Why?
Even though green coffee beans tend to be heavier due to the higher water content, generally it’s cheaper to roast your own compared to buying them pre-roasted.
You can roast the same beans at different levels to get some variety without having to go out and buy a new batch.
It’s kind of fun and a decent conversation topic.
Notes
Don’t be scared by how long this post is. It basically just comes down to spread beans on a cookie sheet, put in preheated oven, wait around 12-15 minutes and then take them out and cool them.
Since we’re talking about roasting beans, naturally you’re going to need a grinder to actually use them.
The process will create some smoke, even with a light roast. Basically, darker roast, more smoke. So far I’ve mainly done pretty light roasts and even though my kitchen doesn’t have much ventilation (and my oven doesn’t have fancy modern contraptions like, you know, a light or a fan) it hasn’t been an issue.
Your oven should be reasonably clean if you don’t want the roasted coffee to taste like random stuff.
If you’re a super coffee snob and it has to be perfect, this may not be for you. It’s pretty easy, but odds are the first few tries aren’t going to be perfect especially if you like darker roasts.
You’re going to want something like a large metal mixing bowl and colander for the cooling process. My colander is plastic, so you can probably get away with that if you don’t put the red hot beans in it directly out of the oven.
You’ll also probably need access to an outside area where bits of coffee chaff blowing around aren’t going to bother people. I don’t think there’s really an easy way to deal with coffee chaff indoors.
By the way, don’t try to grind green coffee beans in a normal grinder. They are insanely, and I mean insanely hard and tough. You’ll destroy your grinder unless it is an absolute tank. (I’d say it’s also not really worth trying, green coffee didn’t taste very good to me.)
How
Here’s the process:
- Start preheating your oven to 500f/260c. (Some people say as hot as possible, some people use a slightly lower temperature like 460-475f.)
- Get a cookie sheet ready. Just a standard cookie sheet. Mine aren’t super clean so I put a layer of silver foil on it. Don’t preheat the cookie sheet itself.
- Measure out about 1 cup of green coffee beans. (I’ve found you can fit about 2 cups on a single sheet but it’s probably better to start small.) You want to make sure the beans are spread out evenly in a single layer.
- Look for beans that are discolored/damaged and toss them away. Don’t be a perfectionist though, just get rid of 10-15 of the worst looking beans. Something like that.
- Place the cookie sheet in the oven once it’s reached the correct temperature. I put mine on the bottom rack near the (electric) heating element. If you’re going for a darker roast, I guess this might make burning them more likely.
- Set a timer for ~12 minutes. I wouldn’t recommend roasting longer than 14 minutes your first time.
- Now you wait a bit. Probably around the 8 minute mark, you’re going to start hearing sharp cracking/popping sounds. Don’t worry, the beans won’t jump around like popcorn and the sound is fairly loud so you’re not likely to miss it. At this point (or in 1-2 minutes) you can remove the beans and have a light roast. This point is known as the “first crack”.
- After a couple of minutes, the sounds will die off and you won’t hear anything for a little bit. If you keep roasting, you’ll start to hear a softer, more muted crackling sound start. This is the “second crack”. I would not recommend roasting past this point until you’re comfortable with the process and have an idea of how roasted the beans are at this point. If you roast much longer, it’s very easy to burn them and there’s also going to be a lot more smoke.
- Remove the beans from the oven. You can let them rest for 1-2 minutes on the cookie sheet if you want, then transfer to something like a metal mixing bowl. It has to be something that can deal with 500f stuff touching its surface.
- Ideally get another mixing bowl/colander/whatever as well. Pouring the beans back and forth through the air is a good way to cool them off and remove chaff. What’s chaff you ask? The beans are coated with a papery layer of chaff. Don’t worry though, once they’re roasted it’s really easy to remove. You want to try to cool off the beans pretty quickly at this point.
- Go outside and blow gently on the roasted beans in your bowl. You should see a bunch of super light, papery chaff fly out. You can pour the hot beans from one bowl to another, and if there’s a bit of a breeze that’ll help a lot. Otherwise, you can just blow on them. You could also stir them around with a wooden spoon or something to encourage the chaff to separate.
