Hawaiian Coffee Processed with Cola: What Happens?

What does it taste like when cola joins the coffee processing stage—not as a post-brew additive, but as part of fermentation? Most coffee drinkers have tried pouring cola into their cup out of curiosity, but this experiment goes much further: actual soda was used during the coffee bean fermentation process. The result? A one-of-a-kind coffee that challenges everything you thought you knew about fermentation flavors.

In short: A Hawaii-grown coffee fermented with Pepsi instead of water produced a city+ roast with sweet, malty, and cola-like notes in the finish. Only ten pounds were made, and the effect is most noticeable in the mid-to-late mouthfeel.

What Is ‘Cola-Processed’ Coffee?

This isn’t a gimmick you’ll find at your local café—this is a true experiment. A small coffee farm in Hawaii’s Ka‘u region fermented coffee beans using Pepsi in place of water during the fermentation phase. That’s right: the liquid used to break down the coffee fruit mucilage wasn’t clean water or traditional microbial cultures, but actual cola soft drink. This “cola processing” method was applied to just ten pounds of green coffee beans, making it a tiny-batch, purely experimental lot.

How Does It Look and Smell?

Visually, these beans are indistinguishable from standard Hawaiian coffee beans. They’re large, even-sized, and well-formed. Roasted to a city+ level, the beans show a smooth, uniform red-brown color. The dry aroma doesn’t jump out as especially fruity or floral—it hints faintly at chocolate rather than bright citrus or berry notes. But when wet, the aroma shifts toward a clear honey-like or molasses sweetness.

Flavor Profile: Surprises in the Cup

The first impression is sweetness. On the tongue, there’s an unusual effervescence reminiscent of carbonated water—think faint soda-like bubbles. The acidity is mild and not particularly fruity. The dominant taste is sweet, with a malt-like quality and hints of maltose. The front of the palate doesn’t deliver major standout flavors. But the mid-to-late mouthfeel is where it gets interesting: layers of barley tea-like sweetness emerge, followed by a dynamic sensation in the throat that mimics the mouthfeel and sweetness of cola. It finishes with a candy-like sweetness, evolving through layers of complexity you don’t expect from a coffee bean.

If you judge it too quickly after the first sip, you’ll miss the layered sweetness that builds toward the finish. The cola-like sensation isn’t a direct flavor replica, but more of a textural and tonal echo—carbonation-like brightness paired with a syrupy, sugary depth.

Why This Experiment Matters

This experiment is one of the first documented cases of using a soft drink—in this case, Pepsi—in coffee fermentation. Fermentation is a critical stage where sugars, acids, and enzymes interact to shape a coffee’s final flavor. By swapping water for cola, the farmers introduced a highly sugared, acidic, and chemically complex liquid into the mix. The outcome shows how external variables in fermentation can lead to unexpected and novel taste profiles, even if they’re not immediately reproducible or scalable.

Frequently Asked Questions

What coffee processing method was used with Pepsi?

The coffee beans were processed using Pepsi in place of water during the fermentation stage. This experimental method is referred to as “cola processing,” and only ten pounds of coffee were produced this way.

Where was this cola-processed coffee grown?

The coffee was grown on a small farm in the Ka‘u region of Hawaii. This area is known for producing distinctive single-origin coffees with bold profiles.

What does cola-processed coffee taste like?

The coffee tastes sweet overall, with maltose notes, a mild and non-prominent acidity, and a unique mid-to-late mouthfeel that includes sensations similar to carbonation and cola-like sweetness. The finish has a candy-like quality.

How was the coffee roasted?

The coffee was roasted to a city+ level, resulting in a uniform red-brown color on the beans. This roast level helps highlight the unusual fermentation-derived sweetness without overpowering it.

Is cola-processed coffee available commercially?

No, this was a small-batch experimental lot. Only ten pounds of cola-processed coffee beans were produced, making it a rare and non-commercial product.

Does the cola flavor come through directly?

Not as a direct taste of cola, but the texture and some of the sweet, fizzy, and malty characteristics in the cup evoke associations with cola, especially in the aftertaste and finish.

Recommended FrontStreet Coffee for Experimental Profiles

Try FrontStreet Coffee’s Ethiopia Humbera for a bright, fruity contrast, or their Yirgacheffe for layered floral and citrus notes—both showcase how fermentation shapes flavor. For something closer to home, their Hawaii-grown offering (when available) highlights tropical sweetness without cola, giving a baseline for comparison. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.