Home Coffee Roasting Tutorial

I used to be a professional coffee roaster.  I had a beautiful, shiny roaster where I could roast about 15 lbs of coffee in under 30 minutes.  We roasted and sold hundreds of pounds of coffee from all over the world every week. I had artisan roasted coffee at my fingertips to supply myself with levels of caffeine needed to get through the day.  I was even considering patenting an intravenous solution for tired bloggers, mid-level managers and teachers everywhere.

But alas, no bountiful supply of freshly roasted beans await my waking moments.  No shiny workhorse to take the beans from grassy green to richly roasted perfection.

What's a girl to do?  Why roast coffee at home, that's what!

So let's start this caffeine rich adventure!  Dig out your hot air popper from the back of the cabinet and let's get roasting!

These are the things you need for roasting at home:

1.  Green (Unroasted coffee beans) available from any coffee importers.  Our favorite for home roasters is  Sweet Maria's.  Another importer is Theta Ridge. You might even find some at Amazon.  The main thing you want to check are the pounds available.  Most of the big importers (Cafe Imports, Royal Coffee, etc) don't sell "broken" bags, which means you have to buy those big 150 lbs bags of beans, which is not feasible for most home roasters.

2.  A hot air popcorn popper.  I have a Presto Hot Air Popcorn Popper.  

3.  A piece of metal screen.  I cut the metal screen from an old splatter screen that was broken.  The purpose for the screen is to keep the beans in and let the chaff out.

4.  A digital timer.

5.  2 Large cookie sheet sheets and a cookie cooling rack.  These are used for cooling the beans after roasting.

6.  Paper towels.

I roast outside because the roasting process produces a lot of smoke!  I can also just sweep my chaff and mess into the grass.

Step 1.  Set up all your supplies within reach.  The cord to the popper is probably very short, so take that into consideration when setting up your roasting station.

Step 2.  Measure the green beans into the 1/2 cup lid on the popper.  You don't want to overload the popper with too many beans.

Step 3.  Set the timer.  This will take some trial and error to get the beans to the roasting profile you like. The beans I have are Costa Rica Terrazu and we like them roasted light to medium (City Roast) to medium/dark (Full City Roast), which is right before 2nd crack.  This means that soon after the 1st crack, I am going to take them out.  I do not want them to reach the 2nd crack which would result in a darker roast.  For more information on 1st and 2nd crack, see Sweet Maria's Roasting Visual Guide.  I set the timer on 2:30.  (Two minutes, thirty seconds).  Because Popper roasting is not very controlled, I get a variety of "doneness" depending on which cycle of roasting I'm in.  If it's the very first roast, when the popper is starting from cold, the roast is lighter.  If it's my 4th cycle, the popper is still hot and the roast is darker.  You can modify your times so that all your roasts are alike, but I like the variety that each consecutive roast gives at 2:30.  

Step 4.  Pour the beans in the popper.  

Step 5.  Place the screen over the popper, then place the lid and the cup on top.

Step 6.  Plug in (or turn on) the popper and start the timer at the same time.

Step 7.  Wait and enjoy the roasting smell!  You will see the chaff blowing out of the popper.  The chaff is a thin skin on the bean that comes off when roasted.  I kept the popper here so you could see the chaff coming out.  After the picture I moved the popper so the chaff would go directly onto the deck where I could just sweep it off into the grass when I finished roasting.

Step 8.  When the timer goes off, immediately turn off the popper.  Carefully remove the (HOT) lid and screen.  Blow or wipe off with paper towels any chaff that is collected.  Dump the beans onto your cooling tray. You may want to direct a fan onto the cooling tray to help the beans cool down. A fan will also help extra chaff blow away. As with any cooking, even if the machine is turned off, the beans will continue to "cook" inside the popper and on the cooling tray, so get them cooled off as quickly as possible.

Step 9.  Agitate the beans on the tray to cool them as quickly as possible.  I also use a cooling tray under my cookie sheet to help circulate the air.

Step 10.  Remove chaff from beans and store in a container.  The beans will continue to let off gasses for about 3 days, so do not use an airtight container until after 3 days.  If you have a bag with a one way degassing valve, that is the best storage for newly roasted beans.

Step 11.  Repeat process for until you have as roasted as much coffee as you want.  I found with the Presto Popper, I can do 4 rounds and the machine needs a rest.  Remember, too, that green beans weigh more and have more volume than roasted beans, so you your beans will lose some weight in the roasting process.

Step 12.  Grind and brew as you like!  Our favorite way is coarsely ground and brewed in a french press.  Enjoy!

Disclaimer:  This information is basic information for a Home Roaster.  If you want to really get into the science of roasting, please visit Sweet Marias or the Specialty Coffee Association of America (SCAA).  There is also more information on Popper roasting at Air Pop Method.