Coffee Roasting Basics – Color Changes

Coffee Roasting Basics – Color Changes


So I wanted to show you very quickly what happens to coffee as it’s roasted. This is green coffee Coffee is the seed from the fruit of a flowering tree and it’s dried…it’s processed and dried…out of the skin and it becomes this very dense, green bean. It’s not really a bean, it’s a seed… but we’ll call it a bean, because everyone does. As you start to roast the coffee, it goes from that, to a slightly pale, white color. What’s on the outside here, is Chaff, it’s also called silver-skin. and it comes off during roasting and the next stage… So it’s turning pale at about 2 to 3 minutes into roasting. Some roasters a little bit faster, in an air roaster, now we have kind of a tan or orange stage, where it’s definitely losing some heat, losing some moisture content, The coffee is becoming a little bit lighter, moves around a little quicker in the roaster… And this is the tan stage, this is very slow, this early development, From the green to the tan…you know, in some roasters that could be ten minutes of development until you hit first crack, so it’s still quite a light colored coffee, not what you’d want to drink It would taste very grain-y if you drank it. Now here we’re approaching first crack, which, like i said, could happen anywhere from, in a real fast roaster, several minutes… in a drum roaster, maybe as long as 10 or 12 minutes. And you see this very highly varied surface texture, and this pale silver-skin, chaff in there… Now here’s where we’ve actually gotten into coffee that could be considered…you could drink this coffee. This coffee has gone through first crack, so there’s been this audible, popping sound In the roaster, and that’s kind of your clue. Once that finishes…the popping… That coffee has gone through first crack, we call this City Roast. It’s a lighter roast, and looking under the strong light you see all that dark surface texture in it, but this could be a very good roast for coffee that you want to be a bright, lively cup. This is a little bit more roast, but you notice that this bean has puffed up a little bit more it’s opened up that crease, it’s not quite so flat on this side. The silver-skin is a little darker. So that’s a City Plus Roast. We’d call this one a City plus, too. Now these last stages since I started showing you the brown coffee, these are pulled at 30 second increments or less, so in the first part of the roast, from green to yellow, things happen really slow. and then it’s quite a fast process so you really have to be there watching the coffee. This is an excellent roast right here, a great roast level to not get that charred taste, but have a really sweet and refined cup. That’s a City Plus Roast. Now here’s a Full City roast. We’re right on the verge of getting into Second Crack here, which tells you the coffee’s getting into dark roast territory. Notice it’s more puffed up, and the chaff layer in here has changed color. It’s a dark color now. Now if you like Starbucks, this is what you like. This coffee has gone fully through the Second Crack, And in fact, it’s so explosive, this crack, that it’s releasing carbon dioxide that’s formed during roasting, within the bean, It’s actually blown off a piece of the bean right here. And then finally, we’re at a VERY dark roast, now, This is very fresh coffee, I roasted this, actually less than an hour ago, But you can already see some oils starting to develop on the surface there. All of those last three roasts I’ve shown you, if you left them for 3 days they’d have oils on them. And, in fact, you know, if you leave them for months, they’d be glazed in oil and that’s what old coffee looks like when it’s Dark Roasted. So that is, briefly, the changes in color during Coffee Roasting.

70 thoughts on “Coffee Roasting Basics – Color Changes”

  1. @yt6 no – we mean air popcorn poppers like the west bend poppery, or home roasters like the freshroast or the hearthware i-roast

  2. @tdjtx I use the WestBend Poppery too. I'm getting ready to try and automate the process with a microcontroller. We'll see how it goes.

  3. @tdjtx Basically it's a very small computer. I'm tired of having to watch and dump and refill the popper. I'm going to automate it.

  4. I thank you especially for taking the time to partially roast each phase. Thanks again for posting. CNN just announced a rise in coffee prices…time to start growing…

  5. i've always found it difficult to understand the difference between dark roast and strong roast… can anyone explain?

  6. Yes, I agree, partly also because some french roasts and espresso roasts can be very very close to being burnt if I understand? Definitely past the last stage shown in this video?

  7. I doubt if strongly brewed coffee is carcinogenic!? Do you have any proof to what you are implying?

  8. Acrylamide is delicious, Maillard reactions mean flavor, Do I have to go all Braveheart and say that every man dies, not every man truly lives.

  9. the basics of coffee roasting is so important. but then brewing the coffee is so important as well. many ways to mess it up if not handled properly.

  10. So if I want a rule of thumb for home roasting green coffee beans for a less acidic, less bitter, smooth what stage should I stop at. Many of the vids I've seen stop at 2nd crack. I don't want a real dark roast as I've been told that the beans are going to produce a bitter tasting product.

