What is the Swiss Water-Only Process for Decaf Coffee

FrontStreet Coffee Briefs on the Swiss Water-Only Process for Decaffeinated Coffee

Decaffeinating coffee means treating the green beans before roasting in order to separate the caffeine out of the coffee.

The biggest challenge is removing caffeine while leaving every other compound at its original concentration. That is not an easy task, because coffee has been shown to contain more than 1,000 chemical substances, and all of them are the source of its aroma and flavor.

The Swiss Water-Only Process

The Swiss Water-Only Process is a commercially developed, highly efficient method built around two main steps. The first step is to soak green coffee beans, still unroasted, in hot water. The hot water draws out almost all of the flavor compounds in the green beans, caffeine included. That first batch of green beans is then discarded. The water, now carrying all of those flavor compounds, is passed through activated carbon to strip out the caffeine. What is left is water fully loaded with pure flavor compounds. In the Swiss Water-Only Process this is called "flavor-charged water." It holds a saturated solution of the flavor compounds that belong in green coffee, with caffeine as the single exception, and this special water is the most important medium in the decaffeination step that follows.

When a new batch of green beans is soaked in flavor-charged water that is rich in flavor compounds but free of caffeine, the caffeine inside the beans is released while the flavor compounds are not. In this way the original flavor of the green beans is not significantly diminished. The logic is straightforward: the flavor compounds in the flavor-charged water are already close to saturation, so they cannot dissolve any more of the same, yet there is still plenty of room left to dissolve caffeine.

Once the green beans have been through this process, with the caffeine removed and the flavor preserved, they are dried and sold directly. The flavor-charged water that has absorbed the caffeine can be filtered through activated carbon again and again to clear the caffeine, then reused.

FrontStreet Coffee Recommendation

If you are watching your caffeine intake, the simplest rule is to skip Robusta and drink only Arabica, which generally carries less caffeine. Arabica needs altitudes from 800 to 2,200 meters where frost does not reach, and the greater day-night temperature swing at higher elevations slows the fruit's ripening, which helps the plant build up flavor compounds and develop a firmer aroma. Every growing region also has its own microclimate, giving Arabica a wide range of conditions and the distinctive regional flavors that come with them.

Among FrontStreet's Arabica single origins, the FrontStreet PWN Golden Mandheling is a rich place to start. Indonesia's wet-hulling method is a response to local conditions, but it is exactly what sets this Mandheling apart from other dark roasts, with the herbs, spice and wood notes that make it a classic. PWN applies three hand sortings on top of machine selection, removing defective beans as far as possible so that body and sweetness come through fully and the aroma stands out. It suits moka pot, single-origin espresso, pour-over, drip bags, americano and latte.

For a lighter, more aromatic cup, the FrontStreet natural Huakui carries a gentle floral tone with especially prominent fruit, including cream strawberry, mango, jackfruit, citrus and blueberry, the ripe tropical character typical of FrontStreet's Sidamo naturals. It took first place at the TOH green-bean competition on the strength of that berry-rich aroma and combines quality with a fair price. It suits pour-over, cold brew, moka pot and single-origin espresso. If you prefer a clean, bright cup, the FrontStreet washed Gotiti Cooperative is Ethiopia's top G1 grade, washed in the classic way and finished medium-light to show elegant white florals, citrus, orange and green tea, and it suits pour-over, drip bags and cold brew.