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Heating Rates – Rising Interest from Coffee Roasters

November 24, 2015

There is no denying that the science and experimentation of coffee roasting are alive and well within the industry these days.  The tinkering and optimizing remind me so much of the so-called maker movement. One of the most heralded terms being batted around these days is heating rate, or rate-of-rise as it’s commonly referred.

What’s in a name…

Whether you prefer to call it the rate-of-rise/R-o-R/RoR, or our preference: the heating rate, understanding how quickly the temperature of the coffee beans rises and falls during roasting is arguably as useful if not more than recording bean temp by itself.  Who would have guessed a little bit of simple high school calculus could be such a game changer?  So, with all the attention it seems to be getting these days, we thought it was worth exploring this key RoastLog feature.

Much of the buzz around heating rate is being generated by members of the roasting community. In fact, it’s difficult to attend a specialty coffee conference, Roasters Guild retreat or coffee roasting event without it coming up in discussion – and for good reason, as it’s proven its worth as an invaluable tool for guiding roast profile development and understanding the unique characteristics of one’s own roasting equipment.

Logging heating rate:  A perfect complement to recording air and bean temp

Understanding heating rate, merits some talk of tracking enviro air temp in addition to bean temperature on drum roasters. A few years back, we hosted a guest blog post about how the interplay between bean and air temp provided insights into the thermal dynamics of roasting equipment and helped roasters anticipate how quickly heat applied to the drum will translate to the beans.

When we introduced our first 4-input data bridge we were finally able to equip our users with the logging device needed to simultaneously record both bean and air temps.  Since the air in the drum is much more responsive to changes in airflow and gas pressure, the environmental air temp in the drum is a bellwether for heat transferring from the system into the beans.

Adding in the heating rate/RoR completes the air temp/bean temp/heating rate trifecta, allowing roasters the ability to get realtime feedback on their flame adjustments and to see how rapidly bean temp changes during roasting.


Heating rate as recorded in the iPad app.

It’s worth reiterating that RoastLog users have the ability to visualize this information while actually roasting which, in turn, makes this info actionable.  As a result, roasters gain yet another tool in the effort to get consistency and quality from their roasting operations.

The value of monitoring heating rate

Knowledgable folks like Morten Münchow espouse the benefits of tracking the rate of temperature change when performing roast profile analysis and while dialing in roast profiles. In fact, one of the clearest explanations I’ve seen for heating rate/RoR – and the value of tracking it during roasting – is on Münchow’s blog at  However, he’s not alone amongst the evangelists.  Profile analysis and development have become staples during coffee roaster trainings. Numerous coffee courses including, but not limited to, Coffee International, Boot Coffee Consulting and regular offerings from the Roaster’s Guild cover the topic. One need not go much further than Scott Rao’s book, The Coffee Roaster’s Companion, for what amounts to a clinical dissection of heating rate and it’s impact on roast development – one the main pillars of Rao’s Three Commandments of Roasting.

Tangential lines representing heating rate at points along the profile. Courtesy Morten Münchow,

Coffee roasters are increasingly using these types of tools to better understand and anticipate the progression of their roasts.  With these tools comes control, clarity and a way to measure what previously was observed empirically. A perfect example is how heating rate informs roasters on how/when to adjust the application of heat to avoid pitfalls such as stalling and scorching.  These were events that, not very long ago, were things that a roaster was more likely to sense than measure.

More insight translates to better control and the ability to optimize the energy going into the roast.

In turn, a new generation of roasters is emerging – many who are honing their skills and mastering a craft in an incredibly short period of time. We’re generating a vast body of knowledge around roasting that is systematically raising the bar on coffee quality.  We’re just happy that we get to be a part of this movement.


Air Quality Management Recordkeeping via RoastLog

November 13, 2015

We’ve long promoted RoastLog as software designed for running your business.  So while RoastLog is probably best known as a tool for developing and logging roast profiles and managing green coffee inventory, did you know RoastLog is used by many roasters as part of their air quality management program?


Roasting coffee is fundamentally a combustion reaction and combustion by-products are created in the process, e.g., NOx, CO, CO2, SOx, formaldehydes and acetaldehydes, in addition to particulate matter, volatile organic compounds and organic acids¹.  These emissions constitute air pollution.  In the end, it’s all part of the reality of being a coffee roaster.  Balancing the desire to help speciality coffee meet it’s full potential while still taking measures to minimize the carbon footprint of coffee roasting, is one of the many challenges we see our customers grappling with – especially in North America² and Europe³.

