What is the Red Wine Processing Method for Panama Hartmann Coffee? What is Coffee Anaerobic Fermentation?

What the "Wine Process" Actually Means

The wine process has become one of the most talked-about methods in coffee. During the journey from coffee cherry to green bean, fermentation happens to some degree no matter what you do—washed, honey, or natural, they all pass through it. What differs is which substances take part (fruit skin, pulp, pectin, the types and distribution of microbes), the fermentation environment (with or without water, aerobic or anaerobic, the pH), and the drying method (container material, sun-drying, mechanical drying, how often the beans are turned). Change any of these and you change the flavor and mouthfeel in the cup.

Wine Processing, a.k.a. Carbon Dioxide Maceration

Also called wine-like processing, this method borrows directly from winemaking. To date, only eight estates in Colombia have successfully brought wine-processed coffee beans to market. Based on what those eight estates have shared, wine processing can be grouped into acetic acid fermentation (aerobic), lactic acid fermentation (anaerobic), and mixed fermentation (aerobic plus anaerobic).

Traditional processing makes fermentation hard to control. Wine processing controls it by managing pH—and even temperature and humidity—while sealed fermentation keeps the aromatic compounds from escaping.

Carbon dioxide maceration is a newer technique within wine processing: whole grapes are placed in a carbon dioxide atmosphere to create an anaerobic state, so that even without added yeast the fruit converts its own sugar into alcohol and develops special aromas. Wine made this way is softly aromatic, full in the mouth, and stable in color.

The moment carbon dioxide maceration first came to the coffee world's attention was 2015, when Sasa Sestic won the World Barista Championship using a washed bean processed by carbon dioxide maceration.

How Is It Different from Natural, Washed, and Honey?

Natural, washed, and honey processing all rely on fermentation too, but they work with the fruit in the open. Maceration takes the coffee into a sealed, oxygen-free vessel and hands the processor real control over temperature, time, pH, and the gas environment—so the results become far more repeatable.

How It Is Applied to Coffee

1) After the pulp and skin are removed, the beans go into stainless steel containers. Why stainless steel? Sasa says it does the best job of keeping the flavor clean. Temperature is then varied to change how fast the reaction runs.

2) The containers are kept indoors, where temperature is easier to control. The team found that if you want more complex acidity in the bean, hold the temperature at 4-8°C; if you want more sweetness, hold it at 18-20°C.

3) The fermentation tank is sealed, which allows more aromatic compounds to develop.

4) This is the crucial step: carbon dioxide is added to the tank. Carbon dioxide is denser than oxygen, so it pushes the air out and puts the beans in an anaerobic environment. With no oxygen present, the breakdown of sugar in the bean's pectin slows down, and the pH falls more gradually as well.

With the help of carbon dioxide, the entire fermentation at 22°C is extended by 3 days, and at lower temperatures it can run even longer. This reduces astringency and acetic tones. Throughout the process, every reading—pH, fermentation temperature, and the amount of carbon dioxide—is recorded, so the results can be corrected and repeated later.

FrontStreet Coffee's Panama Hartmann

FrontStreet Coffee's Panama Hartmann is processed this way. The wine process gives the bean a rich, fermented wine aroma that genuinely surprises you.

FrontStreet Coffee Pour-Over Parameters

V60 / 90°C / 1:15 / about two minutes.

Flavor: grapefruit, low acidity, rich fermented wine aroma.

FrontStreet Coffee Recommendation

If the idea of controlled fermentation is what caught your attention, the most direct way to taste it is a bean built entirely around anaerobic fermentation. FrontStreet's Colombia La Divisoria Sidra is anaerobically natural-processed: after the oxygen-free ferment the coffee develops far more tropical-fruit aroma, and at a medium-light roast it delivers a layered, perfumed cup of passion fruit, grape, apricot, and dried fruit with real juice-like body. It shines as pour-over, cold brew, drip bag, or moka pot.

For something rounder and more everyday, look at FrontStreet's washed Huila, also from Colombia. Medium-dark roasted, it leans into dark chocolate and nutty sweetness with a moderate oiliness and a full body—easy in a pour-over or French press, and equally happy as moka-pot or espresso-machine coffee for an americano or latte. Either way, you get to taste the same principle the Hartmann is famous for: when you control fermentation, you control flavor.