What is the Red Wine Processing Method in Coffee | Is Red Wine Added to Coffee with Red Wine Processing?

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Introduction to Red Wine Processing Method

When we talk about coffee processing, we usually think of washed, natural, honey, and wet-hulled methods. Today, FrontStreet Coffee would like to introduce the red wine processing method.

Coffee and red wine: have you ever considered the relationship between them? Traditional coffee processing techniques may be familiar to many, but how much do you know about coffee processed with red wine methods?

In 2015, World Barista Championship competitor Sasa introduced the world to a Colombian coffee bean processed in a way similar to red wine fermentation. Beyond the novel taste of the bean, the "red wine processing method" used to treat it sparked enormous curiosity among coffee lovers, ourselves included. So what exactly is this so-called red wine processing method?

Understanding the Red Wine Processing Method

Although the exact details of the red wine processing method remain largely unknown, we have combined the available information with our understanding of wine fermentation to roughly outline how this "red wine processing method" works.

The red wine processing method for coffee, also called wine-like processing, takes its inspiration from red wine fermentation. At present, only eight estates in Colombia have successfully brought coffee processed this way to market. Based on information from those eight estates, we can broadly divide red wine processing into three types: acetic acid fermentation, also called aerobic fermentation; lactic acid fermentation, also called anaerobic fermentation; and mixed fermentation, which combines aerobic and anaerobic.

Advantages of Red Wine Processing

Traditional processing methods struggle to control how far a coffee bean ferments. The red wine processing method can safeguard bean quality by controlling pH, and even temperature and humidity, while sealed fermentation keeps aromatic compounds from evaporating easily.

The Fermentation Process

Now let's look at the specific fermentation process. First, Colombian farmers carefully harvest the cherries and meticulously select red fruit, ensuring that among the cherries chosen for processing, unripe cherries make up less than 2%, defective beans less than 3%, and floaters less than 5%.

The selected cherries are then placed by the farmers in specific containers. When the Australian barista Sasa competed, the beans she used were processed in metal containers. Whatever the container type, it should be fitted with something like a red wine fermentation lock or a one-way exhaust valve. This lets carbon dioxide escape through the device, controlling the air concentration inside the container. At this point, the cherries in the container undergo acetic acid fermentation, yielding beans with relatively bright, clean flavors and a lemony acidity.

According to Sasa's description during the competition, processors inject carbon dioxide into the container to prevent oxidation from forming volatile acids. This process is lactic acid fermentation, which produces malic acid and tartaric acid. Because tartaric acid is relatively stable, beans produced through lactic acid fermentation have a mellow, rounder acidity, with cheese-like, nutty, and creamy flavors.

Characteristics of Different Fermentation Methods

Aerobic Fermentation = Acetic Acid Fermentation (AEROBIC)

Flavor characteristics: cleaner, bright and lively acidity, citric and citrus acids.

Anaerobic Fermentation = Lactic Acid Fermentation (ANAEROBIC)

Flavor characteristics: round, high body, relatively lower cleanliness, malic and tartaric acids.

Mixed Fermentation = (MIX FERMENTATION = AEROBIC + ANAEROBIC)

Flavor characteristics: full, medium body, smooth, fruit acids, amino acids, nuts, cream.

Summary of Green Coffee Processing Methods

All green coffee processing methods are designed to give consumers richer, more diverse coffee flavors.

They can be grouped into three main types:

1. Different substances involved in fermentation (skin, pulp, pectin, microorganisms)

2. Different fermentation environments (pH values, with or without water, with or without oxygen)

3. Different drying processes (natural sun drying, drying equipment, turning frequency, container materials)

By making use of natural elements such as sunlight, water, and wind together with the green beans themselves, more aromatic compounds are preserved in the coffee.

FrontStreet Coffee Recommendation

If the red wine processing method has sparked your curiosity about fermentation, FrontStreet's Colombia Sidra is a direct way to taste it. This Colombian bean is processed by anaerobic natural, a low-oxygen fermentation that converts more tropical fruit aroma into the bean. Roasted medium-light, it makes a complex, fragrant cup when brewed as pour-over, cold brew, a drip bag, or in a moka pot, with passion fruit, grape, apricot, and candied fruit notes.

For a more traditional Colombian profile, FrontStreet's washed Colombia Huila is a reliable choice. Medium-dark roasted, it brings out the sweet, nutty aroma of dark chocolate with a moderate body and oil, and it suits pour-over and French press as well as moka pot and espresso machine, so it works in an Americano or a latte. For those with a home espresso machine, FrontStreet's house specialty blend combines the creamy, nutty character of Brazilian coffee with the dark chocolate bittersweetness of Colombian coffee, pulling a fine golden crema that turns into a rich, smooth latte and is friendly to beginners.