    Thanks for the vids….

  11. It's best to experiment and find what's best since different coffees react differently to roasting but in general, acidic, bitter flavors are usually found in lighter roasts. Bitterness can also be found in roasts that are too dark where you will tend to taste chalky, charcoal flavors.

  12. Glad I saw this one. Like a Starbucks roast that was mentioned at 3:30, one of my recent roasts (in a popcorn popper) went well into 2nd-crack and several of those 'explosive', crater like divots were created. I hadn't seen those before on any roasts I'd purchased in my many years of coffee consumption; I thought it was either something funky with the batch of beans or more likely the case, too fast of an overall roast. That said, it tasted far better than any Starbucks I'd ever had!

  13. This is a perfect little source of information for beginners, thank you for providing it.  Husband and I have been stove top roasting with a small Indian wok, a karhai, and an all-steel lid with drilled holes.  Stove is gas. Wok has steel handles which allows for an oak dowel or wood strip to run thru the wok handles and lid handle.  The wood serves to keep the lid in place so the wok can be shaken up and down vigorously and serves to keep the hands comfortably away from the heat.  Wok is about 7.5" size and can handle a 1/2 cup of green beans at a time.  Cost of wok was under $10.  This set up isn't for someone wanting to roast a pound at a time but still the beans come out perfectly even and we haven't had a single bad roast.

  14. @1timby; I like the same roasts that you do and I've found different beans create very different flavors. Sumatra is one of my favorites because it has low acidity to begin with. Colombian is also very good when roasted to medium. I also only brew my coffee using the pour-over method which is basically the manual version of a drip. No bitterness at all, just smooth delicious coffee right down to the bottom of the pot. I use both the Chemex brewer and the Hario drip brewer for single cups. Hope this helps.

  15. It's important to learn the basic of coffee roasting. Thanks for sharing this video. Gonna share this to my coffee-lover friends.

  16. I'm sorry, but why on earth is it city roast, city + roast, city +2 roast, and full city roast? Seems a little repetitive.

  17. I have an air popcorn popper but don't have coffee beans, I used lentils instead and it worked just as well, tasted just as good as the coffee in the McDonalds drive thru

  18. Interesting! Thanks for allowing us to see the stages.

    I would of liked to also see what an "over-roasted" or burnt bean would look like.

    I just tried roasting some Brazilian green beans and my first batch was successful. I got a nice dark roast and it tasted awesomely great! I cooked mine on an iron skillet outdoors, and my first batch was just a quarter of a pound.

    Then I got over zealous. I decided to try and roast three quarters of a pound using the same roasting method as before. To my dismay the batch was unevenly roasted and I ended up with a light to medium roast. It was under roasted and the taste of it is almost nut-like in flavor. Even the drip coffee maker dispensed a very light brew.

    There's so much to learn!

  19. Thanks very good video and nicely informative. Have you ever tried Doi Chaang cofee from the mountainous jungles of NW Thailand? I live in Thailand and it is awesome, smooth, lovely coffee

  20. Every varietal is different. For instance, Sumatras appear much darker for the same level of roast. At first crack they already look like other varietals at full city. The level of the roast is measured more by the temperature and relativity to the "cracks" than by color. Also, some varietals have all their forward flavors released in very light roasts, and others build their flavors as they get farther along in the roast. For every varietal you want to find the "sweet spot" where its own character is more developed. Don't assume, "darker is better or less acidic," because with many varietals all the distinct aromas will go out the exhaust vent instead of into the cup if you go darker. Everything this guy is saying applies only to the specific varietal he's showing in the video, and I didn't hear him identify what kind of coffee bean he's playing with here.

  21. Are the bean's color relatively similar with their temperature while roasting?

    For example when the coffee bean temperature is at 433 F (222.5 C) it becomes medium or medium dark ?

  22. When I hear terms like 1st crack and such, my mind wanders back to my grandmother making peanut brittle and candies because she used terms like soft ball and hard crack to describe the phases of sugar as it cooks.

  23. The beans in this demonstration are Arabica beans, yes? Are the timings the same with Robusta beans, or shorter because the beans are smaller?

  24. BS….simple science of coffee roasting must measure for 11% moisture content. What this video show is bad coffee beans coming from poor field processing.

  25. thank you sir. I love coffee and I want to create a small coffee shop, but I do not have enough experience in the field. So I ask you to help as much as possible in how and how to roast the coffee and what features are added during roasting to get a great taste. I also thank you for all the information and thank you

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