So, with all the different processing of coffee greens invented in the last few decades, I don't even know how many different fermentation processes exist nowadays. Can someone enlighten me what are the different ways to ferment coffee cherries? More importantly, what the fermentation does to the final cup of coffee.

My short reading of online references tells me that there are aerobic, anaerobic, and mixed fermentation. In addition, some fermentation involves steps like carbonic maceration and inoculated fermentation with known strains of bacteria, yeasts, or fungi. Nonetheless, fermentation is a step in ALL coffee processing types whether they are washed, natural, wet-hulled, or honey-processed. Traditionally they are uncontrolled mostly aerobic, but modern processing techniques employed are aimed to tame the process under control for improved quality of the coffees. Poor, uncontrolled fermentation can lead to moldy or even chemical flavors in coffee, but when fermentation is successful, it can enhance a coffee's best attributes.

But do they really??? Do controlled fermentations produce "better" coffee? Has anyone tried the same lot of coffee side-by-side, one processed traditionally and one processed with a fancy name like "anaerobic natural fermentation, carbonic maceration" that adds substantial cost to the production? I have done a similar thing on the same lot of coffees for various degrees of honey processed (white, yellow, red, black) vs. washed, but not for the fermentation process. My conclusion from a small number of honey vs. washed processes was that they do produce "different" flavor profiles. But I could not say which is "better". Certainly, I did not find the honey-processed coffee to be sweeter automatically. The decision of which tasted better was all based on personal preference. One was not always better than the other.

Having a strong personal affinity for sake, miso, shoyu, and shio-koji, all products of Aspergillus oryzae (also known as kōji mold) Japanese: ニホンコウジカビ (日本麹黴) fermentation, I had to try this Koji-inoculated Columbia El Vergel Java Koji from Onyx. It was one of the most expensive coffees I have ever purchased in my life. Not knowing the peak for this coffee, when I received the box (10 oz roasted 7 days earlier), I opened and aliquoted the contents into a single dose portion. And placed them in individual Mylar bags and vacuum-sealed them. I had a cup on that day. And two weeks later I brewed another cup. Well, both cups tasted similar to my taste buds. No big enhancement or degradation by resting longer. Both were vibrant fruit-forward, with very sweet aromas, but with a very distinctive Koji smell that I associate with sake, miso, shoyu, and shio-koji, or in this case, especially Amazake*. It was unique, different, and interesting, but in the end, I did not like the coffee. It was not a cup I enjoyed for the reason that it did not taste like COFFEE at all.

The conundrum: Is a cup of coffee that tastes nothing like coffee a good cup of coffee?

*Amazake is a traditional non (or very low) alcoholic Japanese drink made of fermented rice with koji, which literally means "sweet" (甘) "sake" (酒)

Yeah, definitely there is an acquired taste aspect to any new coffee (or any drink or food) even though it is categorized as the same group. But again, NEW is not always equal to GOOD or BETTER. Call me a traditionalist. LOL

First off, all coffee is fermented, even washed coffees. The question comes down to how much and how well controlled it is. As soon as you pick the cherry, the skin is broken and various microbes start enjoying the sugars in the fruit.

The next thing is that all fermentation is anaerobic. This is part of the definition of the metabolic processes involved. The rest is marketing terms. One good reference is https://christopherferan.com/2022/08/19 ... processes/

Fermentation was originally used to soften the fruit so that it was easier to remove the seeds. In microbe-driven fermentation processes, organic compounds are produced as byproducts. Some of these are flavor precursors and contribute to the favor of the roasted and brewed coffee. Fermentation is an ongoing process that continues into the drying process. In some cases, there may be enough moisture in the stored greens for some fermentation to continue.

For most coffees produced, the ambient yeasts and bacteria are the fermenting agents. These are not the same as from the origin of the coffee plants. They seem to have been brought to the growing region independently, correlated with human activity such as colonization. The discussion about what is "appropriate" microbes is one that could be a thread on its own, as would co-fermentation.

Done well, through luck or intent, the duration of the fermentation and the microbes responsible add to the perceived quality of the brewed coffee. When things go wrong, the word "rot" is accurate. Coffee is only a few centuries behind in controlling fermentation compared to alcoholic beverages. It has only been a couple of decades that coffee processing (in general) has been valued by even a tiny fraction of the market.

Has anyone tried the same lot of coffee side-by-side, one processed traditionally and one processed with a fancy name like "anaerobic natural fermentation, carbonic maceration" that adds substantial cost to the production?

Yes, this is done regularly by roasters in their green selection process. A month or so ago, we cupped something like a dozen samples each from two different producers. There was a range from each of these producers from good to excellent. Even among traditional processing methods, the flavor profiles varied quite a bit. Based on the results, a buying decision was made and the order placed that day.

Jeff wrote:The next thing is that all fermentation is anaerobic. This is part of the definition of the metabolic processes involved. The rest is marketing terms.

If you define "fermentation" in a biochemical term, then you are correct. But I think the food industry and general public use the term "fermentation" in a much broader sense and defined as in the Wiki "any process in which the activity of microorganisms brings about a desirable change to a foodstuff or beverage" can be attributed to "fermentation". In that sense, there are some processes of "aerobic fermentation" that occur when microorganism activity is high in the presence of oxygen and mostly natural and uncontrolled in breaking down organic materials.

