Java Beat: How Is My Coffee Decaffeinated?
This article originally published in The Sturbridge Times, September 2017
By Elvis Dyer, Owner/Roaster, Sturbridge Coffee Roasters
Many people enjoy drinking coffee, and some want to limit their caffeine intake. For those people, decaffeinated (decaf) coffee is a great alternative. Yes, there is caffeine in decaf. Depending on the brand, decaf coffee can range between 3 to 12mg per 8 ounces. In the United States, federal regulations require that to label coffee as “decaffeinated” that coffee must have had its caffeine level reduced by no less than 97.5 percent. There are many ways to remove caffeine from coffee beans, and all include: water, solvents or carbon dioxide and all occur when the beans are in their green state, prior to being roasted.
Decaffeinated processes generally falls under two methods: solvent-based or non-solvent based.
Solvent Based Decaffeinated Process:
Solvent based processes involve the caffeine being removed from the beans with the help of a chemical solvent. Early decaffeination processes included a list of toxic solvents such as benzene, trichloroethylene (TCE), dichloromethane and even chloroform, however, more recently, methylene chloride and ethyl acetate have been used. This solvent process can be done either via a “direct” method or “indirect” method. Typically, if a process is not named for a decaffeinated coffee, it has been treated by either the direct or indirect solvent methods. It is estimated that up to 70% of all coffee is decaffeinated with the help of solvents.
In the direct–solvent based process, the beans are steamed for about 30 minutes to open their pores. They are then repeatedly rinsed with a solvent for about 10 hours to remove the caffeine. The caffeine-laden solvent is then drained away and the beans are steamed again to remove any residual solvent. Most of the time the solvent of choice in this method is ethyl acetate, and the process if often referred to as “the natural decaffeination method” or “the Ethyl acetate method.”
In the indirect-solvent method, the coffee beans are soaked in near boiling water for several hours, which extracts the caffeine and some flavor elements and oils from the beans. The water is then separated and transferred to another tank where the beans are washed for about 10 hours in solvent. The molecules of the chemical solvent selectively bond with the molecules of caffeine and the resulting mixture is then heated to evaporate the solvent and caffeine. Lastly, the beans are reintroduced to the liquid to reabsorb most of the coffee oils and flavor elements. This method is very popular in Europe, especially in Germany, and primarily uses methylene chloride as solvent. It is often referred to as “KVW method” (short for Kaffee Veredelugs Werk), “the European method,” “methylene chloride method,” or “Euro Prep.”
Non-Solvent Based Decaffeinated Process:
Water-based decaffeinated process, also known as Swiss Water Process, SWP Method, Activated Charcoal Decaffeination or Dihydro-oxide Process, is a chemical-free, water decaffeination process pioneered in Switzerland in 1933 and developed as a commercially viable method of decaffeination by Coffex S.A. in 1980. In 1988, the Swiss Water Method was introduced to the market and its facility is based near Vancouver, British Columbia, Canada. The Swiss Water Company’s decaffeination facility is certified organic by both OCIA and Aurora Certified Organic and they are also certified Kosher by the Kosher Overseers Association. Swiss Water Process uses the elements of water, temperature and time and does not directly or indirectly add chemicals to extract the caffeine. This process relies on solubility and osmosis to decaffeinate coffee beans. This method is almost exclusively used for decaffeination of organic coffee. The green beans are cleaned and hydrated with pure, local water to prepare them for caffeine extraction. An internally developed Green Coffee Extract (GCE) is introduced to the beans and caffeine removal begins. Caffeine ventures out on its own, away from the coffee beans into the GCE until the ratio of soluble compounds in the GCE to the compounds in the coffee reach the point of equilibrium. Caffeine and GCE flow continuously through our proprietary carbon filters until all the caffeine is trapped and separated from the GCE. Then the GCE is refreshed so that it can be used again and again to remove more caffeine. The process and caffeine levels in each batch decaffeinating is monitored for hours; monitoring time, gauge temperature controls, and the levels on the GCE flow. The result is decaffeination without a massive loss of flavor and 99.9% caffeine-free coffee.
The carbon dioxide decaffeinated process, also known as CO2 (or Carbon Dioxide) Method, Liquid Carbon Dioxide Method, Supercritical Carbon Dioxide Method is the most recent method. It was developed by Kurt Zosel, a scientist of the Max Plank Institute, and uses liquid CO2 in place of chemical solvents. It acts selectively on the caffeine, releasing the alkaloid and nothing else. In the CO2 decaffeination process, water soaked coffee beans are placed in a stainless-steel container (the extraction vessel). The extractor is then sealed and liquid CO2 is forced into the coffee at pressures of 1,000 pounds per square inch to extract the caffeine. The CO2 acts as the solvent to dissolve and draw the caffeine from the coffee beans, leaving the larger-molecule flavor components behind. The caffeine laden CO2 is then transferred to another container (the absorption chamber). Then, the pressure is released and the CO2 returns to its gaseous state, leaving the caffeine behind. The caffeine free CO2 gas is pumped back into a pressurized container for reuse. Because of the high cost associated with this process, it is used primarily to decaffeinate large quantities of commercial-grade, less-exotic coffee found in grocery stores.
Whether you like your coffee with the caffeine or without it, we can all agree that nothing beats a great cup of coffee!
Our Decaf Coffee is Swiss Water Process (SWP), Mexican Organic Decaf.
Check out our fresh roasted coffees here!