RoasTime is Aillio’s proprietary roast profiling software. You can use the software to both monitor and control your roasts on the Aillio Bullet R1. It is 100% free and version 2 is available for Mac, PC, and Linux systems.
Some aspects of roast profiling are counter-intuitive, so if you’ve never had a roast profile explained to you before, it is easy to feel a bit lost when looking at one. With that in mind we’ve created this guide to help get you started. It will include a run-down of some of software’s UI, as well as some basic ideas about how the Bullet R1 works, and also how to put your roasting data to the best use through profile analysis.
Please keep in mind that RoasTime is a work in progress, with new features being added on a regular basis. This guide assumes you have already read the manual and our basic guide to roasting coffee, How To Roast Great Coffee On The Bullet R1. At the time of this writing the latest stable release of RoasTime is version 2.2.0. We will update this article accordingly as new releases emerge and new features are added.
How Do I Get Started?
If you haven’t already, you will need to download and install RoasTime 2 (RT2). Head to https://downloads.aillio.com and select the version that is right for your computer. When you install the software, be sure that your Bullet R1 is plugged in, in off mode, and that it is connected to your Mac or PC via the micro-USB behind the control panel.
On Windows you will be prompted to install the USB drivers, but in order to install the drivers correctly the Bullet R1 *must* first be connected via USB. If for some reason the driver installation is unsuccessful, you can try again by selecting “Force Update Drivers” from the “Tools” menu in RoasTime, again with the Bullet R1 connected via USB.
Once RoasTime is up and running, you should log in with your Aillio ID. Keep in mind that this ID is not the same as your www.aillio.com login.
Adding Beans To RT2
If you wish to share and compare your roasts with others, or if you plan to take advantage of inventory tracking, then it’s a good idea to add your beans to RT2. You do this by first logging into Roast.World with your Aillio ID and selecting “Find Beans” from the Beans menu on the left.
If you purchased your beans from a vendor that already exists on Roast.World, you may discover that your beans have already been added by someone else. Otherwise, you can create the bean (or even the vendor) yourself.
Once you find or create the bean, you must add it to your beans by clicking the “Add to My Beans” button.
After you have added the beans to your list on Roast.World, you will be able to attach them to your future profiles in RoasTime 2. (You can also add beans you’ve already roasted, and then attach their names to your profiles at a later date, either within Roast.World or in RT2.)
Please note that in the coming weeks and months, Roast.World will undergo some dramatic changes in both look and functionality. We will be updating this guide accordingly, as well as producing a separate guide for the platform.
Once you’ve added your beans, it’s time to..
Preheating the Bullet
Set a preheat temperature on the control panel of your Bullet R1, and either press the PRS button on the control panel or press the “Start Preheating” button on RT2.
As shown in the image above, you can monitor the Total Preheat Time, the Bean Temp (taken from the traditional bean temperature probe), the ROR (Rate of Rise, again taken from the traditional bean temperature probe), and the IR Drum Temp. We’ll discuss each of these values below.
“IR Drum Temp” During Preheat
The IR stands for infrared. All Bullets, from the very first pre-order V1s to the latest V2 units, utilize infrared to measure the preheat temperature of the drum. As it heats, the Bullet will ‘overshoot’ the selected preheat temperature by about 5 degrees, before attempting to re-stabilize to the set temperature. At this point, the Bullet will be nearly ready to roast.
“Bean Temp” During Preheat
Of course, there are no beans in the drum during preheat. But as the drum heats, the air inside of the roaster will also heat up, causing the temperature of the bean probe to rise. We’ve had many roasters use this bean temperature reading while preheating as a sort of proxy for the total amount of thermal energy stored in the drum, but we don’t believe this to be very effective, as there are a great many factors that may affect the bean probe reading, none of which have much to do with how ready the Bullet is to roast. Ambient room temperatures, airflow in the drum, previous roasts (when back-to-back roasting), etc… will all affect the bean probe. So if you see a roast recipe calling for a certain bean probe temperature before charging, you should not worry about matching it. Just wait for the “Charge” command from the roaster, or make sure the IR drum temperature is the same and that the ROR has stabilized. Speaking of ROR...
“ROR” and “Total Time” During Preheat
The ROR (Rate of Rise) value is given in degrees Celsius (or Fahrenheit), per minute. It’s an indication of how quickly the bean probe is heating up (or cooling down). We will discuss ROR at length a bit later, but while preheating, it gives us a rough idea of whether the Bullet has warmed up enough. The ROR will begin high and slowly fall, until it reaches a stasis with the thermal energy being fed into the drum. At this point, with an ROR consistently in the vicinity of 0, the roaster is ready to charge.
Charging the Bullet R1
To “charge” the roaster means to put the beans in it. There are two ways for the Bullet to enter Charge mode: automatically and manually. The Bullet will automatically enter charge mode once the target preheat temperature is met and the Bean Temp ROR stabilizes, or after the roaster has been preheating for a minimum of 25 minutes.
