the tenth generation. Although it was not favored by industry insiders when first launched, in recent years many batches with elegant and delicate flavors have also emerged on the market.

Green bean grade

The grade of this batch of green coffee beans is Supremo. In Colombia's coffee bean grading system, Supremo represents the highest grade, while Excelso has smaller beans and is more ordinary in quality. Colombian coffee beans have a balanced flavor profile, a rich taste, unique flavor characteristics, and relatively full body. At medium roast, the flavor carries a little sweetness of vanilla and dark chocolate.

How Front Street roasts Colombian decaf coffee beans

Front Street's roaster uses medium heat and a steady climb. The yellowing point is about 6 minutes 15 seconds, after which the heat is lowered and the damper is opened to enter the Maillard reaction stage. At first crack, the damper is opened wide, the heat is maintained, the temperature is about 183.2°C, and the beans are discharged 2 minutes 30 seconds after first crack.

Preheat the roaster to 200°C and charge the beans, set the damper to 3, turn on the heat after 30 seconds, adjust the heat to 130, the turning point is 1 minute 32 seconds, maintain the heat, yellowing at 6 minutes 15 seconds, the grassy smell disappears, entering the dehydration stage, raise the heat to 140, open the damper to 4, and when it reaches 151°C lower the heat again to 110.

Dehydration is completed at 8 minutes, wrinkles and dark streaks appear on the bean surface, and the toast aroma turns into coffee aroma. This is the prelude to first crack. At this time, keep the heat unchanged, open the damper to 5, and pay attention to listening for the sound of first crack. First crack begins at 9 minutes 57 seconds, damper fully open to 5. Post-first-crack development time is 2 minutes 30 seconds, and the beans are discharged at 194.2°C.

Front Street cupping report

Front Street brewing suggestions

Dripper: Kono dripper

Water temperature: 90°C

Coffee dose: 15g

Coffee-to-water ratio: 1:15

Grind size: medium-coarse grind (70% passing through China standard No. 20 sieve)

Brewing method: three-stage extraction. Use 30 grams of water for blooming for 30 seconds, then pour in a small stream in circles until 125 grams for the stage break. When the water level drops and is about to expose the coffee bed, continue pouring until 225 grams and stop pouring. When the water level drops and is about to expose the coffee bed, remove the dripper. The brewing time is 3 minutes.

Brewed flavor: dark chocolate, caramel, nuts, full-bodied.

The above content is compiled by CoffeeHunters, a coffee news website.