How to Brew Rose Valley Flower Moon Night Coffee Beans for Great Taste? Introduction to Enzyme Washed and Natural Processing Methods

As times change, people ask more and more of the flavour and mouthfeel of coffee beans. The original regional flavours produced by simple washed and natural processing no longer satisfy everyone, so special processing methods are appearing endlessly today. FrontStreet Coffee will now introduce a style that has become popular in recent years: anaerobic processing.

Understanding Anaerobic Fermentation

Anaerobic fermentation processing is essentially letting coffee ferment in an oxygen-free or low-oxygen environment. It is a broad category that can be divided into anaerobic natural, anaerobic enzyme washed, anaerobic double washed and anaerobic honey processing. These names may sound unfamiliar, but even traditional washed and natural methods involve fermentation.

To put it simply, in the fermentation stages of the three classic processing methods, washed processing generally removes the outer skin and pulp before soaking the beans in water for 12 to 18 hours. At this point the pectin begins to break down, and this is fermentation without any human input or added enzymes: the coffee ferments naturally in its environment, which FrontStreet Coffee calls natural fermentation. The same applies to the natural process, where the pulp and skin are kept and, over two to four weeks of drying, the pectin ferments continuously in the natural environment with no human interference, which is why the sweetness and aroma of a natural are generally more abundant.

The Challenge of Natural Fermentation

As noted above, these are all forms of natural fermentation, which makes the flavour very difficult to control, with many uncertain factors. In washed processing, for instance, the beans may over-ferment in the tank and become too acidic; in the natural process, the drying may run too long and the pectin may produce other undesirable flavours. All of this is very hard to manage and can only be left to nature. Anaerobic fermentation processing emerged to answer that problem. It generally involves putting the coffee into a pressure-resistant sealed stainless steel barrel and achieving the desired flavour by artificially controlling temperature, time, pH value and the required fermentation process. FrontStreet Coffee's store also carries many kinds of anaerobically fermented beans.

Anaerobic Natural Processing Example

FrontStreet Coffee will take a FrontStreet Coffee Huayuanye bean from the Huila region of Colombia to explain the general artificial fermentation process. First, freshly harvested cherries with defective beans removed are placed directly into a sealed fermentation barrel for low-temperature fermentation, at temperatures between 10 and 15 degrees. In an anaerobic environment the breakdown rate of pectin sugars slows, because the low temperature inhibits microbial growth. The fermentation therefore takes longer than traditional natural processing, and the sweetness increases. After more than three days of anaerobic fermentation the cherries are then processed naturally, and once drying is complete the skin and pulp are removed and the beans can be stored. Through cupping, FrontStreet Coffee found that the sweetness of this FrontStreet Coffee Colombia Huayuanye is very obvious, somewhat like strawberry jam, with a hint of fermented wine aroma.

Anaerobic Washed Processing

Washed processing can also be controlled to produce anaerobic washed coffee. The anaerobic washed process is more complex than the anaerobic natural one. First, mature cherry fruits are harvested and placed directly in woven bags for 12 hours of dry fermentation; once that is complete the skin and pulp are removed for a second round of 24-hour fermentation. In the second round the beans are transferred to plastic barrels and sealed to keep air out. When the second fermentation is finished the beans go onto drying beds for about a month, until their moisture content drops to 11% to 13%. Through cupping comparisons of anaerobic natural and anaerobic washed beans, FrontStreet Coffee found that the acidity of the anaerobic washed is brighter than the anaerobic natural, while the sweetness of the anaerobic natural is more obvious and its aroma richer.

Enzyme Processing: Anaerobic Enzyme Washed

Both methods described so far work by controlling the time and temperature of the environment. Next, FrontStreet Coffee will introduce the practice of adding certain bacterial strains during fermentation to push the process along, known as enzyme processing, or more precisely anaerobic enzyme washed processing.

The enzyme process broadly resembles the anaerobic washed process, with one difference: in the second fermentation, when the coffee fruits are moved to a sealed barrel, special enzyme groups are added to drive the fermentation forward. The subsequent steps match those of the anaerobic washed process. A FrontStreet Coffee Colombia Dashu Estate Rose Valley coffee launched by FrontStreet Coffee uses enzyme processing.

