Sharing the Risks & Rewards of Innovation

"I think it’s really important that roasters and processors have a better understanding of the risks so that we can share them and help make our supply chain more equitable,” Tim says.  In this article, Tim dives deep into yeast inoculated processing as we seek to understand what it might mean for specialty coffee and what roasters and importers can do to help processors succeed.

Tim, you’ve been in coffee for a long time and have been an advocate for calling this “yeast inoculated process.” Why is that the most accurate way to describe this type of coffee processing?

Tim Heinze: The term “yeast inoculation” helps define and accurately describe the unique way in which specific yeasts are added. The operative term is “inoculation” because, technically, ALL processing methods could be called “yeast processed” since they involve some level of yeast interactions during processing. The one exception is mechanically demucilaged coffees when they are processed immediately after harvesting.

Why do you call it a “strategy” and not a “processing method”?

TH: I think it’s even more accurate to describe yeast inoculation as a “strategy” rather than a “process” since it can be utilized in combination with any other processing methods to impact flavor and/or create consistency across batches. I realize that in some areas (like the label on a roasted coffee bag), the need for brevity might not allow for this, but I believe it’s vital to use accurate and descriptive terms to enable us to share knowledge across our industry.

Now that we have our terms down, what’s happening during yeast inoculation? 

TH: In traditional washed processing, the processor relies on microbes to break down the pectin enzymes that bind mucilage to the parchment and contribute flavor characteristics to the final cup.The difference in the yeast inoculation strategy is that the processor is attempting to control which microorganisms are active during the fermentation that takes place between harvest and the start of drying.

We do know that different microbes produce different by-products depending on the environment they’re in. By attempting to control the environment and which microbes are present, the processor is seeking to control the final quality result as well as consistency between batches.

Why are processors choosing to use yeast inoculation?

TH: First, many producers believe yeast inoculation is one way to tap into a market that rewards differentiation.

Second, I think coffee processors are looking at yeast inoculation to increase consistency across batches. Most processors are receiving fresh coffee for anywhere from 45 to 90+ days during the harvest. They’re going to process these as smaller lots and then combine them later, usually at the dry mill. For processors, there are so many factors – temperature, humidity, the coffee itself – that make it very difficult to maintain consistency across batches, so yeast inoculation is one potential way to create a more consistent product.

Third, yeast inoculation has the potential to give processors greater control over the flavor and quality of their final product. I’ve found that people pursuing this strategy believe that yeast inoculation will allow them to impact flavor development more directly and with greater control than in typical washed processing.

Finally, yeast inoculation can make biological mucilage removal easier in regions where it is typically challenging, such as high altitudes where cooler temperatures slow or prevent this.

However, when it comes to potential impact, there just isn’t enough evidence concerning the details of how wild and inoculated microbial communities interact during processing. The diversity that exists in non-inoculated fermentation might be exactly what makes a producer’s coffee unique, OR it might be a contributor to keeping them from achieving consistent quality in the cup. Some locations and processors saw their quality decline when they used inoculation. Others felt it improved their quality. 

What does that mean for processors?

TH: Since there are still so many uncertainties, it’s likely that different processors experimenting with different yeast strains are getting different results.

TH: Here are two things to keep in mind if you’re a roaster asking a producer to try yeast inoculation:

One: There’s a big difference between trials and large-scale lots. The results of a sample batch placed in a bucket one year is not a good indication of what the results of bags or tanks worth of coffee processed in exactly the same way will be like. While essential for both a processor's income and a roaster-partner's success, scaling up isn’t a 1-to-1 process, and even the same exact process can lead to vastly different results.

Two: Producers are carrying a lot of risk with this strategy. When cup quality isn’t as expected, producers frequently struggle to find buyers. If you are working with a producer who’s experimenting with yeast inoculation, working together to create a path forward and committing to buy the coffee regardless of the result is crucial.

What are the difficulties of this method?

TH: Financing is frequently a problem for smaller producers. Even though the inoculants are the only requirement, they can represent a significant expense for those who are not making significant profits on their coffees. Additionally, many smallholders are typically located in remote areas where it can be logistically difficult to receive the inoculants.

Another barrier is access to information and training. Rehydrating yeasts is not too difficult, but it does require training. This means that producers without access to training or ways to obtain information – such as easy internet or phone access – can be excluded from yeast inoculation.

All that being said, it’s still not a given that yeast inoculation will help producers access new markets and make more money. The complexity of the chemistry and microbiology behind processing means that we need for more research and information before we consider yeast inoculation a viable, large-scale strategy for increasing producer incomes.

So, what’s next for yeast inoculation?

TH: I think that’s where our role as the importer comes in. It’s important to remember that yeast inoculated processing is one potential route to increased income for farmers. It’s a strategy, not a panacea and no one solution is going to work everywhere and for everyone.

I think we need innovation, and we need to communicate about sharing risks. As importers who span the supply chain, we’re perfectly positioned to help support processors and roasters navigate these evolving techniques.