Closeup on Roasting Decaf Coffee

A side-by-side video guide to the color changes we see roasting decaf coffee versus non-decaf.

If you want to challenge your ability to roast coffee, try a batch of decaf. It’s quite likely the hardest coffee to roast for a whole host of reasons.

We get a lot of questions about how to best roast decaf coffee. I made this video to help represent the visual differences in a decaf roast and a non-decaf coffee side-by-side. This video doesn’t offer much in the way of roasting tips, but I feel it helps demonstrate what to look for when roasting decaf, and explains some of the “why” when it comes to roast differences.

My toaster-oven technique used to roast here is the best I know for demonstrating bean changes, because the coffee is stationary. I am not saying this is the best roast technique though. Without moving the coffee, it turns out uneven. (See my page dedicated to Convection Toaster Oven / Air Fryer coffee roasting for tips on how to get better results by this method).

Closeup on Roasting Decaf Coffee: Color Changes when Roasting Decaf

The coffees you see here are from Sweet Maria’s current stock (at this writing): Sumatra Wet Process Pantan Musara on the left and Sumatra Aceh Farmers SWP Decaf on the right (SWP= Swiss Water Process). The toaster oven used is the Cosori Air Fryer toaster oven I use in other videos

12 Responses

  1. Perfect timing. I just picked up my first decaf (the SM Moka Java blend) today and tried my first roast. Based on what I have become used to, it had a late first crack, and it didn’t have a ton of audible pops. Trying to judge visually was not helpful. I ended up kind of guessing when to pull it. Based on pre and post roast weight, it looks like the beans lost 15.12% of their weight. Some beans had horizontal cracks on the ends and others didn’t. Is there any guidelines for judging a roast level by weight loss? I tried searching the library and saw that anything more than 18% would indicate going past Full City, but couldnt find anything that might indicate City, City+, etc… Is it possible to judge a roast in this way, or are there too many other variables to make weight loss a helpful way of determining roast degree?

    Luckily, the decaf isn’t for me, so I won’t be the one to suffer if I messed it up. Just kidding… Kind of.

    1. Yes weight loss is tricky, depending on the roaster. 18% would be Full City in some roasters, but decaf actually tends to lose less total weight than non-decaf coffee, so 18% should be quite dark, I think. I would be interested to know if it tastes dark when you get to it. That blend is one of my favorite decafs we have received back from Swiss Water this year.

  2. This is really helpful! It mostly accords with my experience roasting decaf coffee (I typically roast both regular and decaf every week or two). I would say that in my experience decaf usually requires slightly less roast time, though I will have to try some of the adjustments to roast temp you suggest in the video. I typically roast with the same process I use for regular coffee (which is to bring the coffee up to 460 as quickly as possible in my Gene Cafe). I will try using a slightly slower/lower process!

    1. Yes we have found it can take less time in some roasters for sure. It makes sense in the Gene Cafe in particular. I hope a slightly gentler and slower roast works well. I think it might…

  3. I ended up brewing a cup in my Clever Dropped to give it a try. The weight loss was around 15%. I am still super new at this (and new to drinking coffee black), so rocks of salt, but if I had to guess, I would say it tastes medium-dark. I am not getting much fruit, but I have noticed the buttery sweetness mentioned in the cupping notes. I like it quite a bit, actually. Will have to do some further experimenting. I chose it because my stepfather and grandparents prefer decaf these days. My stepdad likes his coffee roasts on the lighter side and my grandparents on the darker, and this one seemed versatile enough to satisfy all of them. I may end up buying another bag or two for myself 🙂

  4. Well this is super informative and I now realize that I will have some challenges ahead of me.. I typically drink decaf because I enjoy the taste without the energy. I will be TRYING to do this in a nice Breville Air Fryer capable countertop oven which will make even more challenging it seems.

    My question is… Side by side the decaf looks much different and darker in color from the caf (That was the point of your video). With that said, am I still aiming for the darker color or should I pull back on the color for a lighter roast because it might have arrived at the desirable roast without the color we would normally see? I hope that makes sense.

    1. Hi Bill – decaf really looks darker to the eye that “regular” roasted to the same level. I have also found that in air roasters, in particular, it can need a little more heat to reach the same level of roast. I am usually increasing heat slightly and extending roast for 30 seconds to 1 minute with decafs it seems. They are tricky! The fact they don’t make a loud audible crack is really tough, since that audible cue really lets you know what’s going on. Decaf can leave me guessing at times.

    2. Thanks so much for the information @Owen… I appreciate the feedback.. So if I am still sorting out the process, the timing and the temp… Made a small 12 ounce batch this weekend and it looks and smells great but I suspect it is not as roasted as it needs to be.. It’s a little nerve racking to see it getting darker and darker and thinking that I am going to ruin it.. I did find that turning up the heat a bit was a good thing but I suspect that hitting it with too much heat right away is bad so I am going to keep with 375 – 390 to start and then getting to 400 a couple minutes in might produce some good results but we shall see.

      I found myself relying more on how it looked and cracked instead of the timer so I will have to dial things as I go. Might I ask what heat settings you use or would recommend if using an air fryer setup like mine?

      Thanks again..


  5. I’ve had a dickins of a time with my decaf.
    It DOES NOT expand?! I’m using a CAFEMASY
    Roaster where I can vary the time during the roast and baby my beans. I’ve tried with a bit of success to “par-roast” then take it out and let the half baked beans cool and rest, then I will put them back in the roaster to finish them. Sometimes I can get them to expand as normal but there are times I’m just stuck with under inflated medium to light roast. The flavor just doesn’t peak. Thanks for the video. At least I’m not alone.

    1. Hi Joan,

      Thanks for your comment. Hopefully the video confirmed that it’s not you! (or your roaster for that matter). Some of these differences in expansion, color, etc is just the nature of decaf coffee, and like you pointed out, the degree of these differences depends on the decaf. I generally try to slow the roast before hitting first crack in order to avoid having the roast get away from me. I also keep in mind when judging roast degree that the color will be a little darker than that of non-decaf so that I don’t wind up with an underdeveloped roast.

      Best of luck with your next decaf roast. Feel free to reach out with any questions!


  6. Hi, I use a Nostalgia air popper.
    I usually load 80g of fresh coffee, and since 1st crack (near 2min) I wait 1min30sec – i like light/medium roast.
    Using a decaf brazilian, what is your suggestion?

    Thanks in advance

    1. Hi Stefano,

      I’d recommend trying following your regular roast regimen for non-decaf first, and see where that gets you. The things to keep in mind are that decaf often presents darker because of the discoloration due to the decaf process, which can make judging surface color a little tricky. If it has a nice audible crack though, wait the 1:30 and see how it tastes. It might be a little darker than expected because decaf tends to roast a little faster (also a bi-product of decaffeination process). If you need to slow it down a little, try increasing the batch size to 100 grams.

      Hope that gets you close!


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