Alternately, you can manually enter Charge mode by pressing the PRS button on the control panel, or by pushing the “Charge” button in RT2.
When you drop the beans in, the Bullet R1 will automatically detect them and enter Roast Mode.
Roasting Mode in RT2: Roast Profile Creation
Once you begin roasting coffee, RT2 will begin recording the bean temperature and other data and milestones across the timeline of the roast. Everything will be logged and plotted in real time. Taken together, this is your ‘Roast Profile’.
Huh? Why Are There Two Different Bean Temp Readings?
Once in Roasting Mode, you’ll notice that the panel to the top and left within RT will change. In roasters with the IBTS (V 1.5 and V2, or for those who purchased the IBTS separately), the “IR Drum Temp” value will now display as “IR Bean Temp”, which is a second bean temperature reading.
The Bullet R1 V2 ships with two different sensors used for detecting bean temperature. Whenever you see “Bean Temp” by itself in RT2, it is referring to the measurement given by the traditional bean probe. This is the same basic kind of probe used in all other roasters around the world, one that produces a ‘traditional’ roast profile curve. These probes have been in use for decades, and while they certainly help roasters learn more about roasting, the data they give is of limited use. Traditional bean probes are slow to warm up, which means they always lag behind the real temperature of the beans, and their readings are also influenced by many other variables, from charge weights to ambient temperatures. They are, in short, unreliable.
The Infrared Bean Temperature Sensor, or IBTS for short, works in a fundamentally different manner. It uses infrared to measure the temperature of the beans directly, with no lag. This means both greater speed and higher accuracy. You can toggle between the two Bean Temp readings on your Bullet R1 by hitting the “A” button on the control panel. When the “X” light is lit up, you are viewing the IBTS reading. Otherwise, you’re looking at the traditional bean probe.
(We will discuss the IBTS more in this article, under the heading “Reading Your Roast Profile”. You can also check out our article about the invention of the IBTS, “The Start of Something”.)
Making Real Time Adjustments
Your Power, Drum, and Fan settings are all on display on the left panel of RT2. You can make adjustments directly from the software, or, alternately, you can press the corresponding buttons on the Control Panel. Either way, RT2 will always display the current values here. Changes you make will be logged on a timeline shown beneath the Roast Profile, as shown in the image below.
And above the Roast Profile graph, you will find some other values you may find useful, depending on how you prefer to roast:
“TS-FC” stands for Time Since First Crack. This is useful for users who roast their beans for a certain amount of time past First Crack. For example, you may choose to drop the beans 45 seconds after First Crack begins.
“DV” stands for Development. This is a measure of the total amount of time past First Crack divided by Total Roast Time. This is useful for roasters who are shooting for a specific Development %, believing it is an indicator of how developed or “done” a roast is. Opinions about the ideal development time for a specific bean may vary from as little as 6% to as much as 25% (or more), and they largely depend on personal tastes.
“DT” stands for Delta Temperature. It is a measure of how many degrees the bean temperature has risen since First Crack. Again, this is a value that some roasters rely on to measure the ‘doneness’ of their roast. Keep in mind that for now, this value is still derived from the traditional bean probe, but in future releases we plan to include the IBTS readings.
Speaking of First Crack, you can mark it and other roast events directly within RT2. The Event Marker appears below the Roast Profile. By pressing the buttons as events occur, you can log them. It’s up to you which events you wish to log, but generally speaking every roaster should probably be marking First Crack, either by pressing the button in RT2 or by pressing and holding F1 on the control panel. By the way, if you have no idea what First Crack is, then we invite you read both the “Manual” and also “How To Roast Great Coffee on the Bullet R1” before continuing!
Reading Your Roast Profile
As briefly mentioned above, a Roast Profile is a graph of bean temperature over time. It is in many ways the bread and butter of data-driven coffee roasting, but if you’ve never seen one before it may appear a little confusing. Let’s break it down for you.
What Am I Looking At?
The X-axis is time. The Y-axis is temperature. The secondary Y-axis, to the right, is the derivative temperature, otherwise known as the ROR value.
There are three lines plotted simultaneously. The blue line is the new IBTS bean temperature reading (or the IR drum temperature, in older models.) The purple line is the traditional bean probe temperature reading. The squiggly red line is the ROR.
Purple vs Blue: Traditional Bean Probe vs IBTS
Let’s talk about why they look different from each other. The traditional bean probe heats up during preheat — in this case it was about 125 degrees when I charged 350g of Ethiopian beans into the drum. So you can see it begins the roast at that temperature. When the probe makes contact with the room temperature beans, its temperature falls. But as the bean probe cools down, the beans themselves are actually heating up, and at a certain point, known as the “turning point” of a roast, the beans reach the same temperature as the bean probe itself, and from that point onward begin to heat it up. From there on, the curve is positive. In this particular roast, the turning point event took place just before 1:00.
