Extraction Theory, and You!

“Extraction is a measure of the solubles yield. It is also expressed as a percentage, comparing the amount of coffee flavoring material in the beverage to the amount of coffee grounds used to prepare the beverage. Approximately 28% of the organic and inorganic matter matter contained in roasted coffee beans will readily dissolve in water. The remaining 72% is cellulose bean fiber that isn’t water soluble under normal brewing conditions.”

— Ted Lingle, The Coffee Brewing Handbook, 2011 Specialty Coffee Association of America.

When we talk about extraction, we are evaluating the process in which particles dissolve from the ground coffee into the water. Roasted coffee is a wonderfully complex thing. Though only 28% of every coffee bean can dissolve in water, that 28% represents 800-1000 different flavor compounds, half of them aromatic gasses, and half of them soluble solids. It’s much, much harder to track what gasses we’ve pulled from the ground coffee into the brewed coffee, so we’re usually more concerned about the coffee solids we’ve dissolved: what are they, and how much of them have we dissolved?

It’s pretty easy to break up the soluble material in coffee into four basic categories: fruit acids, which come from the fruit itself; fruit sugars, which are also derived from the coffee fruit; caramelized sugars, which develop during the roasting process; and bitter, dry plant solids. Acids dissolve pretty easily, sugars take longer to dissolve, and those bitter, dry plant solids are pretty dense and are made up of large molecules that take the longest to dissolve. Because these all dissolve in the same order, when we calculate an extraction yield as 15%, 21%, or 25% of the total soluble material, we can usually assume a certain concentration of those four main categories of coffee solids. From 0-18%, we’re seeing the fruit acids dissolving in high concentrations. From 18-22%, the fruit sugars and caramelized sugars start dissolving in higher concentrations, and from 22% to 28%, we see the dry, bitter plant solids dissolving in higher concentrations. Therefore, ideally, we’d like coffee extraction yield readings to land around 19-21% for the sweetest brewed expression of what that coffee has to offer.

The extraction yield is just an average though — anytime you’re brewing coffee, the smaller particles will dissolve quicker, and the larger particles will dissolve slower. So in a 19% extraction yield, we’re assuming the larger particles might only be extracted to 17%, while the smaller particles maybe would have extraction to 21%. The more consistently even your grind setting, the more consistent your extraction yield will be. This is the main crux for the importance of not only just using a burr grinder, but a quality, precision burr grinder.

The reason for this disparate extraction yield has to do with how the coffee actually extracts. There are three main phases: Wetting, in which the coffee particles absorb water and push the remaining gasses out; Extraction, in which the solubles inside the particles actually begin dissolve into the water and start exiting the coffee particle into the overall solution; and Hydrolysis, in which larger insoluble carbohydrates are broken down into soluble ones. With smaller coffee particles, the water can penetrate and dissolve the solubles very quickly. Larger coffee particles require the water to penetrate deeper, and have more solubles to extract, so it takes longer inside the particle to dissolve the desired solids before the brew leaves the particle to join the overall brewed coffee solution. 

It’s because of this relationship between brew time and particle size that we are able to control our coffee brewing process more specifically. When paired with an appropriate ratio of coffee to water, a brew temperature around 200ºF, and controlled agitation, extracting the positive flavor solids and leaving the negative ones behind becomes an easy solution. (Please forgive the pun).

Simran Sethi’s love letter to coffee


Simran Sethi is a sustainability celebrity.  She has appeared on Ellen, Martha Stewart and Oprah as a sustainability expert and lectured on environmental issues in classrooms and conferences all over the planet.  The Independent of London named her an “eco-hero,” Vanity Fair called her “The Messenger” in its Green Issue, and her agenda for environmental change was considered by the editors of Variety as worthy of publication as those of Julia Louis-Dreyfus, Sheryl Crow and Laurie David, among others.

She is a gifted communicator and award-winning journalist who has reported on environmental issues for MTV, NBC, PBS and others.

She is an unrepentant activist who communicates around sustainability issues with the explicit intent of moving readers, viewers and listeners to action.