Afterburners are recognized as an effective means to reduce the particulate emissions of roasters.  Roasting equipment continues to evolve and while technologies do exist that produce a cleaner roast, we all know that there is a significant portion of our industry that prefers using vintage roasters.   Until newer technologies become more accessible/affordable – and more prevalent as a result – afterburners appear to be the state-of-the-art for those who want to reduce the emissions from their “tried and true” roasters.  (Incidentally, none of this even touches the ongoing debate about diacetyl levels from roasting4,5)

(Screenshot) Afterburner time/temp profile (green) logged simultaneously with roast profile.

Afterburner time/temp profile (green) logged simultaneously with roast profile.

Then, there is the matter of ensuring that afterburners are functioning to specification.  Moreover, many locales and municipalities mandate logging afterburner temperature as part of air quality management record keeping. For years, chart recorders have been the go-to for this purpose.  RoastLog replaces conventional chart recorders in a reliable and automated fashion.  Worrying about running out of chart recorder paper or discs – only to find out several roasts or even days later – are a thing of the past.  In RoastLog, afterburner temps are logged simultaneously with each roast, eliminating the need to manage chart recorder records separately from roast logs.

Chart recorders can be costly to maintain, finicky and consequently expensive if they malfunction.  It’s been reported that some air quality districts issue daily fines when there are no afterburner records.  If you use RoastLog, and operate in an area that requires proof that afterburners are operational during roasting, the ability to log afterburner temp is built-in and can be added by simply installing a thermocouple.


  1. Lee, MKC. (2015, May 4). Permit Handbook, Bay Area Air Quality Management Engineering Division. Retrieved November 12, 2015, from
  2. Duggan J.  (2013, July/August). Smoke in the Air – An Update on Emissions and Air-Quality Regulations.  Roast Magazine, 22-32.
  3. Neill, J. (2015, April 1). How Roasters Stay Ahead of Air Quality Rules. STiR Tea & Coffee Industry International.  Retrieved November 12, 2015, from
  4. Rutledge, R. (2015, June 20). Coffee roasters’ health at risk from toxic compound, air samples suggest. Retrieved November 12, 2015, from
  5. Flavorings-Related Lung Disease – Coffee Processing Facilities (2015, September 29) Retrieved November 12, 2015, from  CDC (Centers for Disease Control and Prevention)

RoastLog compatibility with Phidgets

November 2, 2015

It’s official!  RoastLog is now available for use with the Phidgets 4-input Temperature Sensor.

This is something we wanted to do for quite awhile.  Compatibility with the Phidgets device simplifies the transition to RoastLog from other software systems and opens up an affordable option for home roasters who may have already invested in a data bridge and thermocouple(s).

Phidgets sensor with acrylic enclosure from

Phidgets sensor with acrylic enclosure from

RoastLog was originally designed as a closed system utilizing our own hardware (initially, the 1st generation 1- & 4-input Data Bridges; and now, the 4-input Bluetooth device).  After thoroughly testing the Phidgets, we feel confident in its performance.  Moreover, the integration with RoastLog creates the same quality experience and reliability our users have come to rely on.

We’re pleased to be able to provide another option to our users.  For more details on connectivity with existing Phidgets temperature sensors, contact us.

Exploring Roast Development Time

October 12, 2015

Practical applications of RoastLog’s Roast Development Timer

There are a lot of folks out there espousing various ‘Truths’ when it comes to coffee roasting, roast profiling and ‘the right way to roast’.  As a mere part-time roaster, I’m not only unqualified to weigh in on this debate, but like most things coffee… I say, whatever floats your boat.

That said, I have enjoyed and benefited from Scott Rao’s* perspectives on roasting.  Awhile back I stumbled on his comments in an article over at and thought I’d share as it relates directly to a feature in our new RoastLogger app for iPads, the Roast Development Timer.

When roasters manipulate development time without considering it in the context of the total roast time, they often create baked flavors and destroy sweetness.  – Scott Rao

Roast development time is not necessarily a new idea per se, but what I appreciated about Scott’s take was the notion of looking beyond the traditional view of roast development time.  Simply considering the total time spent in the roast development phase alone seems to paint an incomplete picture.  His idea takes into account the amount of time spent in roast development as a fraction of overall roast time.

This makes sense to me, at least intuitively.  Perhaps this is for the same reason that we thought our users would like to have a way to quantify the amount of energy introduced during their roast.  The concept we coined as roast energy seems to follow the same logic.   But is it reasonable to generalize an ideal amount of time (20-25%) as Scott suggests?

RoastLog's Roast Development Timer

The Roast Development Timer found in the RoastLogger iPad app.

It goes without saying, a lot goes into pulling off a good roast.  How important is the roast development phase in your roasting?  As a RoastLog user, would displaying the percentage be helpful?  We try our best to be conscientious about complicating our user interface.  Would we be muddying our UI by adding this or would it be insightful?

*Scott Rao is author of multiple books about coffee roasting, brewing/preparation and offers consulting services.  His most recently published book, “The Coffee Roaster’s Companion” includes a compilation of his observations, ideas and experiences roasting coffee.

