How did coffees come to be decaffeinated then? For this, we may have to thank Goethe, the German poet and statesman, who requested the chemist Runge to examine coffee in the same way that Runge had examined the properties of Belladonna extract. Runge went on to achieve success in this endeavour, isolating and discovering caffeine from coffee c.1820
The Cafe H-A-G brand was the first commercially available decaffeinated coffee, introduced c.1906 after another German scientist Ludwig Roselius and his team patented a process involving soaking green coffee beans in various acids and bases and then using Benzene as a solvent to remove the caffeine.
The principles involved in removing caffeine from coffee remain largely unchanged to this day, but thankfully, modern methods rely far less on chemicals such as Benzene (which is today recognised as a carcinogen) to achieve the desired result, whilst preserving the intrinsic coffee flavour as much as possible. These methods are all variations on and refinements of Roselius’s original method. Popular methods today include those which use organic compounds such as dichloromethane, triglycerides and ethyl acetate as the solvent. Other methods, even more refined, rely on a combination of water, green coffee extract and charcoal (Swiss Water) or, as in the case here, water and pressurised carbon dioxide (Sparkling Water).
The Sparkling Water method uses supercritical carbon dioxide as a means of decaffeination. It was developed by Kurt Zosel, a scientist at the Max Planck Institute in 1967, and further refined by the CR3, a German decaffeination company in 1988. It uses carbon dioxide, heated and pressurised above its critical point, to extract caffeine.In this process, green coffee beans are steamed and then added to a high pressure vessel. A mixture of water and carbon dioxide is circulated through the vessel at 300 ATM and 65°C. At this temperature and pressure carbon dioxide is a supercritical fluid, with properties midway between a gas and a liquid. Caffeine dissolves into the carbon dioxide; compounds contributing to the flavour of the brewed coffee are largely insoluble in carbon dioxide and remain in the bean. In a separate vessel, caffeine is scrubbed from the carbon dioxide with additional water. The carbon dioxide is then recirculated to the pressure vessel, until the desired caffeine content is reached, typically resulting in at least a 97% drop in caffeine. For reference, a typical 8oz cup of regular arabica coffee contains around 200mg of caffeine, whilst an 8oz cup of decaffeinated arabica would contain around 6mg of caffeine.
The decaffeination process by definition leads to the cellular structure of green coffee to be slightly compromised. For this reason, the best decaffeinated lots tend to be higher grown washed arabicas, which have higher bean density to begin with and so can handle the decaffeination process better and are able to stand up to the post-decaffeination roasting process better as well. Which brings us to the Rwandan trading company which supplied the high-grown coffee for this lot.
The Muraho Trading Company helps affiliate co-operatives increase their quality of production, fetch a higher price for their coffee, and introduces them to new markets. Muraho run washing stations are located in the Nyamasheke, Gakenke, and Nyabihu regions of Rwanda. Red Bourbon arabicas grown by local smallholder farms at an altitude of 1650-2000 MASL from, are aggregated and sorted at one of these washing stations. This assemblage of coffees from across Muraho’s washing stations is then shipped to CR3 Kaffeeveredelung Hermsen, Bremen, Germany for the removal of caffeine. CR3 is renowned for its natural CO2 decaffeination process, a method that retains much more of the flavour and aroma compounds inherent in green coffee than the more aggressive methods used in the past.
Roasted for espresso only, this decaffeinated coffee is soft, sweet, and medium-to-full bodied, with crisp acidity. Shots need to be pulled slow and long, with the resulting espresso delicious in its own right, and also working beautifully in all manner of milk and alternative milk drinks. Don’t be taken aback by coffee oils appearing on the bean surface. The weaker structural integrity of decaffeinated beans causes natural coffee oils to appear onto the surface much more readily, even at a medium roast.
Flavour notes of cocoa, molasses and dried figs form the basis of this coffee, with a moreish, slightly bitter almondine note present throughout. A crisp, hoppy finish lends acidity to this mix, which complements and lifts the other flavours present to make a superb, well-rounded coffee. This coffee would also work well brewed through a Moka Pot, aeropress or cafetiere. We are proud to present this 83+ point scoring specialty lot - but with most of the caffeine taken away, so you can enjoy drinking coffee throughout the day - full of taste and nuance, but without any of the jitters!