What Are Decaf Coffee Beans? Recommended Low-Caffeine Coffee Beans and Where to Buy Them in Guangzhou

The History and Effects of Caffeine

As early as the Stone Age, humans had already begun using caffeine. Early people discovered that chewing the seeds, bark, or leaves of certain plants reduced fatigue and refreshed the mind. Only many years later did people discover that brewing these plants in hot water could increase the effectiveness of the caffeine. Many cultures have myths about ancient people discovering these plants.

Understanding Caffeine

Caffeine is an alkaloid found in natural beverages such as hot cocoa, post-workout functional drinks, cola, coffee, and tea, all of which contain certain amounts of it. Even in nature, most plants contain this substance. Caffeine has the effect of stimulating the central nervous system and temporarily restoring physical strength.

Caffeine is a central nervous system stimulant and a metabolic stimulant. It is used both as a beverage and as a medication, and its effects are to refresh and relieve fatigue. The precise dose needed to produce effects varies from person to person, mainly depending on body size and caffeine tolerance. Caffeine can begin to take effect in the body in less than an hour, and for a moderate dose the effects disappear within 3 to 4 hours. Consuming caffeine does not reduce the amount of sleep a person needs; it only temporarily weakens the feeling of drowsiness. Because of these effects, caffeine acts as a performance enhancer, improving the capabilities of the brain and body.

For humans, caffeine is safe, but it is toxic to certain animals, such as dogs, horses, and parrots, because those animals' livers break caffeine down far less effectively than the human liver does. Caffeine also has significant effects on spiders, far exceeding those of other drugs, so here is a reminder: do not give your coffee to a pet dog.

Caffeine Content in Coffee Beans

Generally, among the two major coffee bean species, Arabica beans have the lower caffeine content, containing 1.1% to 1.7% caffeine, while Robusta beans contain 2% to 4.5%. Decaffeinated coffee is regulated to have a caffeine content not exceeding 0.3% in brewed coffee. This means that a cup of decaf must contain no more than 5 milligrams of caffeine to be called decaffeinated coffee beans, or decaf coffee.

Decaffeination Processes

The processing steps for decaffeinated coffee beans must be carried out while the beans are in their raw state. Currently there are three main methods for removing caffeine: the traditional or European process (European Process), the Swiss Water Process (SWP), and the supercritical carbon dioxide process (CO₂ Process). These three methods can effectively remove most of the caffeine, leaving only 2 to 3% of the original caffeine content in the beans.

There are three main ways to remove caffeine, and removing caffeine reduces coffee flavour.

1. European (Solvent) Processing

There are two subdivisions:

1. Direct solvent method. Steam opens the pores of the raw beans, a caffeine solvent is sprayed on directly, and the "steaming" method continues to remove the solvent and the caffeine.

2. Indirect solvent method. Raw beans are soaked in hot water, extracting everything that can be dissolved. The water and the beans are separated. A solvent is used to extract the caffeine from the hot water, and the remaining "flavour" is sprayed back onto the now bland bean shells.

This method generally uses dichloromethane, a relatively common organic solvent of lower toxicity. Soaking raw coffee beans in a dichloromethane solution causes the caffeine in the beans to dissolve into the solvent, separating it from the coffee. In the end, when the beans are removed, the solution cannot be completely taken away and some residue remains. However, dichloromethane has a very low boiling point (40°C), so the residue is easily removed by heating, and that temperature is far below coffee roasting temperature. The safety of the direct-contact method is therefore internationally recognised.

2. Swiss Water Processing

This is a commercially developed, highly efficient processing method with two main steps.

In the raw bean state, the beans are poured into hot water. At this point the hot water removes almost all the flavour factors from the raw beans, including the caffeine. This first batch of raw beans is discarded and not used. Afterwards, the hot water carrying all the flavour factors is filtered through activated carbon to remove the caffeine, leaving hot water full of pure flavour factors. In the Swiss Water Process this water is called "flavor-charged water." It contains saturated flavour factors that should be present in raw coffee beans, lacking only caffeine, and this special water is the most important medium in the subsequent decaffeination process.

A new batch of raw beans is soaked in flavor-charged water that contains flavour factors but no caffeine. The beans release caffeine but do not release flavour factors, so the original flavour of the raw beans is not significantly diminished. Obviously, the flavour factors in the flavor-charged water are already close to saturation, so they cannot dissolve more flavour, but there is still plenty of space to dissolve caffeine.

After the raw beans go through this decaffeination and flavour-preservation process, they are directly dried and sold. The flavor-charged water that has absorbed caffeine can be repeatedly filtered through activated carbon to remove the caffeine and be reused.

The method relies mainly on flavor water already full of coffee flavour components but without caffeine. The caffeine in the fresh beans diffuses into the water. Theoretically the flavour will not be lost, but in reality, as anyone who has tasted it knows, there is definitely some loss.

3. Supercritical Carbon Dioxide Processing Method (CO₂ Process)

The supercritical carbon dioxide process involves soaking raw coffee beans in liquid carbon dioxide. Under high pressure, carbon dioxide takes on a semi-gaseous, semi-liquid state. In this state, carbon dioxide can actively combine with caffeine, and the caffeine is finally filtered out through a suction-type activated carbon filter.