Roast Profiling Has Never Been Easier

October 2, 2015

The first wireless Bluetooth data logger dedicated to coffee roasting

Manually recording time/temperature on graph paper was rendered obsolete when RoastLog was introduced a few years back.  Now, in that same vein, tracking the progress of a roast has gotten a lot easier and doesn’t require being tethered to a laptop or computer.   As any large-scale roaster will tell you, attending to a laptop isn’t always practical in a production environment – yet we know that keeping you connected with your roasting is always a priority.  We took this as a challenge to develop a better system for making sensory observations and data recording.

Our solution:  A brand new iPad version of RoastLogger that uses Bluetooth LE (low energy), also known as Bluetooth 4.0, technology to communicate with the RoastLog Data Bridge.

iPad RoastLogger and wireless Data Bridge

Roasting coffee with the wireless Data Bridge. Note there are no wires connected to the iPad.

From a software perspective, developing a brand new iPad application gave us a chance to revisit over four years of lessons from our existing RoastLogger application. The new RoastLogger iPad app is our tool designed to make it easy and intuitive to explore and develop roast profiles. Doing away with a mouse and keyboard really helps productivity in an environment like roasting coffee.  Users won’t need to make the clumsy context switch between a computer and roaster… logging actions are easy and a few simple taps away.

The biggest challenge for us was cramming all this new functionality into the product while maintaining a simple interface. In the end, it took a little longer than we anticipated, but I think we’ve succeeded on improving our popular RoastLogger program.

New Sensors
Developing a brand new circuit board to support wireless connectivity gave us a chance to add even more enhancements. This new platform adds barometric pressure and humidity sensors, giving roasters the chance to automatically record two completely new data points.

iPad RoastLogger saved roast

iPad RoastLogger screenshot at the end of a roast. Note the humidity and barometric pressure readings in the lower right corner.

As with any controlled process, roasters need to consider the impact of as many variables as possible.  Environmental factors can and do affect the roast.  In some parts of the world this includes seasonal climate changes and local weather conditions.  RoastLog now tracks these conditions at the time of the roast for comparison with historical and future roasts.

Heating Rate
In addition to the displayed value for heating rate (sometimes referred to as rate-of-rise), we’ve added this into our charts in the form of a plot.  This metric is commonly used to get insight into a roast in progress.  Super valuable for avoiding stalled roasts and insightful for making comparisons between different roasted batches.

Roast Energy

A unique way from RoastLog of representing the amount of energy inputted into a given roast.  It’s also handy for understanding milestone events by adding a dimension beyond time & temperature, e.g, the roast energy from drop until first crack or between the beginning/end of first crack.

Roast Development Timer

This timer was developed to give users the ability to monitor the amount of time spent in arguably the most import phase of the roast, the roast development phase.

Access over the Internet

As a cloud-based solution, RoastLog continues to provide access to all of your roasting data anywhere you can connect to the internet.

Growing interest in roast profiling fueled the adoption of RoastLog when it launched in 2011. We’re excited to continue to provide innovative solutions to meet the requests of our users.  The roasting community has spoken – and the consensus seems to be that roast profiling is helping to improve the quality and consistency of roasted coffee available today.

The iPad app can be found in the App Store.  Feel free to contact us for more details on how to get the new wireless data bridge.  Thanks for your continued support!

What are You Drinking?

September 29, 2015

If you’ve been considering RoastLog for awhile and needed a little nudge, here’s your chance.

In recognition of all the efforts to bring amazing sustainable coffee to the masses, and to celebrate International Coffee Day, we’re offering two free months of RoastLog** to all new subscribers.  Tweet us a photo of what coffee you are enjoying today #NationalCoffeeDay and mention us (@RoastLog) on Twitter. It’s that easy.

Here’s what I’m drinking!

Honduras Finca Zulema, Norma Zulema Azucena from Sightglass

Honduras Finca Zulema, Norma Zulema Azucena from Sightglass, San Francisco

Thanks for all the support.

Read more…

We Love Coffee

September 29, 2015

Today is International Coffee Day.  We’ll take every excuse, ahem, opportunity to celebrate the beverage we love.  You can bet there is going to be a lot of free or discounted cups of coffee served today, but beyond taking a moment to enjoy this beloved drink, please join us in raising awareness around the social and environmental issues related to coffee.

Check out a few of our favorites:

  • Cafe Feminino – helping deliver health and education services to the women & their families in coffee growing communities
  • Coffee Kids – promoting health, education, food security, and economic diversification in coffee-farming communities in Latin America
  • Grounds for Health – providing cervical cancer screening & prevention services in low & middle income countries

Here are just a few examples of our coffee industry friends using coffee to do good!  Love it!

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