Coffee roasting can be a tricky process. From selecting charge temps to calculating the proper drying times, every decision counts!
Here at Symmetry, we love the coffee roasting process! It enables us to carefully curate our own flavor profiles and draw out the potential in every bean.
Roasting plays such an integral part in every cup of coffee and that’s why we take the craft seriously. In a recent episode of our Coffee Shop Buzz podcast, we talk about the coffee roasting process and how it affects our final product.
The Beauty of Coffee Roasting
“Roasting in-house, we have the ability to control the flavor profiling of each and every coffee that we bring into this shop,” starts Ted Linn, owner of Symmetry Coffee & Crepes.
The beauty of roasting is that it enables you to make decisions that affect the most particular aspects of coffee flavor and quality.
“For us, roasting is a passion because it gives us more control over what we bring into the shop as far as the flavor goes,” says Linn “It means a lot to us when a customer says ‘Wow! This coffee is awesome!’ It means so much to us.”
Coffee roasting is essential to how we operate as a business. Our goal is to introduce our customers to the beauty and nuance of craft coffee. To us, it’s more of an art form than a commodity.
Many of our first-time customers are unfamiliar with third-wave coffee or craft coffee.
To properly introduce those customers to what coffee can be, we want to have total control over the flavor profile and quality of our coffee. That’s why we roast.
It’s incredibly important to us that the customer receives nothing but the best when they grab a drink from our shop or order our beans.
“So once we get a green coffee, what do we do with it? After we evaluate it, after we’ve done some sample roasting, and we decide that this is the coffee that we want to bring into the shop,” shares Linn “We submit an order, we sign a contract that we’re going to purchase this coffee…Once it gets shipped to us, the fun begins…”
Coffee Roasting: Evaluation Process
When we get our beans in from our suppliers, we have to take into account every aspect of the beans farming, processing, and constitution that might affect the roasting process. This can include:
- Growth Altitude
- Bean Density
- Bean Size
- Soil Type
- Organic vs Non-Organic Farming
Each of these can play a major role in how we choose to approach the coffee roasting process.
We sample every coffee before choosing to purchase. So typically, we’ll receive a 1 lb bag for samples which we use to determine if the bean is a good fit for our shop.
This is crucial as it allows us to roast it, cup it, evaluate, and make adjustments before roasting larger batches.
When we conduct our test batches we seek to answer a single question;
“What is the best output for this coffee? How are we going to get the best flavor?”
An integral part of answering this question is the cupping process. When we do a cupping process, it helps us to evaluate what needs to change whether it’s the charge-temp, airflow, drying time, or another aspect of the roasting process.
We tend to do about four different roasts for each batch to find what we like. And it’s often a 1/4 lb or 1/2 lb of beans.
We don’t always find that perfect match easily, however. Sometimes, we’ve run-through as many as six roasts and still haven’t figured it out. It can get tedious, but finding the right process is key.
Coffee Roasting Process
“We love the various different origins of coffee that we bring in here.”Ted Linn
Something that we’re partial to are the really sweet and fruity coffees. Some of the Ethiopians, some of the naturals, the honey processes. All this processing affects how we approach the coffee. And that’s what gives it a uniqueness, it’s flavor… I could go on for hours, if not days, on the technicalities of what happens in the coffee… But we’re gonna keep it simple. We want to give you a better understanding of what we’re doing here.”
The coffee roasting process is simple to understand but highly technical in execution. In this post, we’ll cover several key terms and phases integral to understanding coffee roasting:
- Charge Temp
- Turning Point
- Drying Phase
- Malliard Reaction Phase
- Development Phase
- First Crack
- Cooling Phase
What you do in each of these phases can drastically affect the flavor profile of the bean. Similar to a line of dominoes, each step directly affects what happens, or what is possible in the next phase of the roast.
In order to replicate our successes and avoid our failures, markers are placed on the graph during each roast as a reference for every adjustment made.
Every part of the roasting process is done manually, but the computer helps to log the process, record adjustments, and is available to use as a reference.
Also, throughout the roasting process, we’ll pay close attention to the smell of the beans for the different changes occurring. This helps us to know what’s going on.
We’ll use specific examples from an Ethiopian natural that we recently roasted throughout the remainder of this post to help better explain the roasting process.
For our Ethiopian example, we first started with a 390º F charge temp. Your charge temp (or drop temp) is the temperature at which your drum is set prior to dropping in the beans to initiate the roasting process.
Typically, a charge temp is set anywhere between 380º-415º F
Charge temps can vary widely based on what happens at the farm level: elevation, humidity, etc.
It plays a vital role in the overall flavor profile and largely dictates the curve of your entire roast. If you mess it up, you could easily miss out on the desired flavor profile.
For the first minute that the beans are in the tumbler, we cut the heat. At first, you will see the graph temperatures plummet.
Then you will see the curve starts to level as the bean temp and drum temp come to an equilibrium. This is referred to as the “turning point”.