Understanding Decaffeinated Coffee

Actually, decaffeinated coffee beans are simply coffee beans that have gone through a special process to bring the caffeine content below 1%. In the other stages of picking, processing, roasting, and brewing, there is no difference between them and non-decaffeinated beans, apart from one extra step during raw-bean processing.

Theoretically, the flavour of decaffeinated coffee should not be lost to any great extent. In reality, though, this does not mean that the decaffeinated and non-decaffeinated versions of the same bean taste exactly the same; there is still a significant difference in taste after decaffeination, especially a noticeable decrease in body. It simply means that if a bean has herbal or citrus flavours, the decaffeinated version will keep those herbal or citrus flavours too.

As for the flavour of decaffeinated coffee, I can only say it is unimpressive. Even when special methods are used to extract and filter the caffeine, they still take away some flavour factors, which likely leaves decaf with an unsatisfying flavour. Decaffeinated coffee tastes relatively light, with a less prominent aroma, which I do not particularly like. I still prefer regular coffee beans. In fact, a few cups of coffee's caffeine a day is not harmful to ordinary people, aside from special groups. There is really no need... As the saying goes, you cannot have your cake and eat it too. Since what is needed is decaffeinated coffee, flavour has to be sacrificed.

(The processing method information above is sourced from Kenneth Davids' "Home Coffee Roasting, Revised, Updated Edition: Romance and Revival" (2003).)

Health Benefits of Caffeine

The following information is sourced from Baidu Encyclopedia, to illustrate that moderate caffeine is beneficial to human health. Interested readers can refer to it.

Health Value

The currently known specific components of caffeine and their physiological effects on the human body are as follows:

1. Antioxidant Protection

It can effectively resist the free radicals that threaten our health. Free radicals are the main cause of many diseases, such as cardiomyopathy, arteriosclerosis, stroke, emphysema, and Parkinson's disease. Excessive free radicals can affect body metabolism, damage cells, and consequently affect organs and tissues.

2. Cardiovascular Protection

Coffee contains high levels of polyphenolic compounds, a powerful class of antioxidants that can delay the oxidation of low-density lipoprotein by up to three times. They can dissolve blood clots and prevent thrombosis; coffee can also enhance vasoconstriction, avoiding the vasodilation that causes headaches. In addition, small amounts of coffee can enhance myocardial contractility, promote blood circulation, and help prevent cardiovascular disease.

3. Mental Alertness

Caffeine stimulates the central nervous system of the brain, prolongs brain wakefulness, makes thinking clear and sharp, and improves concentration, which can increase work and learning efficiency.

4. Anti-depression

Small amounts of caffeine can make people feel refreshed and happy and relieve depression.

5. Weight Management

Caffeine can increase the rate at which the body consumes calories. One study found that 100 milligrams of caffeine (about 1 cup of coffee) can accelerate fat breakdown and increase the body's metabolic rate by 3 to 4 percent, increasing calorie consumption. Moderate consumption has weight-loss effects.

6. Digestive Support

Caffeine stimulates the sympathetic nervous system and increases gastric juice secretion. Moderate consumption after meals aids digestion.

7. Diuretic Effect

Coffee has diuretic properties and can increase urine output, thereby increasing the frequency of urination.

8. Constipation Relief

Coffee can stimulate gastrointestinal hormones or peristaltic hormones, producing a laxative effect, and can serve as a quick laxative.

9. Cancer Risk Reduction

It may reduce the risk of colon or rectal cancer: coffee contains natural antioxidants.

10. Pain Relief

When used as a medication, caffeine can enhance the effects of certain pain relievers.

11. Enhanced Physical Agility

Caffeine also helps during exercise by lowering exercise thresholds, increasing physical agility, and enabling athletes to achieve better performance.

12. Reduced Risk of Gallstones

A recent study from the Harvard School of Public Health indicates that people who drink 2 to 3 cups of coffee daily have, on average, a 40% lower chance of developing gallstones compared with those who never drink coffee. In addition, the tannic acid in coffee has astringent, hemostatic, and deodorising effects.

FrontStreet Coffee Recommendation

If you want to lower your caffeine intake without switching to decaf, the simplest route is to drink Arabica, which carries 1.1% to 1.7% caffeine versus Robusta's 2% to 4.5%. FrontStreet Coffee's PWN Indonesia Golden Mandheling is a wet-hulled, dark-roasted Sumatra G1 that is hand-sorted three times, with herbal, spice, and woody notes and a full, sweet body, and it works in a moka pot, pour-over, drip bag, or latte. For a fruitier cup, FrontStreet Coffee's Sun-Dried Huakui is an Ethiopia Sidamo natural with elegant florals and ripe tropical fruit such as cream strawberry, mango, jackfruit, citrus, and blueberry, the same lot style that won first place in that year's TOH green-bean competition. If you want a bright, clean washed option, FrontStreet Coffee's Guodingding Cooperative is an Ethiopia G1 washed Yirgacheffe, medium-light roasted for white florals, citrus, orange, and green-tea notes.