What Goes Into Coffee Roasting?
Luke (the founder) explains what goes into coffee roasting and how the process works at the Lab.
Coffee roasting is known in the industry as being the most delicate part of the coffee production process. It requires precision, skill, and attention. Some would say it takes that certain je ne sais quoi, but I couldn't tell you 😉.
The first step in any coffee roast happens before the green coffee (that is, coffee that is not roasted) even arrives. See, coffee goes through a multitude of processing steps after harvest. Coffee starts out as a fruit called a "cherry" which is picked once ripe. The ripe fruit then sits for a bit to make it easier to split the coffee bean (actually a seed, if you want to get technical) from the cherry. A machine removes the coffee bean from the cherry. After that, there are a few differences in production technique, but all end with dried, ready-to-roast coffee.
Green coffee is, well, green. It tastes nothing like any coffee you've tried and seems pretty uninteresting. That's because none of the flavor compounds that give coffee its characteristic flavor have even formed yet. They all form during roasting. Otherwise, you're left with a grassy, planty, and useless caffeinated bean and nobody wants that. So, how do we roast, exactly?
Roasting is difficult for a few reasons. First, it's highly variable. Just a 10 second difference in roasting time can completely change the flavor. That's why it's critical to pay attention to detail. However, the two main factors at play that make up a majority of the predictive power in terms of knowing what a coffee will taste like are color and development time. Color is simple enough; it's just how dark the beans are. Development time takes a bit of explaining though.
Green coffee is about 10% water or so. During roasting, this water evaporates into steam. Meanwhile, gases are also produced inside the coffee, namely, carbon dioxide. These gases can build up to incredibly high pressures within the bean. Eventually, the bean has to let out the gas and the way it does this is by rupturing. That rupturing makes a signature cracking sound we roasters call "first crack". First crack is a sign that the moisture has left the coffee. Water has a tendency to absorb heat, so until all the water is gone, the beans stay cool. Once all the moisture is gone, it means the coffee can finally begin browning. The time after first crack is what we call "development time".
Now during development time, there are some important chemical reactions going on. Namely, Maillard (pronounced "my-yard") reactions and caramelization reactions. Maillard reactions happen when carbohydrates (sugars) react with amino acids (the building blocks of proteins). These reactions cause a browning effect. They're the same reason bread turns brown in the oven. The second set of reactions is caramelization reactions. They break down sugars into more basic components, creating important flavors like toffee and caramel notes. It's important to know: these reactions happen quite fast. Within 15 seconds, a coffee can go from tasting fruity and sweet to chocolatey and toffee-like. Flavors snap in and out of existence at any moment, and it's the roaster's job to make coffee that is consistent batch-to-batch. This can be incredibly difficult and it's why here at Vezpa, we have to go to technical extremes to make sure our batches are perfectly consistent. That means following tight temperature curves and constantly checking the color of the beans to ensure they're exactly what we want.
Now, a roaster typically looks something like a steel rotating drum and some sort of heat source (ours is infrared, for the best temperature control and distribution). As the drum rotates, coffee is mixed and churned so that every bean has a uniform color. In the drum, there's a sample spoon that collects roasting coffee that we can pull out and check to see how the coffee is browning and seeing when exactly we need to remove the coffee from the roaster. The process is meticulous, but it has to be in order to make the most consistent coffee. Strict temperature curves are followed for batch-to-batch consistency.
The final result is a coffee that we spent hours perfecting. In just ten short minutes, green coffee is turned from something rather useless into something not only drinkable, but remarkably delicious. It's a process we take incredible pride in here at the Lab. Rest assured, the hands behind the brand are working hard to deliver you the best coffee possible. Always small-batch, always transparent, and always done with love and care. I sincerely hope you enjoy it.
Happy coffee drinking,
Luke
The first step in any coffee roast happens before the green coffee (that is, coffee that is not roasted) even arrives. See, coffee goes through a multitude of processing steps after harvest. Coffee starts out as a fruit called a "cherry" which is picked once ripe. The ripe fruit then sits for a bit to make it easier to split the coffee bean (actually a seed, if you want to get technical) from the cherry. A machine removes the coffee bean from the cherry. After that, there are a few differences in production technique, but all end with dried, ready-to-roast coffee.
Green coffee is, well, green. It tastes nothing like any coffee you've tried and seems pretty uninteresting. That's because none of the flavor compounds that give coffee its characteristic flavor have even formed yet. They all form during roasting. Otherwise, you're left with a grassy, planty, and useless caffeinated bean and nobody wants that. So, how do we roast, exactly?
Roasting is difficult for a few reasons. First, it's highly variable. Just a 10 second difference in roasting time can completely change the flavor. That's why it's critical to pay attention to detail. However, the two main factors at play that make up a majority of the predictive power in terms of knowing what a coffee will taste like are color and development time. Color is simple enough; it's just how dark the beans are. Development time takes a bit of explaining though.
Green coffee is about 10% water or so. During roasting, this water evaporates into steam. Meanwhile, gases are also produced inside the coffee, namely, carbon dioxide. These gases can build up to incredibly high pressures within the bean. Eventually, the bean has to let out the gas and the way it does this is by rupturing. That rupturing makes a signature cracking sound we roasters call "first crack". First crack is a sign that the moisture has left the coffee. Water has a tendency to absorb heat, so until all the water is gone, the beans stay cool. Once all the moisture is gone, it means the coffee can finally begin browning. The time after first crack is what we call "development time".
Now during development time, there are some important chemical reactions going on. Namely, Maillard (pronounced "my-yard") reactions and caramelization reactions. Maillard reactions happen when carbohydrates (sugars) react with amino acids (the building blocks of proteins). These reactions cause a browning effect. They're the same reason bread turns brown in the oven. The second set of reactions is caramelization reactions. They break down sugars into more basic components, creating important flavors like toffee and caramel notes. It's important to know: these reactions happen quite fast. Within 15 seconds, a coffee can go from tasting fruity and sweet to chocolatey and toffee-like. Flavors snap in and out of existence at any moment, and it's the roaster's job to make coffee that is consistent batch-to-batch. This can be incredibly difficult and it's why here at Vezpa, we have to go to technical extremes to make sure our batches are perfectly consistent. That means following tight temperature curves and constantly checking the color of the beans to ensure they're exactly what we want.
Now, a roaster typically looks something like a steel rotating drum and some sort of heat source (ours is infrared, for the best temperature control and distribution). As the drum rotates, coffee is mixed and churned so that every bean has a uniform color. In the drum, there's a sample spoon that collects roasting coffee that we can pull out and check to see how the coffee is browning and seeing when exactly we need to remove the coffee from the roaster. The process is meticulous, but it has to be in order to make the most consistent coffee. Strict temperature curves are followed for batch-to-batch consistency.
The final result is a coffee that we spent hours perfecting. In just ten short minutes, green coffee is turned from something rather useless into something not only drinkable, but remarkably delicious. It's a process we take incredible pride in here at the Lab. Rest assured, the hands behind the brand are working hard to deliver you the best coffee possible. Always small-batch, always transparent, and always done with love and care. I sincerely hope you enjoy it.
Happy coffee drinking,
Luke