- Once the chaff is mostly gone (it’s fine if there’s a little left, or little pieces stuck to some beans) and the beans are fairly cool you can just leave them in a safe place for around 12 hours to fully cool and vent CO2. Don’t put them in a sealed container for the first 12-ish hours.
Conclusion
One thing to note is you don’t want to actually grind/use the beans for at least 12 hours. It might seem unintuitive, but from what I’ve read as freshly roasted as possible isn’t necessarily best. Depending on the beans/roast level, the coffee might reach its optimal tastiness even a couple weeks after roasting.
I’m far from an expert, but feel free to ask questions in the comments if you want. I can recommend a grinder/beans to get started with if anyone needs information like that.
When I was a kid, every afternoon my neighbor (an old lady) would sand-roast some coffee beans in a big wok on a wood stove. The smell of the roasted coffee would fill the entire neighborhood. My dad would often send me to buy some of those coffee for like 50 cents. She would make a cone out of a newspaper sheet and put a big scoop of freshly ground coffee there. Oh, and she ground the coffee using a big stone mortar. I’m pretty sure the beans were from her backyard too because her backyard was full of coffee trees. This was in a small village in Sumatra btw.
The problem with roasting your own coffee is that you don’t have the equipment to control temperature and time precise enough to make sure that no acrylamid or furan is created. Both of those substances are carcinogenic and should be avoided. If you buy roasted coffee it’s always made sure that it is not containing that stuff.
Thanks for this post. I’ve been roasting during covid as I couldn’t find proper roasted beans, but never knew it could be carcinogenic. I’ve reverted back to roasted beans as it was just too time consuming and inconsistent, even with a cheap coffee roaster.
Because coffee beans have a flat side, this method will produce an uneven roast. The way I was taught was to use a pan and to stir consistently. You’ll still end up with a non-uniform roast, but it should be a bit better then oven roasted.
Cast iron works well because of heat retention and radiative sides. Plus they work great on a grill so all the smoke and chaff stays outside. (My wife doesn’t let me roast inside anymore)
But at the end of the day it’s not too important how you roast them, just that you are home roasting and enjoying your morning brew.
I recently got into home roasting and it’s been awesome. I have a bio light that runs on wood, and I just knocked down a couple trees on my property, so infinite free heat source that I can use outdoors. I also prefer a bit of an uneven roast as well cause it gives you a bit of a black and tan flavor.
Because coffee beans have a flat side, this method will produce an uneven roast.
Interestingly, when I was researching this I saw some people say they actually referred that for the variety or making the coffee taste more interesting (broader range of flavors getting combined). Not sure I’m enough of a gourmet to really tell the difference, or have a problem with it even if I could. I’d guess it’s about the same as just mixing two different roast levels unless you do something that actually hurts the quality like burning some beans.
The way I was taught was to use a pan and to stir consistently.
I might try it eventually. I’m super lazy, so just tossing them into the oven and leaving them there is a lot less work than standing at the stove stirring the beans.
I have a grill and air fryer with a rotisserie. Both have basket attachments. Would these work?
The air fryer definitely should work (make sure the basket is too small for beans to slip through). I haven’t used that method myself so I can’t really give you advice, and I’d guess it’s reasonably noisy so it might be a bit difficult to hear when the cracks occur (especially the second one which is fairly quiet).
If the grill can get hot enough, that should also work fine. You can even use a frying pan and stove top, so really anything that gets the beans to the correct temperature and ideally can stir them for even roasting is going to work — though the times and such might vary. I’ve only used the oven so far.
You should be able to web search for more specific instructions for any of those methods. If you can’t find what you need, let me know and I’ll try to search as well.
Yeah that’s basically a drum roaster so sounds perfect!
The problem with roasting your own coffee is I have a life in a city in the Western hemisphere and nowhere around me sells raw coffee beans.
You probably also don’t value your time using pennies or fractions thereof on an hourly basis.