As I pointed out in my OP and as you mentioned, this type of uncontrolled fermentation occurs in ALL coffee processes mainly to break down mucilage and help pulp the coffee cherries. I am not asking about this type of fermentation. I am more interested in intentional and controlled fermentation introduced by the processor to improve the quality of the coffee in a cup, especially with the help of inoculants. Do they really result in a better cup?

And related question is does economy of the coffee production support such an invention? From a small sample I have seen, due to more labor and equipment required, they cost more than traditionally prepared coffees. Does the higher cost in those intentional and controlled fermentation processes always equate to better coffee?

The economics of the coffee production is a topic unto itself. In many ways and places, it hasn't evolved much from colonial exploitation and labor somewhere on the cheap, through indentured, to slave scale. In many places, even without "improved" growing, picking, processing, and storage, non-commodity coffee production is not economically viable.

Luca has had some choice words about how coffee is marketed at retail, much of which I agree with. When used simply as a marketing tool to boost revenue at retail, there isn't any positive value to the consumer.

One of the challenges is that there is a huge knowledge gap between most producers and the middlemen. Coffee production has been mainly an oral tradition. For generation after generation, the goal was commodity coffee, coffee whose primary sensory value is that it isn't bad. It was the roaster that was held in high esteem to be able to produce "coffee that tastes like coffee". It has only been in the last couple decades that this notion has been challenged in the speciality coffee niche. Because of this knowledge gap, middlemen would "helpfully" tell a producer or mill to do something that would "improve" their coffee, without transferring the knowledge of how to manage the process, either in a small batch or at scale. In some cases, producers were told to "do this" by a buyer and then left literally holding the bags when the buyer didn't like the result and didn't purchase what they had asked for.

Can controlled fermentation processes improve the in-cup result? Absolutely.

Naturals, ranging up through the various "honey" processes are luck/tradition/experience-based, extended, controlled fermentation processes. By how the producer manages the drying of the cherries the speed of and microbes responsible for the fermentation are managed.

Do controlled fermentation processes always improve the in-cup result? No. Like pickled vegetables, sourdough bread, or any other foodstuff that relies on fermentation for part of its flavor process, "rot" is a possible outcome.

Should the arcane rules around intentional selection of microbes and control of fermentation processes, including co-ferments be dropped? Absolutely. The current rules are asking producers to grow a non-native crop and process it with non-native microbes in some misguided, romantic concept of "terroir".

If you're a traditionalist and enjoy the more traditional profiles, don't worry, there's lots of conventionally processed coffee out there in the roughly 10 billion pounds produced annually.

jpender wrote:I know your question has to do with how to categorize new things in an ever changing world. I can't really help you with that except to say that change is going to keep happening, probably at a faster rate than you'd like.

Yeah, I like experimenting. But when it comes to a cup of coffee, I am a traditionalist. The world around me may be changing, but that does not mean I have to change along.

jpender wrote:But with regards to amazake, it's my understanding that it is not a fermented product, at least not necessarily. Rather, amazake includes an ingredient (Koji rice) that has been fermented with a particular fungus. The amylases produced by that fungus are present in the Koji and serve to break down the starches in the cooked rice it is added to. You end up with a very sweet unfiltered syrup.

This again depends largely on how you define "fermentation". Sure, the method you have described using Koji rice for Amazake-making does not require lengthy periods of development for the alcohol fermentation to take place. But the fact it requires koji-rice (rice that has been inoculated with Aspergillus oryzae) means rice has been fermented. By the way, there is another way to make Amazake, which is to use sake-lees or Sake kasu (酒粕) which is a pressed leftover of sake production, and mix it with sugar and water. Again, it does not undergo lengthy development, but the sake lees have already been fermented for a period of time. Either way, the term Fermented Japanese Rice Drink applies to the beverage.

Jeff wrote:For generation after generation, the goal was commodity coffee, coffee whose primary sensory value is that it isn't bad. It was the roaster that was held in high esteem to be able to produce "coffee that tastes like coffee". It has only been in the last couple decades that this notion has been challenged in the speciality coffee niche.
-snip-
If you're a traditionalist and enjoy the more traditional profiles, don't worry, there's lots of conventionally processed coffee out there in the roughly 10 billion pounds produced annually.

One impression I have been getting ever since I joined the forum a few months ago is that there seems to be so much emphasis on fruit-forward, light-roast coffee among many here. Does it have to be fruity and light to be called specialty coffee? Is that part of the definition of specialty coffee? I swear, for the past few decades I thought I was roasting specialty coffee greens and many of them had traditional coffee profiles.

Jeff wrote: Should the arcane rules around intentional selection of microbes and control of fermentation processes, including co-ferments be dropped? Absolutely. The current rules are asking producers to grow a non-native crop and process it with non-native microbes in some misguided, romantic concept of "terroir".

Sorry, but I don't understand what you are getting here. What rules are you talking about? Is there any enforcing agent who monitors what microbes can be added to the coffee fermentation process?