Extraction Curve Analysis

Extraction Curve Analysis

Lvl Up Coffee Hits High Scores In Normal, Illinois

Specialty coffee in the central Illinois town of Normal has reached a new stage of quality with the opening of Lvl Up Coffee Bar. Brought to life by coffee roaster…


Oklahoma’s T3 Roasters Completes a Historic Opening

Oklahoma-based coffee company T3 Roasters has opened a flagship brick-and-mortar roastery and coffee bar called T3 Coffee Co., inside a thoroughly remodeled historic building in downtown Collinsville. The building is…


Torr Launches the Hive Cafe Countertop Coffee Concentrate System

Commercial cold coffee equipment company Torr Industries recently rolled out a countertop-friendly version of its signature Hive Brew cold coffee system, called the Hive Cafe. The northern California coffee company…


5 Amazing Coffee Drinks in Reno, Nev.

Here are some standout specialty drinks you can try in the Biggest Little City in the World. BY EDDIE P. GOMEZSPECIAL TO BARISTA MAGAZINE Photos by Eddie P. Gomez Reno, Nev., has more cafés per capita than just about any other place in North America. And because it is a snowier-than-usual winter in northwestern Nevada […]

Extraction Curve Analysis

Three Questions with Gabriela Parfait of The Good Sourcing

After eight years working for the French green coffee importing company Belco, Gabriela Parfait has launched a coffee-focused company called The Good Sourcing.  The new venture is intentionally small, although…


New AFCA Director Gilbert Gatali on the 20th African Fine Coffees Conference

As the African Fine Coffees Association (AFCA) prepares for the 20th iteration of its flagship event, the African Fine Coffees Conference and Exhibition, the group is operating under new executive…


PRF El Salvador announces speakers and panellists

Following a call for applications in October 2022, Producer & Roaster Forum (PRF) has announced its first speakers and panellists for PRF El Salvador. The two-day forum will be held on 16 and 17 March 2023 at the Salamanca Exhibition Centre in San Salvador. The event is set to return to El Salvador after it […]


An Unfiltered History of Vietnamese Coffee

We explore the history of coffee in Vietnam and how the industry’s perception of Vietnamese coffee is evolving.  BY EMILY MENESES BARISTA MAGAZINE ONLINE Featured photo by frank mckenna via Unsplash What do you think of when you hear the term “Vietnamese coffee”? For Kim Dam, founder of Portland Cà Phê, it extends far beyond […]

Extraction Curve Analysis

Cup of Excellence to Offer El Salvador Immersion Program

The immersion experience will allow participants to grow their knowledge on Salvadoran culture and coffee varieties. BY J. MARIE CARLANBARISTA MAGAZINE ONLINE Photos courtesy of Cup of Excellence Cup of Excellence is launching a new learning opportunity in 2024: the Origin Immersion Program, to be held in El Salvador from February 26 to March 5. […]


Playing Leaderboard, the Arcade-Inspired Coffee Game

We sat down to try the newest version of the game—a fun opportunity to learn more about coffee while vying for cool coffee prizes.  BY TANYA NANETTISENIOR ONLINE CORRESPONDENT Photos by Tanya Nanetti I’ve never been much into video games, except for the classic arcade games of my youth.   Growing up in the ‘80s meant […]


Why it’s easier for wealthier producers to grow specialty coffee

It takes money – and sometimes a lot – to grow specialty coffee. Producers not only need to continuously maintain and improve quality and yields, but they also have to invest back into their farms. Whether it’s replacing equipment and machinery or planting more resilient varieties, producers need to turn a profit to operate their […]


Thread Coffee Roasters Opens Tailor-Made Roastery in Baltimore

The interwoven actions of Thread Coffee Roasters in Baltimore are finding exponentially more space this week with the grand opening of a brand-new production roastery and training lab. The worker-owned…

Extraction Curve Analysis

Extraction Curve Analysis

minimum dose size?

Jan 31, 2024 |

I use the Hario switch to brew my coffee and am trying to reduce my caffeine consumption. Hence I would like to brew smaller cups of coffee. I am currently using 10g of coffee with 160g of water. (1:16 Ratio) I am wondering if there is a minimum amount of coffee...