I have no problem with people who enjoy roasting their own beans. The process is fascinating. But when I’m partitioning out my 24 allocated hours in a day, roasting beans makes neither the list of preferred recreational activities nor the top 10 money making (or saving) exercises.
The problem with roasting your own coffee is I have a life in a city in the Western hemisphere and nowhere around me sells raw coffee beans.
Does “Western hemisphere” mean the US? If so, it’s no problem getting them. Just for example, this is what I have currently: https://www.amazon.com/gp/product/B01GGMF8RA/ (not a referral link or anything)
https://www.freshroastedcoffee.com/ also sells green coffee beans. Those are ones I’ve bought from previously without issues. If you live in a different country then it might be harder but it’s almost certain that there will be online stores in your country that sell green coffee beans. You might even be able to find local stuff.
I’m all for cooking at home and lots of DIY projects, but I just think this is one thing better left to the pros. Also, yeah I’m in Canada. So I’m sure there are online options, but again, time and equipment are huge factors.
Also, yeah I’m in Canada. So I’m sure there are online options
100%. If you wanted them, you’d have no problem.
time and equipment are huge factors.
I mean, the equipment is an oven, a cookie sheet and a heat resistant bowl or two. Nothing exotic.
The time is about what it takes to make a simple pasta dish or stir fry. It seems weird to me stressing about the time when it’s about the same as preparing a simple meal and only has to be done once every week or so.
Obviously not trying to pressure you to roast your own coffee if you don’t want to, it’s 100% up to you. I guess I feel like you have to be greatly overestimating the time and effort to say something like that.
It seems weird to me stressing about the time when it’s about the same as preparing a simple meal and only has to be done once every week or so.
Yeah, I already have to do the work to prepare meals everyday to eat. Adding that on is just more work.
It’s awesome if you want to do your own as a hobby, but my time doing that every week is going to cost more than buying a pre-roasted bag.
It’s awesome if you want to do your own as a hobby, but my time doing that every week is going to cost more than buying a pre-roasted bag.
If you think that way then why are you preparing meals every day to eat instead of just buying them pre-made? Do you consider preparing those meals your hobby?
I could just as well have created a post here aimed at people who had never made their own food like “You should know it’s actually really easy to prepare some simple meals like stir fries or pasta”. Who would say “My hobby is knowing how to cook pasta and throw some sauce on it to make a meal” though? Or say to the person “It’s awesome if you want to cook pasta and heat up sauce to serve on it as a hobby, but I’m not into it myself”. Guess it seems weird to me because you’re talking about it like it’s a defining characteristic that a person would be pretty invested in rather than an approach to dealing with something that could have some advantages. (Arguing with random people on the internet though? I think that’s something we can safely call one of my hobbies.)
You’re comparing a need (food) to not even a want, but a possibly nice to have (self-roasted coffee).
A person can’t live without food. However, a person could live without coffee. I can definitely live without roasting my own beans once a week and using that time saved to do something else.
You’re comparing a need (food) to not even a want,
This makes no sense. We’re talking about preparing it yourself vs buying it. In either case, you get the item so there’s no “this need doesn’t get satisfied” possibility.
You don’t need to roast your own coffee, just as you don’t need to preparing your own meals: instead of spending the time personally preparing to those things, you could buy them. So if your position is “my time is so valuable that I’d rather pay someone else to do the work”, then why is that only applied to roasting coffee and not preparing meals?
One day I will try this because I love coffee and I like experimenting in the kitchen in general, but the reality is the time and effort required would not outweigh the cost, quality and consistency of a local roaster who can get coffee out to you a couple of days (at most) post roasting especially if I factor in the multiple cups a day I drink!
You should also know that you will set off every fire alarm in your house
This is how i started out, but a good old fashioned hand cranked pop corn popper on the stove for roasting up to a 1/2 lb. of green coffee is the best.
For me roasting your own beans is a case of “easy to do, difficult to master”. It’s a great hobby dont get me wrong, but the way this post is phrased makes it seem like you’ll be getting amazing results from the get go.
There’s a huge amount of trial and error and even with the best will in the world you might not be able to come close to what a local roaster can provide.
