How to Find Your Perfect Cup of Coffee: A Comprehensive Guide to Understanding Coffee From Farm to Cup
Part 2. “Wet” vs. “Dry” Coffee Bean Processing
In Part 1 of this series we explored the difference between Arabica and Robusta coffee plants on our quest to understand what effects the final flavor of a cup of coffee. Now that we understand the difference between the two plants and their different attributes, it’s time to follow the coffee cherry off the plant.
Coffee, the drink that the wakes a majority of the world up every morning comes from a bean that grows inside of a fruit or “cherry”. This fact is hard to ignore with roasters boasting increased fruity flavors or the innumerable artsy photographs of coffee plants that plaster the walls of coffee shops all over the globe. Yet despite knowing the bean’s origin, a majority of coffee drinkers have no idea how coffee goes from a cherry on a plant to the beans on your kitchen counter or the drink in your cup. Even fewer understand how differences in this transformative process influence not only the flavor of your cup but also the amount of caffeine that your morning Joe holds.
(To learn about the different between the two most common coffee plant species check out our last post)
So what in the world does “wet” vs. “dry” processing mean? Isn’t all coffee wet?
The terms “wet” and “dry” refer to the way the beans are fermented and dried before they are roasted — a process that seriously impacts things like flavor, acidity, and caffeine content.
THE WET METHOD
After the cherries have been harvested from the plants and the unripe or lower quality fruits have been removed, they are sent through a “depulper” that… you guessed it, completely removes the fruit of the coffee cherry (or the pulp) from the bean.
The beans must be depulped as soon as possible after harvesting (usually less than 24 hours) before the fruit begins drying. After the bean has been removed from the fruit, the fruit is washed away and the beans are left with only a thin membrane of sugar and alcohols called the mucilage.
The beans and their mucilage coatings are allowed to ferment for 12–36 hours with bacteria and microbes. While the beans ferments, the sugars and flavors from the mucilage are absorbed into the bean, so that when the beans are washed again, only the dried mucilage and the enzymes are taken away.
Now that the beans are squeaky clean and only coated in their parchment-thin skin, they are dried.
In Santa Fe, producers like to take advantage of the powerful Panamanian sunshine and dry their beans are on screens and pallets. While drying beans sounds simple, the process actually requires a significant level of expertise. If the beans become too dry then they will lose flavor and some of their quality. If the beans are not dried enough however, the beans will rot in storage.
The beans are routinely turned in order to ensure they dry evenly and the coffee is ordinarily kept under carefully maintained shade in order to ensure perfect drying temperatures. While the desired moisture percentage changes depending on where the coffee is produced, in Santa Fe, Panama, the local coffee producers aim for 11–12% moisture.
THE DRY METHOD
The “dry” method of coffee processing is also called the “natural” or “traditional” way of processing coffee. In this method, the coffee is picked and immediately dried WITH the cherry intact.
After being harvested, the cherries are immediately laid out on drying racks in the sun. Similar to the beans at the end of the “wet” process, the coffee is routinely raked and turned so that the cherries dry evenly. The coffee is also highly regulated to ensure the perfect level of drying.
There are some common misconceptions in the coffee industry that wet process leads to higher quality beans and better tasting coffee. This rumor, likely created by the marketing team of a wet process brand, should be thoroughly disregarded.
Because the bean is being dried WITH the cherry and its mucilage, the bean has the opportunity to not only absorb the fermenting sugars and the alcohols from the mucilage but also the additional sugars and flavors from the cherry.
It takes the “dry” process cherries about four weeks to fully dry before they are ready to have the dried fruit removed.
Once the beans are dried and ready to be roasted it is nearly impossible to tell them apart, so what is different when those two beans hit our morning coffee cup?
TASTING NOTES
I first want to clarify that while I talk about coffee flavors there are an infinite number of combinations and variables that can influence the taste of a cup of coffee. So before you put all your chips in on one processing method, make sure you know the what the species of coffee being used tastes like and if you like the way that a certain producer’s coffee tastes.
The “wet” process produces coffee that is generally brighter, fruiter, cleaner and more acidic.
Coffee from the “dry” process is described as heavy in body, sweet, smooth, rustic and complex.
To simplify: wet =softer and dry = stronger. For caffeine junkies, I will also point out that because the coffee is dried along with its cherry in the “dry” process, the bean is able to absorb the additional caffeine from the fruit. Meaning that the caffeine winner for Part 2 is….”dry” process coffee!!!
To see the steps of the “wet” and “dry” processing yourself, stop by the Coffee Mountain Inn and take our Coffee Tour, which allows you to witness (and taste!) the coffee process form plant to coffee cup!
If you want to learn what comes next in the coffee bean’s journey to your cup, check out Part 3!