The very existence of a turning point is a concrete example of traditional bean probe limitations. The beans, of course, do not begin the roast at 125 degrees Celsius, cool down, and then rise in temperature. They begin at room temperature, and as soon as they enter the drum they begin heating up. Traditional bean probes, however, are unable to capture this change directly. They store thermal energy during the preheat, and then are simply too slow to adjust.
Compare this to the IBTS reading (blue line) above. As it moves from measuring drum temperature to bean temperature, the reading it gives rapidly drops to that of the beans— room temperature in other words. This completely eliminates the data artifact known as the turning point.
As mentioned above, the traditional bean probes are also influenced by other factors. Because the traditional bean probe is merely a proxy for the actual bean temperature and requires the beans to transmit heat to it via conduction (contact), it will be heated up more quickly if you charge more beans into the drum. Anyone who has roasted batches of different weights on the Bullet — or any other roaster — will tell you the apparent First Crack temperature will vary wildly, with larger charge weights showing higher First Crack temperatures. But all of that data is wrong. The beans are cracking at about the same temperature, the probe just cannot give an accurate reading.
The IBTS, on the other hand, is simply taking a real-time measurement of surface bean temperature. This means that it doesn’t matter whether you’re roasting 300g or 1000g, First Crack is going to occur at the same temperature. The speed, accuracy, and consistency of the IBTS from batch to batch is an incredible learning tool for roasters.
What is ROR?
As stated above, the ROR is the squiggly line that emerges after the Turning Point. We briefly discussed ROR in terms of Preheating above, but it’s used quite differently while roasting coffee. The ROR is the mathematical derivative of the bean temperature, meaning it shows the slope of the bean temperature curve. A value of 0 means the slope is flat and the temperature has stabilized. A high value means the temperature is rising rapidly. An ROR of 10 means the bean temperature will rise 10 degrees in 1 minute.
Why does it begin at the turning point? Because, for now, the ROR generated by RoasTime is calculated by using the traditional bean probe, and when you first drop the beans the ROR is actually negative. This is because, as we mentioned earlier, the beans actually cool the probe down when you first drop them in the drum. After the turning point, the beans begin to heat the probe, heating it quicker and quicker before peaking — usually at around 15–23 degrees Celsius. The ROR should then begin to decline.
Among specialty roasters, a lot of attention is given to that declining ROR. It is widely believed that a slow, ever-declining, positive ROR is the hallmark of an excellent tasting roast. Roasters are also generally taught that a flat-lining ROR of 0 or below at the end of a roast will result in ‘baked’ flavors — a general dulling of what makes specialty coffee interesting. Whether all of this is true or not is perhaps up for debate, as the ROR has always been based off rather unreliable data from too-slow traditional bean probes. In other words, many roasts that appear to have a positive ROR at the end of the roast may have already flat-lined.
In the future, we hope to explore some of these ideas more closely with ROR data derived from the IBTS. Perhaps we’ll discover that a smooth declining ROR isn’t what’s most important, or that “baking” the roast at the end is technically not such a big deal after all. For now, rather than relying on ROR data alone to guide your roasts, we recommend keeping a close eye on the IBTS temps and let your taste buds be the judge of what is successful and what is not.
Your Roast History
Once you’ve finished a roast, it will appear in your roast history. You can access this screen by clicking the Roast History menu icon on the top left in RT2 :
From here you can quickly sort and view all of the roasts you have completed while logged into RT2, including the name of the roast, the bean used, the total roast time, the green weight, and the date.
By clicking the “eye” icon to the right, you can also preview the Roast Profile:
Other Features… (How Do I…?)
Overlay a Profile
Let’s say you’ve nearly perfected a roast profile for a particular bean, but you’d like to make a few minor tweaks. Or maybe you want to compare your next roast with one that you’ve downloaded from Roast.World.
You may find it useful, then, to overlay a profile on top of your live roast. To do this, you must select “Overlay Profile” on the top right of the Preview Profile or Full Profile screens. When you move to the Roasting screen, you’ll notice that you are now in Overlay mode, with the previous profile now visible.
Playback a Profile
Perhaps you’ve already perfected a roast, or maybe you’ve downloaded one that you believe will work for a particular bean. You can automatically playback a profile by clicking Playback, again on the top right of the Preview Profile or Full Profile screens.
The Playback feature will replay all changes made during the roast. It is based on Time only. If you want to edit the Playback to be based off temperature, you will need to use the new Recipe Creator, for now only available in Beta.
Edit a Profile
To edit a profile, click the Edit button while in Full Profile view. You will be able to adjust everything from the name of the roast to First Crack times. But you will not be able to edit profiles that you have downloaded from others.
Delete a Profile
If you don’t want to keep a particular profile, you can delete it on the Edit Profile screen. Again, you cannot delete profiles that aren’t your own. If you wish to Undownload a profile, you can do so at Roast.World.