Decaffeination

Last week, I had a number of questions from both Partners and customers about a subject I don’t really like to talk about.  This post will deal with that and hopefully answer these questions.  The topic?  Decaf coffee.  I know, death before decaf and all that, but we do have a number of customers who require that their coffee has a minimum of caffeine. Minimum is a key word, since in North America, 97% of caffeine is removed, in Europe that figure is 99%.  I would even go so far as to suggest if the customer is under doctor’s orders to stay away from caffeine to try another beverage entirely.

Starbucks currently offers three different decaffeinated coffees.  Pike Place Decaf, Sumatra Decaf and Espresso Decaf.  On a limited time basis and usually only available at Roasterys are Reserve Decaf Costa Rica Bellavista.  Though there are four different methods used in decaffination Starbucks uses two.  With the Sumatra decaffination is achieved using the Swiss Water Method, the Pike Place and Espresso Decafs use a carbon dioxide extraction. One important item to remember is that any process employed makes the beans difficult to roast.

 

 Swiss Water Decaffination:  This particular method of decaffeination is different from what we’ve so far seen in that it does not directly or indirectly add chemicals to extract the caffeine. Rather, it relies entirely on two concepts, namely solubility and osmosis, to decaffeinate coffee beans. It begins by soaking a batch of beans in very hot water in order to dissolve the caffeine. The water is then drawn off and passed through an activated charcoal filter. The porosity of this filter is sized to only capture larger caffeine molecules, while allowing smaller oil and flavor molecules to pass through it. Consequently we end up with beans with no caffeine and no flavor in one tank, and caffeine-free “flavor charged” water (aka “Green Coffee Extract”) in another tank. And here’s where the magic happens. The flavorless caffeine-free beans are discarded, but the flavor rich water is reused to remove the caffeine from a fresh batch of coffee beans. Since this water already is saturated with flavor ingredients the flavors in this fresh batch can’t dissolve; only caffeine moves from the coffee beans to the water. So the result is decaffeination without a massive loss of flavor.

Carbon Dioxide Decaffination:  In this method of decaffeination the beans are steamed for about 30 minutes in order to open their pores. Once the coffee beans are receptive to a solvent, they are repeatedly rinsed with either methylene chloride 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. Although methylene chloride, is a solvent, its use as a decaffeination agent is not considered a health risk. While the FDA regulation allows up to ten parts per million (ppm) residual methylene chloride, actual coffee industry practice result in levels closer to one part per million. Furthermore, while it is probable that traces of the solvent remain in the decaffeinated beans it seems very unlikely that methylene chloride would survive the roasting process. This colorless liquid is highly volatile and vaporizes at 104 degrees F. Now if you take into consideration that coffee is roasted at a minimum of 400 degrees F for at least 15 minutes, and that proper brewing temperature is at about 200 degrees F, it seems unlikely that much if any methylene chloride would end up in cup of coffee.

There you have it, the two decaffeination methods employed by Starbucks, the Swiss Water Method and the Carbon Dioxide Method. Though often mocked. Decaf coffee is an important part of our product line.