Understanding Roast Color

Taking the color of a roast is quite simple nowadays. Just prepare a sample and point your roast color meter at it. The device will display the roast color as a number. This may raise some questions.

• Why do different devices report different results on the same roast?
• What does the reported number mean and how does it compare?
• Why does the same device report different numbers for the same roast?

This post resembles our report On Idle Noise, where we identified the sources of temperature measuring noise and quantified their impact. This post shares our observations from over 1000 color measurements taken with Tonino and Lighttells CM100+ roast color meters. Our results can help answer the above questions and may lead to better color measurements.

Artisan v2.6.0

 

We dedicate this release to the constructive ones, the creatives, the makers, the innovators, the open ones, the integrators, the ones that lead us forward to make this a better planet for all of us and put the destructive ones, the duplicators and obstructors to shame.

Artisan v2.4.6

 

Artisan v2.4.6 adds structures to calculate energy consumption and CO₂ production per roast.

Artisan v2.4.4

This version improves some established automation features to better support the control of preheat and between batches protocols.

Supporting Between Batch Protocols

Here is our response to Scott Rao's call out to makers of roasting software to offer structures supporting the tracing and managing of BBPs (Between Batch Protocols) and warmups.

How to Create the Perfect Background Curve

A background curve can act like a set of rails to ride while roasting. Roast masters often use a successful past roast as a reference in the background to follow and reproduce. This can be very helpful. Frequently the roasts available to use as a reference suffer from imperfections like RoR curves that show dips, crashes and flicks. A question we are asked is how to use an existing curve to create a "perfect" reference curve, a curve with straight line declining RoR using the event times and temperatures from an existing curve. This article will show one method to create a such a reference background curve.

Special Events Annotations

A common question asked when analyzing a completed roast profile is "what was the time and bean temperature when that gas change was made?"  To help answer this and similar questions, Artisan v2.4 introduces customizable, data driven special event annotations.  Special event annotations add detailed information in text format to the special event lines.  These annotations speed interpretation of a profile in post roast analysis by writing out the pertinent information directly on the graph. The user has broad flexibility when defining the text and data to be displayed.  This allows bespoke annotations that meet the user's individual needs.

Profile Transposer

The temperatures recorded and logged in profiles during roasts depend on the exact probe placement among other things like airflow. This makes it hard to compare profiles recorded on different machines. Luckily there are some points in a roast that can be identified based on physical changes of the beans during a roast, like the yellow point (DRY) and the start of first-crack (FCs). The recorded temperatures at those points can be compared and used to construct a mapping from profiles recorded on one machine to those on another machine. The profile transposer is a tool that supports the construction and application of such mappings along the temperature axis, but also along the time axis to extend or compress a profile.

Roast Comparator

While Artisan always allowed to load a second profile into the background, sometimes you want to compare the shape of more than two profiles. For this we introduced the Ranking Reports already in 2016 which allows to produce a nice Web page containing, next to sortable tables with the key data points of the selected roasts, a chart of all selected profiles. The drawback of this approach is that the report is static in that it is not possible to apply ad-hoc changes to navigate the representation. The Comparator allows to compare profiles dynamically.

Artisan v2.1

This is the Artisan version we will use to prove Scott Rao wrong (or right). We extended Artisan in various ways to facilitate the application of his roasting theory.  Thanks Scott, for pushing us!

Profile Analyzer

Roasters often want to analyze their roasts to measure consistency, look for aspects of the profile that can be improved, and to create metrics to score the roast against a set quality measures.  Artisan offers many ways to provide information on a roast.  These include the Statistics Summary, Plotter and Math tabs, AUC (area under the curve), and many others.

Artisan v2.1 adds a new set of features to provide additional insights.  These features continue Artisan's heritage of exploring new ways of interpreting roast data.

Background Images

Artisan v2.1 allows you to show an image in the background of your profiles. This can be any image you choose.  It could be a logo, a picture of your roaster or anything you choose.

Symbolic Formulas: Basics, New Variables and Applications

Each Artisan input channel can be intercepted by a symbolic formula before its data is forwarded to the corresponding curve. Symbolic formulas allow to change data retrieved from the input source before it is further processed, displayed and stored in the internal data structures. In that respect, the use of symbolic formulas is usually destructive to the original data received. From Artisan v2.1 on, symbolic formulas can also be applied to the two rate-of-rise channels.

In this post we recap the basics of Artisan's symbolic formula mechanism, describe the new variables that have been added in Artisan v2.1 and explain their interplay by discussing useful applications.

Artisan 2

Here is artisan 2!

How close?

Ever wondered how close you duplicated a previous roast profile? A standard measure in statistics to express the average error between a curve and its target is know as Mean Squared Error (MSE) which computes the average of the squares of the single discrepancies between the data values and their targets.

Keep an eye on the delta!

Once you have developed a profile for a coffee you want to precisely duplicate that one in future roasts. Artisan allows to load this successful profile in the background serving as a template for your production roasts. While seeing the delta of your current roast curve and that template helps you to decide if you should slow down or speed up your roast at any moment, especially if zoomed into the graph somewhat. However, often a numeric value expressing this delta is easier to work with. What about adding another LCD to show this delta?

On Idle Noise

This note describes how I improved the measuring system of my roasting machine to get more accurate roast profiles, like the one shown above. I got motivated by the work of Scott Rao.

Artisan v1.4.0

Here is Artisan v1.4. More than 30 bugs have been fixed w.r.t. v1.3.1 and many suggestions for improvements have been integrated, mostly communicated via our Artisan issue tracker.

UPDATE 17. October, 2018: Artisan v1.5.0 has been released with important bug fixes.

Artisan v1.2

Artisan v1.2 is a major release. The software on which Artisan is built was significantly modernised, especially on the Windows platform, resulting in better support of the current operating systems and hardware (e.g. high-resolution displays). A consequence of this move is that from now on, only 64bit operating systems are supported and compatibility with Windows XP and OS X before v10.10 has been dropped. Find below a description of the major changes and new features.

Roasting with Phidgets

An introduction to automatic roast logging using basic hardware from Phidgets in combination with Artisan. This article focuses on standard USB Phidgets that have been supported by Artisan since 2013. The follow-up post More on Phidgets! describes the extended Phidgets support by Artisan v1.2 covering also the new VINT devices that were introduced at the end of 2017 by Phidgets.