Caffeine occurs naturally in more than 60 plants, including:

• the Arabica plant, which produces coffee beans
• The Theobroma cacao tree, which produces the beans that are the primary ingredient in chocolate.
• kola nuts, which many cola drink products are made with
• The Thea sinensis plant, whose leaves are used for teas.

When separated from its sources, caffeine is a white, bitter-tasting powder.
Several methods are used to remove caffeine from its natural sources:

• Methylene chloride processing
• Ethyl acetate processing
• Carbon dioxide processing
• Water processing

Methylene chloride is a chemical used as a solvent to extract caffeine from many raw materials. Molecules of caffeine bond to molecules of methylene chloride. The materials are softened in a water bath or in steam. The next step is to process the materials with methylene chloride by either of two methods:

• Using the "direct" method, caffeine is removed by directly soaking the materials in methylene chloride.
• Using the "indirect" method, caffeine, which is water soluble, is extracted by soaking the materials in water. Many of the flavors and oils are also extracted during this process, so the solution is treated with methylene chloride and then returned to the material for reabsorption of the flavorings.

Ethyl acetate processed products are referred to as "naturally decaffeinated" because ethyl acetate is a chemical found naturally in many fruits. Caffeine is extracted in the same way as with methylene chloride processing, but ethyl acetate is the solvent.

To decaffeinate using carbon dioxide (CO2), water-softened materials are "pressure cooked" with the gas. At high pressures and high temperatures, carbon dioxide is in a supercritical state, acting as both a gas and a liquid. It becomes a solvent with its small, nonpolar molecules attracting the small caffeine molecules. Since flavor molecules are larger, they remain intact, which is why this process retains the flavor of the material better.

Caffeine extraction with water is used primarily for coffee decaffeination. The process is similar to the "indirect" method used in methylene chloride processing, but no chemicals are used. After the caffeine is leached out of the material by soaking in hot water for a period of time, the solution is then passed through a carbon filter for caffeine removal. The water is then returned to the beans for reabsorption of flavors and oils. In the "Swiss Water Process," the same method is used, but instead of soaking in water, the beans are soaked in a coffee-flavoured solution. This results in the caffeine being extracted without removing the coffee flavour.

Caffeine is not removed completely using any of these methods, but under federal regulations in the United States, caffeine levels must not be above 2.5 percent of the product in order for a product to be labeled "decaffeinated."
Most of the caffeine removed in processing is manufactured for use in other products, such as medicines and soft drinks. For example, less than 5 percent of the caffeine found in cola drinks is actually from the kola nut, and many of the popular "high caffeine" soft drinks do not contain kola nut extracts at all. The caffeine content of soft drinks is primarily, and sometimes completely, from the addition of caffeine extracted from decaffeination processes.

SWISS WATER® Process 101

Lesson 1 – Bean Composition

A typical green bean is composed of:

Lesson 2 – Flavour-Charged Water

First we took some high-grown green coffee beans which were full of flavour....

 

... and immersed them in pure water.

The water extracted both the coffee flavor solids and the caffeine from the beans.

These beans were then discarded and the caffeine was removed using a carbon filter, leaving just the water, super-saturated with coffee solids.

Lesson 3: The Art of Chemical-Free Decaffeination

Flavour-charged water is integral to the SWISS WATER® Process, which starts with top quality green beans and works as follows.

First, the beans are cleaned and soaked in water, partially saturated with coffee flavor solids, in preparation for caffeine extraction.

Next, the beans are immersed in the flavor-charged water. Initially the water is caffeine-free, and as a result the caffeine diffuses from the beans into the water. Since the concentration of flavor components in the bean and in the water is equal, only the caffeine is removed, leaving the flavor intact. The water then passes through a carbon filter that traps the caffeine. The now caffeine-free, flavor-charged water flows back to the beans to remove more caffeine. This process continues for approximately 8 hours, until the beans are 99.9% caffeine-free.

Following decaffeination, the trapped caffeine is removed from the carbon filter. The flavor-charged water is then recycled to the start of the process for the next batch of beans.

A typical green bean, after decaffeination, is composed of:

Chemical Decaffeination Processes

What chemicals do other decaffeination processes use?

The majority of decaf coffee, about 80%, is decaffeinated with a chemical decaffeination method using chemicals like methylene chloride or ethyl acetate.

How does the chemical decaffeination processes work?

1. Beans are soaked in a caffeine absorbing solvent.
2. The solvent, now containing the caffeine, is separated from the beans.
3. The caffeine is removed from the solvent.
4. Steps 1-3 are repeated until sufficient caffeine is removed from the beans.

How are chemicals used in these processes?

There are two types of chemical caffeine removal processes: direct and indirect.

Direct process: The chemicals are used in steps 1 and 2 as the caffeine absorbing solvent.

Indirect process: The chemicals are used in step 3 to remove the caffeine from the solvent (a liquid composed primarily of water).

The terms “water process”, “natural process”, and “European process” are sometimes used to describe decaffeination processes. In fact, all three terms often refer to decaffeination processes that use chemicals.

Caffeine and Coffee

Caffeine is a natural substance that is present in the leaves, seeds and fruits of more than sixty plant species worldwide. Many food and beverage products made with these ingredients inherently contain caffeine. In addition, caffeine is sometimes added to foods and beverages during the manufacturing process in order to enhance flavor, or in the case of medications, to enhance efficacy.

Factors that Affect the Caffeine Level in Coffee

Each of the following can slightly alter the level of caffeine in decaffeinated coffee so that it is above or below the typical caffeine level.

1. blend composition
2. brewing extraction rates
3. grind
4. roast color
5. water temperature
Higher extraction rates, warmer water, a finer grind, and a lighter roast all result in a higher caffeine level in decaf coffee. Potentially, the caffeine level could increase from approximately 2 mg to 6 mg per cup. This is a negligible increase relative to a caffeinated cup of coffee, which contains between 60 to 180 mg of caffeine per cup.

Caffeine and Espresso

An espresso blend is defined by the grind size and the low level of water used in its preparation. The same green decaffeinated coffee beans are used for espresso and a regular cup of decaffeinated coffee. Decaf espresso will tend to have a higher concentration of caffeine compared to regular decaf coffee due to its much finer grind and the relatively lower amount of water used in its preparation.

Equipment Maintenance

Proper precautions need to be taken in cleaning machines prior to grinding decaffeinated beans or brewing decaf, to avoid a contamination issue due to any remaining regular caffeinated beans. However, the potential always exists for simple operator error. Ultimately, the operator must be able to separate regular from decaf.

Caffeine Content in Common Foods and Beverages

Product	Caffeine Content	Product	Caffeine Content
Regular coffee (drip method, 5 oz)	60 – 180 mg	Tea, loose or bags (5 oz)	20 – 90 mg
Regular coffee (percolated, 5 oz)	40 – 170 mg	Iced Tea (12 oz)	67 – 76 mg
Regular coffee (instant, 5 oz)	30 – 120 mg	Hot Cocoa (5 oz)	2 – 20 mg
Decaffeinated coffee (drip method, 5 oz)	2 – 5 mg	Coca Cola (12 oz)	46 mg
Decaffeinated coffee (instant, 5 oz)	1 – 5 mg	Pepsi (12 oz)	38 mg
Espresso (1 oz)	30 – 50 mg (1 oz)	Milk chocolate (1 oz)	1 – 15 mg

Source: US Food and Drug Administration and National Soft Drink Association