Extraction Curve Analysis

Most of my work over the past ten years has involved analyzing roast-curve data for clients. Those years spent analyzing tens of thousands of curves have helped me identify consistent, verifiable relationships between curve shape and cup quality. Regardless of a clients’ roasting goals, that experience has usually made it easy to help the client immediately improve upon a roast simply by looking at a curve and suggesting alternative settings.

As I gain experience on the DE1, I’m learning to read its tablet’s curves and benefit from them. Below is a discussion of the most typical curve shape (ie a bad one). I think of this shot as the espresso equivalent of a roast curve with an ROR crash and flick. Mind you, the art and science of analyzing extraction curves is much more immature and speculative than that of analyzing roast curves; we’re still deciphering what all of this means.

 

typical decent curve.png

 

This shot was generated using a flow profile. The green line represents pressure and the blue line indicates flow. The red numbers indicate important feedback.

  1. The volatility in the pressure curve indicates channeling during preinfusion. Despite being in flow mode— which helps “fix” channels as they form— a fair amount of channeling still occurred. I have little doubt this shot suffered from poor puck prep or too many clumps in the dry grounds.

  2. The collapse in flow after preinfusion likely indicates the grind is too fine (note the peak pressure of twelve bar), causing too much puck compression to allow the desired flow rate to occur. The high pressure could also be due to too large of a dose, but I’m assuming we use a consistent, appropriate dose.

  3. The phase from 25s to 40s where the pressure declined gradually is what John calls the “healthy extraction phase.” On some shots, the gradually declining pressure does, in fact, seem healthy— we believe it indicates no significant channeling while the puck erodes. On this shot, it’s debatable how much of this phase reflects “healthy extraction” and how much it indicates the puck is too compressed and/or still absorbing liquid (ie incomplete preinfusion). The steep pressure drop after #3 almost certainly indicates the formation of channels as the puck erodes.

    We are confident that we prefer shots with smoother pressure curves, steadier flow after preinfusion, more gradual pressure decline after the pressure peak, and smoother pressure curves. Those observations have proven valid in both directions— when we see those curve features, the shots generally taste better. And when we taste numerous shots of a given coffee, the best-tasting shots turn out to have had such curves.

    It’s still early days in my Decent Education, but the DE1’s graphs have already made me a better barista, and it’s a lot more fun and interesting to pull shots with the feedback of the DE1’s graphs.

    For reference, the graph below is what I would consider “excellent’,” and it coincidentally (?) looks quite a bit like a steadily declining ROR curve. Cropster for espresso, indeed.

great pressure profile curve.png

Extraction Curve Analysis

Perfect Little Beans

Chinmey Hill Coffee uses specialty-grade beans with zero primary defects (such as black beans or sour beans) and less than five secondary defects (such as broken beans). This is important because primary defects will greatly affect the taste of the coffee. Having zero defects allows the coffee to be the most optimal flavor.

Window for Optimal Flavor

Chimney Hill Coffee ships our coffee the same day it was roasted, so you will receive it before it enters the window of optimal flavor.  This means you’ll never miss the opportunity to enjoy the coffee’s peak flavor.

Coffee Ratings

Coffee undergoes many scoring processes by professionals who achieved their Q Grader certification. Coffee is first graded when it’s green. If there are defects the coffee is determined to be “not-specialty grade”. For those coffees that pass green grading, they are sample roasted and cupped. (Cupping is the official term for critically tasting and scoring coffees. The official cupping form is standard worldwide, and where the 100-point scoring system comes from.) A coffee’s dry fragrance, wet aroma, flavor, aftertaste, body, acidity, balance, and overall impression are taken into consideration while uniformity issues and defects, will lower the overall score.

Specialty Coffee

Specialty coffee, coined by Erna Knutsen in 1974, refers to a coffee that receives a quality grading score of 80 percent or higher. While “premium” or “gourmet” seem like they’re synonymous with “specialty,” they simply are marketing terms with no defined standards. Specialty coffees are grown in specific and ideal micro-climates, and have distinctive and unique flavor profiles, with little to no defects.

Third-Wave Coffee

We’re currently in the third wave of coffee. The first wave of American coffee put pre-ground, vacuum-sealed cans in kitchens across America. The second wave started with the late ‘60s introduction of Peet’s coffee (by Alfred Peet) through the proliferation of Starbucks. The third wave of coffee focuses on origin transparency, nuanced flavors, and artisan roasting. The term “third wave” is synonymous with specialty coffee.

Extraction Curve Analysis

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