How I Roast Coffee Beans

I roast my own coffee beans. It’s fun, easy to do, and you’ll always impress your friends and company. Plus, you’ll have the freshest beans possible1. The downside is that once you try it, buying beans in a store will forever feel like you’re settling for second-rate.

Green Beans

Now before you can even start, you need to procure some green coffee beans. Some smaller coffee shops that roast their own beans may sell you green beans if you sweet-talk the owner. I’ve found green beans at specialty food stores, especially Italian ones. And, of course, there are numerous places to order green beans online. My favourite is OurCoffeeBarn.com2. They have a good variety of beans, good prices, and great customer service. (I live in Canada, but haven’t found a great Canadian source for green beans with both good selection and reasonable pricing.)

Unlike roasted coffee beans, green beans are very inert, and can sit for 6 months or more— as long as they are kept cool and dry— without losing freshness or spoiling. So ordering a larger quantity of green beans all at once will work out great for you3.

Roasting

The best way (i’ve found) to roast beans is in a hot-air popcorn popper4. These can be readily had at our local thrift store for a few dollars. Some hot-air poppers are better than others (you want one with as high a wattage heating element as possible). A Westbend Poppery II is ideal.

Here’s how I do it:

  1. Set the popcorn popper on a cookie sheet, under my range hood. Put a bowl in front of the popper to catch the chaff from the beans.

  2. Turn your range hood fan to the highest setting. During the latter stages of roasting, the roasting will generate quite a bit of smoke, which you want to exhaust outside of your house. (Some family members don’t seem to appreciate the smell. Go figure.)

  3. Put a ½ cup5 of green beans into the popper. Put the top “chute” part of the popper back on, including the butter-melting tray, if your popper has one. This all helps to keep the heat in the popper, raising the temperature enough to properly roast the beans.

  4. Turn on the popper. Pay attention to the beans as they roast. Look, listen, smell. The beans will go through several phases as they roast. First, they will expand and start to turn slightly brown. As they expand, the chaff (outer shell) will start to separate from the bean, and blow out the front of the popper. Hopefully you put a bowl there to catch it.

  5. About 3-4 minutes in, your beans will start to crack and pop— fairly loudly— as they roast. This is known as “first crack”.

  6. The beans will continue to roast and darken in colour. 1-2 minutes after first crack, the bean will go through a second crack, which is not as loud, and sounds more like Rice Krispies just after you add milk to them.

  7. After the second crack, the oils in the beans will start coming to the surface. This is what makes darker-roasted beans shiny. As the oils burn off, the beans will generate a good quantity of smoke. The longer you keep roasting, the darker the beans get, and the more smoke you create. I stop roasting just after the second crack, which is know as a “full city roast”.

  8. Turn off the popper, and immediately remove the beans from the popper. It’s important to cool them off quickly, to stop the roasting process. Some people just set the beans out on the counter in a pan— I pop mine into the fridge for 5 minutes. This is about the right amount of time so the beans have cooled, but are not so cold that they get condensation on them when removed from the fridge. Condensation is moisture, which is bad for fresh-roasted beans, especially if you then lock them in an air-tight container.

  9. When the beans are cool, store them in an air-tight container. I use glass mason jars (which I also get for next-to-nothing from the thrift store). Don’t store the roasted beans in a fridge or freezer. There is no point— it doesn’t keep them fresh any longer— and you risk getting moisture (condensation) on your beans every time you take them out.

  10. Let the beans rest for a day. The beans out-gas for about 24 hours after roasting, and will take on a more robust and full flavour after this time. But if you need coffee, there is no harm in using fresh beans right away. Try it at least once just for the experience.

I roast to different levels, depending on what variety of coffee i’m roasting, and the mood i’m in. Generally, I like a “full city roast”, which happens just after second crack.

Roast Levels

  • Light Roast is just at/after first crack.
  • Medium Roast is about 1-2 minutes after first crack, before second crack
  • Full City Roast is just after second crack
  • Vienna or Dark Roast is 1-2 minutes after second crack, when the oil is really burning off, and the flavour of the roast is fully developed.
  • French/Italian/Spanish roast is very dark, very oily.

I have had hot-air poppers which do not seem to get hot enough to properly roast beans. If you bought from a second-hand or thrift store, you have only wasted a few dollars, so go buy another one. Don’t give up!

Now that you have the freshest beans possible, you want to brew coffee from them in the best way possible. But that’s a story for another day.

  1. Even beans sold as “fresh roasted” in a store can be up to a week, or more, old. Make sure you know from whence your beans come. 

  2. No, i’m not affiliated, or getting a kick-back in any form 

  3. Caveat: I have sometimes purchased green beans which don’t seem to roast properly for some reason. Maybe they are very old, or stale, or who knows what. If you don’t have confidence or experience with your supplier, you may want to order a small quantity of beans the very first time. 

  4. There are lots of different options for roasting beans. You can use an oven, cast iron skillet, heat gun— anything that will heat up the beans to around 400-500℉. But each method has its pros and cons. A hot-air popper agitates the beans, which ensures a nice, even roast, and also serves to loosen the chaff (outer shell) and separate it from the bean. 

  5. You want an amount of beans that will allow them to agitate as the hot-air popper runs. This ensures an even roast. If you have too many beans, they will just sit there and the bottom beans will roast more than the top ones. If you have too few, they tend to fly out of the top of the popper as the roast. You may have to experiment to find the optimum amount for your popper.