And she is the author of Bread, Wine, Chocolate: The Slow Loss of Foods We Love, which was named one of the best food books of 2016 by Smithsonian Magazine.  The book is about the decline of agrobiodiversity in our food systems — hardly the sexy stuff of talk shows and glossy magazines.  And it is exhaustively researched and thoroughly footnoted — attributes we generally do not associate with readability, relevance or commercial success.  But this book is all three of those because it applies a lesson Simran learned the hard way over many years as a journalist.

In order to give her reporting on environmental issues the credibility she felt it needed to move people to act, she crammed it with ecological and economic data.  She even earned an MBA to make the business case for sustainability more effectively.  And all that effort failed to move the needle.  Why?  “We were doing it wrong,” she says.

Psychologists and behavioral economists, Simran says, have shown that people have a “finite pool of worry” — we can only care deeply about a limited number of things.  As a journalist, she used data and analysis to try to expand their finite pools of worry to include the issues that were important to her, but it didn’t work.  So with BWC, Simran takes another tack, instead attaching the complex and urgent issue of agrobiodiversity to things already in people’s narrow frames of reference.  Things we may be able to live without, but things without which life would be a little less worth living: bread, wine, chocolate, beer and, yes, coffee.  (Even though coffee doesn’t make the title, it occupies an entire section of Simran’s book, a sacred space in her morning routine and a privileged place in her finite pool of worry about the future of the planet.)

This time, she doesn’t do it wrong.  The book succeeds in bringing issues of agrobiodiversity to a broader audience because it is first and foremost the intimate travelogue of a food pilgrim who visits the places where her favorite foods are produced and celebrates the people who make them delicious.  (More than a few readers have called it Eat, Pray, Love for food.)  It is only secondarily an urgent and convincing warning that those foods are endangered by the accelerated narrowing of the genetic base on which they rest.

In the latest episode of the Intelli Sourcing Sessions, we talk with Simran about the book and about coffee — what it means to the cultures and ecologies of the countries where it is grown and the societies where it is consumed, what its loss might mean for all of us, whether it is most like wine, beer or chocolate, and how we can communicate around coffee to make more people care more about it.

You can listen to our conversation with Simran Sethi here.

Read an excerpt of the coffee section of her book Bread, Wine, Chocolate here.

For more from Simran, check out The Slow Melt, her new podcast about chocolate.  The first episode doesn’t air on Kansas Public Radio on January 27, but you can subscribe now.

And if you haven’t subscribed yet to the Intelli Sourcing Sessions podcast, do it now on iTunes or Soundcloud so you don’t miss more conversations like this one.

 

 

Rwanda: Begin at the beginning

I sat down recently with my colleague Geoff Watts in our makeshift studio here in Chicago to record introductions of our two current Rwanda offerings: the single-farm Gaspard lot and the Zirikana lot from Buf Coffee’s Nyarusiza washing station.  Geoff is nothing if not thorough in his communications, and he began the conversation, as he tends to do, at the beginning.  We soon realized that before we tell the stories behind our current crop Rwanda coffees, we need to tell the story of the Rwanda itself, and how a country that didn’t have a specialty coffee sector 20 years ago has come to be such a reliable source of such delicious coffees.

In telling that story, we lean heavily on Geoff.  After all, he was present at the creation, and he did make some mighty contributions to the process over a period of many years.

We also reach out to the guy who started it all, Tim Schilling.  Coffee people of a certain generation may know Tim only as the CEO of World Coffee Research.  What they may not know is that Tim got his start in coffee in Rwanda, leading a project called PEARL that has become a reference point for every other coffee project ever implemented since — a benchmark, an aspiration, an inspiration.  But PEARL wasn’t designed to be a coffee project at all.

When Tim, a Mississippi-born peanut breeder, took the reins of the project, he had never worked in coffee and didn’t plan to start in Rwanda.  His task was simply to devise and implement a rural development project that would benefit as many people in Rwanda’s countryside as possible.  When he and his team fanned out in the field to identify crops with potential to deliver on the project’s mandate, one word echoed louder than all the rest that rose from the country’s thousand hills: coffee.

The Rwanda specialty coffee sector represents one of the industry’s greatest success stories — in little more than a decade, the country didn’t just put itself on the specialty coffee map.  It became a star — a reliable source of distinctive coffees and a seasonal mainstay on the menus of even the most discriminating coffee roasters.