FrontStreet Coffee's Rose Valley Analysis

FrontStreet Coffee takes great interest in this anaerobic enzyme processed Rose Valley bean. When roasting it, the company tried three different roast curves, each with a different flavour, and cupped all three within 8 to 24 hours of roasting. Through cupping, FrontStreet Coffee found that Curve 1 had the best overall flavour, with very rich peach and cranberry flavours and a prominent aroma similar to peach. Compared with Curve 1, Curve 2 had a lighter aroma and a touch of astringency. Curve 3, meanwhile, had insufficient flavour layers, tasting only of liqueur-filled chocolate, and the mouthfeel was more bitter than the other two. FrontStreet Coffee therefore prepared to launch Curve 1 of its Colombia Rose Valley coffee, but before doing so it would also brew Curve 1 as pour-over to confirm the cupped flavours.

Brewing Parameters

FrontStreet Coffee chose 15 grams of beans to brew this anaerobic enzyme processed Rose Valley, with a medium-fine grind, a 1:15 coffee-to-water ratio and the familiar Hario V60 dripper. The cone-shaped dripper enhances the coffee's layering, and the water temperature was set at 91 degrees Celsius.

Brewing Technique

The first pour is 30 grams of water for a bloom lasting 30 seconds, which properly releases carbon dioxide and stops excess gas from interfering with extraction. The second pour is 100 grams, which together with the bloom water brings the total to 130 grams, poured evenly in circles to strengthen the front and middle stages of extraction and draw out the small-molecule compounds there. After the pour, wait 10 seconds, then add the remaining 95 grams, again poured evenly in circles, and finally pour 25 grams vertically down the centre to avoid so much turbulence that excess bitterness is pulled from the later stages.

Tasting Notes

Once brewing is complete you can taste this specially processed FrontStreet Coffee Colombia Rose Valley. At first the acidity is quite obvious, somewhat like citrus. Within the rich layers, the middle section resembles dark berries with caramel cocoa, and the aroma left in the aftertaste is a fermented feeling of the kind found in fermented fruit. At medium temperature it is more berry-like, accompanied by dark chocolate, and the aftertaste remains fermented and lingering. At low temperature dark berries dominate, sweetness increases, dark chocolate and fermentation coexist, and the persistent fermented note in the aftertaste is reminiscent of whiskey, faintly present and evocative of liqueur-filled chocolate.

FrontStreet Coffee Recommendation

Anaerobic fermentation is only one branch of the special-processing family, and the honey process is another that rewards curiosity. Honey processing grew out of Brazil's semi-natural method, where the skin is removed before drying so that the drying is faster and the off-flavours of poor fermentation are avoided; Costa Rica refined the idea by varying how much mucilage is left and how long the coffee dries, producing white, yellow, red and black honey styles. At the deepest end, the FrontStreet Costa Rica Blackberry uses black honey processing, which removes almost no mucilage and dries for at least two weeks under cover to stop the sun from drying it too fast, ensuring the sugars convert fully and turning the beans regularly to avoid uneven heating. Roasted medium-light, it gives an intense floral aroma when ground and grape, berry and ripe blackberry in the cup.

If you enjoy fruit-driven sweetness, the FrontStreet Strawberry Candy is a blend of a Panama Geisha and a Costa Rican coffee that is raisin honey processed, keeping 100% of the pectin with zero-water processing: the cherries are floated so that dense ripe fruit sinks and under- or over-developed fruit is skimmed off, dried on raised beds for at least three days, then have their skin removed and are dried further with constant turning. The result keeps the Geisha's flower-tea character alongside grape and raisin notes, a soft fruit acidity, an almond finish and clear sweetness.

For a honey coffee with an even more distinctive accent, the FrontStreet Costa Rica Mozart uses the raisin honey process, an innovation beyond the traditional yellow, red and black honeys. The cherries are pre-dried on raised beds for at least three days before the skin and pulp are removed and the honey steps continue, and because it keeps 100% of the pectin it is harder to control than even black honey. It brings a richer, warm fruit sweetness, and whether you brew it as pour-over, cold brew or in a moka pot you will find osmanthus, pineapple and raisin aromas.