Welcome to Coffee Class, everybody. I am your under qualified adjunct professor. It's great to be here, and it’s great that you’re here too—unless you aren’t supposed to be, in which case, hey, no judgment. College is expensive.

Today, we’re covering the basics of how coffee roasting actually works. From soup to nuts—except, you know, there’s no soup… or nuts… just coffee. But we’ll be covering the broad strokes of the process, which will prepare you and your classmates for your education here at Ready Set Onlineversity, a prestigious institution known for its high academic standards and, uh… competitive tuition rates.

So first—coffee beans aren’t actually beans. Yeah, that’s right. We’re starting with a lie. First lesson: never trust anyone. They’re the seeds of a fruit called a coffee cherry, grown in places like Africa, South Asia, and South America. The process of getting them from the plant to your cup is long, complicated, and filled with enough jargon to make you question why you don’t just drink soda. Thankfully, you don’t—otherwise, you’d be reading SodaStream’s blog.

Now, let’s go over how these “beans” get processed. Pay attention, because there will be a test. Not from me—I’m not grading anything—but life will test you:

• Natural (Dry Processed) – Involves fermenting the entire coffee cherry, including the fruit and mucilage, on the coffee plant or in a container.

• Washed (Wet Processed) – Involves removing the outer pulp and mucilage from the coffee cherry, followed by fermentation of the beans in water.

• Honey (Pulped Natural) – A method where the outer skin of the coffee cherry is removed, but the sticky mucilage (pulp) is left on the beans during drying.

• Swiss Water Process – A decaffeination method. The Swiss Water process uses only water to remove 99.9% of the caffeine content from coffee.

• Wet-Hulled (Giling Basah) – Used only with Indonesian coffee, this rustic method was invented as a way to dry the green bean more quickly in a rainy, wet environment. Similar to the wet process.

This goes to show how early in the process flavor development begins. Where it’s grown, how it’s processed, who sneezed on it—everything matters. Places like Colombia, Ethiopia, Brazil, and Mexico all have different profiles and flair depending on soil, region, crop, and process, giving each final roast its own unique style.

At this point, enter the Roaster… let’s call him “Kiras.” Kiras weighs out the batch as the roaster heats up. Roasting coffee results in a weight loss of 14–23%, as internal gas pressure expands the beans by 30–100%. The beans turn a deep, rich brown, and their texture becomes porous and crumbly under pressure. The most important effect of roasting? The characteristic aroma of coffee, which arises from very complex chemical transformations within the bean. If you want to know more about those chemical transformations—take chemistry.

From there, Kiras keeps an eye on the temperature. Depending on the bean, he adjusts the heat to reach the desired roast. Some terms—which I’m sure everyone will be studying this week—are important to know while roasting:

• Charge/Charging – The process of preheating roasting equipment before inserting the green coffee. Turning on the oven, but fancy.

• Drop Temp – The point at which you release the green coffee into the charged roaster. Simple. Unless you miss it. Then it’s cleanup time.

• Dry End / Drying – When the temperature climbs towards 300°F. The beans go from green to a light yellow.

• First Crack – The second stage of roasting, where the temperature climbs past 300°F. The beans turn a light brown and make an audible “cracking” noise as they fissure and release vapor.

• Second Crack – Not all roasts reach a second crack. At this stage, the beans turn dark brown as a new wave of chemical reactions produces the ashy bitterness of very dark roasts.

• Chaff – A papery, flaky byproduct of roasting—like coffee dandruff. Often has a bitter, herby taste, like poor-quality green tea.

• Under-Developed – A bean or batch that was roasted too little. Typically identified by unpleasant “green” flavors like hay, herbs, and bitter nuts.

So, class, what have we learned?

Coffee is weird. Beans aren’t beans. Water can remove caffeine—but only if you know what you’re doing. And roasting is an art form… in a mad scientist kind of way.

Anyway, that’s it for today. Class dismissed. Now go apply this knowledge to real life… or just drink your coffee and pretend you know what you’re talking about. That’s what I do.