The PEARL project, funded by USAID, joined by industry leaders like Geoff, and led indelibly by Tim, was a catalyst and central player.  Tim was honored in a special ceremony last year by Rwanda’s government for his role in the process.  Tim says he was touched by the gesture, but in the characteristic humility that has made Tim such an effective and beloved leader, he is quick to shift the credit to the Rwandans who have done all the heavy lifting.

Geoff echoes that sentiment in his commentary on our partners in Rwanda and the roles they played in the country’s coffee resurgence.  His account includes a very personal and emotional reflection on what it was like to work in a country shattered by genocide.  It comes in response to a question I ask, reluctantly and gingerly, about his personal motivations in Rwanda.

I am not sorry I asked the question, but I am still not sure it was the right thing to do.

The story of the country’s genocide isn’t really an essential part of the story of the country’s coffee sector.  Rwanda’s coffee is exceptional.  It is worthy to stand on its own without reference to the context out of which the country’s coffee sector emerged — you would buy it again and again just based on how it tastes, without the story of where it came from.  The risk in referencing that context is that it distracts from the coffee’s intrinsic quality.  That by refracting the story through the lens of our own perspectives, we rob Rwandans of the opportunity to tell their own story on their own terms.  Worst of all, there is the risk that the conversation will be seen as trafficking in other people’s suffering for our own purposes.

On the other hand, the story of the country’s genocide really is prelude to the story of the country’s coffee sector.  As Tim explains, the PEARL project was designed precisely to help foster the reconstruction of the rural economy and accelerate the country’s recovery from the unspeakable losses sustained in the genocide.  As Geoff explains, the long shadow the genocide cast over every aspect of life in Rwanda was an explicit source of motivation for him in his work.  While there may be some risk in referring to the genocide in this context, it seems that not acknowledging it is endlessly worse — oblivious to culture and context, insufficient to any appropriate appreciation of the coffees we source from Rwanda, and callous to the painful experiences of our supply chain partners and friends in Rwanda.  I hope you agree.

Listen to the Intelligentsia Buyer’s Notebook for Rwanda here.

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ECW: A ride on the magic bus

The Extraordinary Coffee Workshop is the annual gathering of our Direct Trade network.  It has become the anchor of our sourcing program and the most important event on our calendar every year.  But it wasn’t always that way.

Before 2009, our sprawling Direct Trade network was held together mostly by the heroic efforts and tireless travel of my colleague Geoff Watts, who for many years was the James Brown of specialty coffee — the hardest-working man in the business, on the road 250 nights a year, bringing it day after day.  He still finds the energy to grind at origin like people half his age, but for the last eight years, he has leaned a little on ECW.

Somewhere along the way, Geoff had an epiphany.  More like lots of little epiphanies that led to one Big Idea.  He would travel from country to country, farm to farm, mill to mill furiously snapping photos and scribbling notes that he would drill into his laptop every evening.  At each stop, he would crack open the laptop and try, with varying degrees of success, to use the images and words he had stored there to transfer insights and promising practices from one grower to another.  At some point, Geoff began to understand intellectually the limitations of the two dimensions of his computer screen as a learning tool.  He understood at a more visceral level the inefficiency of a retail approach to knowledge transfer that relied so much on his travel.  And he also appreciated the limitations of his own perspective as a coffee buyer — for all his understanding, he didn’t see things at origin the way growers did, which limited his ability to turn insights from one origin into action in another.  He started imagining, naturally, a magic bus that would carry all the growers he visited to one another’s farms so they could see what he did with their own eyes.  And ECW was born.

Today’s episode of the Intelli Sourcing Sessions is devoted to ECW. Geoff explains in more detail where the ECW idea came from and how it has evolved.  Camilo Merizalde, the enterprising Colombian grower who now operates coffee farms in Brazil, Colombia, Costa Rica and Panama, has participated in all eight events and hosted the inaugural ECW on his Santuario farm in Cauca.  He explains how that first event came together — and almost didn’t.  And participants in the most recent ECW in Costa Rica share their perspectives on what the event means to them.

Listen to the ECW episode of the Intelli Sourcing Sessions here.

To add the podcast to your feed, subscribe on iTunes or Soundcloud.