The drying phase begins immediately following the turning point.
“For something like an Ethiopian natural, what we want to do is we want to approach it a little bit slower. We extend that drying time a little bit longer… probably the 5-5 1/2 minute range before we begin to call color change.”
Roasting coffee is somewhat analogous to grilling a steak. For a more well-done steak, you have to cook out the moisture with a longer, slower cooking process.
If the outside of the bean is cooked, but the inside is not, you’re left with a grassy note, which is not very pleasant for most coffees. So, properly drying your beans is critical.
After that first minute, we’ll turn the gas/heat back on to about 45% to maintain the curve.
After the drying phase comes the Malliard Reaction phase of the roast.
Malliard Reaction Phase
In the Malliard Reaction phase, we begin to see the beans transform! Webster defines the Malliard Reaction as:
A nonenzymatic reaction between sugars and proteins that occurs upon heating and that produces browning of some foods (such as meat and bread)Miriam-Webster Dictionary
“The molecular structure of the bean is changing. And that enhances the flavor, that’s when the flavor begins to start coming out.”
This phase is responsible for the characteristic flavor and browning we see in roasted coffee.
Now, the bean is beginning to darken in color, and you’ll start to hear a pop, we call this the first crack, we notate it and pay very close attention, smelling the coffee for its attributes. If it’s a naturally processed bean, we want to smell the sweetness.
First crack is where the coffee begins to audibly pop or crack. This cracking lets the roaster know that the development phase has now begun.
The second crack is a feature unique to dark or Italian roasts (more on that later).
The development phase can vary in length and changes from bean to bean, but always starts with the first crack.
Every step taken up to this point carries over into the development phase and affects the possibilities or the final profile. That said, this is where the flavor profile is fine-tuned.
You can follow the same roast process up to this point, cut your development phase by 30 seconds, and end up with a wholly different flavor profile.
Development happens very quickly and can have drastic results. A shorter development phase will lead to a brighter profile, while a longer development phase produces a darker roast with less acidity and more body.
Again, upon the occurrence of the first crack, numerous reactions will take place very quickly, so this point in the roast is critical.
During these crucial moments, we are waiting for peak aroma.
If left in too long, aroma will begin to fade and we lose it for good. If we miss it altogether, we’ll start over with a lower charge temp and draw out the roasting process to dry out the bean more thoroughly.
Once peak aroma is reached, we’ve completed the roast and it’s time to cool the beans!
In the cooling phase, the goal is to bring the beans down to room temperature as quickly as possible to halt the roasting process.
This step should take no more than 4-5 min. After this is achieved, the coffee is ready for use!
Variances in Coffee Roasting
Several other factors also play a role in how the coffee roasting process is approached.
How the bean was processed, the size of your batch, and the target roast style all play a part in how we plan the roast.
Our Ethiopian example was naturally processed, so it had plenty of natural sugars. Naturally processed beans can caramelize easily and put off a burnt caramel flavor, so that is important to watch out for.
The process changes for fully-washed coffee, you want to approach the first crack much more quickly, and have a shorter roast overall.
Each crop and processing style lends itself to a unique roast. As a result, one of the best roasts we’ve ever had was a honey processed Sumatra.
“We had to treat it very similar to a natural,” shares Linn “We started off really slow, but then we nailed it at the end… turned up the heat, and we rolled through the first crack really quickly…”
Each approach for roasting is different with each processing style.
When shifting from a test batch to a full batch, adjustments are made to account for the turning point, cooling time, etc.
Ensuring that the roast profile does not change when jumping to a full batch is the mark of a true roaster. It can be difficult to master, but ultimately yields more quality product.
Medium vs Dark Roast
Many customers ask why we don’t prepare dark roasts here at Symmetry. We can, but we tend to bring in coffees better suited for a medium roast. If we take that same bean and produce a dark roast we muddy those inherent qualities and flavor notes.
Truthfully, it’s just not our style.
“It really breaks my heart to see someone take a really good coffee and roll it into a dark roast. Because you’re missing out on what that coffee has to offer.”Ted Linn
90% of the hard work is done at the farm level, and we want to enhance what they gave us.
Furthermore, with dark roasts, the bean begins to collapse (signified by the second crack) and becomes oily, which can clog up the grinders (another reason we don’t go dark).
Coffee Roasting: A Labor of Love
“It’s difficult, it’s very technical, but at the same time, it has to be done,” says Linn “We want to make sure that this coffee is given its due justice. And, that the farmers are given their due diligence.”
At the end of the day, we want to ensure that every effort made in cultivating your cup of coffee shines through in our final product.
Stay Up to Date
For more helpful information on the coffee world, be sure to check out our podcast Coffee Shop Buzz (streaming on all platforms) and stay current with our regular blog posts!
Also, don’t forget to like us on Facebook and check out our online store where you can purchase Symmetry t-shirts, coffee-scented candles, stickers, and bags of our latest roasts!