Roasting Coffee in a Popcorn Popper

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The conversation always starts the same. While sharing some freshly brewed coffee with a neighbor or co-worker, the topic of roasting coffee at home comes up. Most have no knowledge on the topic and they ask how it's done. At which point I start listing off the various methods of home coffee roasting.

Recently I was stopped in mid sentence as I began a high level overview of the various roasting methods. The interested party looked at me and asked point blank to tell him EXACTLY how I roasted the coffee he was enjoying. There are many different variations for roasting coffee in a popcorn popper, but in this article I'm going to describe EXACTLY the steps I use for my favorite method of home coffee roasting - the original West Bend Poppery.

West Bend - The Poppery
The West Bend Poppery. Excellent for home roasting coffee.

What I Use

  • 1500 Watt West Bend Poppery (no substitutions)
  • empty soup can or fitted dryer vent
  • wooden spoon with a long handle
  • Salter kitchen scale (I roast by weight, not volume)
  • 2 metal colanders
  • plastic tupperware bottom
  • green coffee beans (use your favorite search engine to find them)
  • package of Post-It notes
  • black marker
  • air-tight container
  • broom or Black and Decker DustBuster

1500 Watts
Underneath the West Bend Poppery there is a plate that shows the wattage. Look for 1500 watts.

Roasting Preparations

Roasting coffee in a popcorn popper is not an indoor endeavor. Without modifications, you would fill your home with smoke. The first step is to find a spot outside near an outlet. It will produce smoke, so keep it away from open windows. If your popper has one of those plastic lids, remove it and set it aside. The next thing you need to do is prep the soup can. Open both ends of the can and clean it. You'll be using the can as a chimney, so make sure it can fit snuggly into the top of the popper.

Why use the West Bend Poppery?

There are several popcorn poppers which will do a good job roasting coffee. In my opinion, the best one is the orginal 1500 Watt West Bend Poppery. This is not the same roaster as the West Bend Poppery 2, which was smaller and had less wattage. The only way to acquire an orginal Poppery is through eBay or yard sales. At one point I owned 5 of them, and paid an average of $40 per unit. As a popcorn popper that's too expensive, but as a coffee roaster it's a bargain. The West Bend Popperys are built like tanks. I've never had a single failure.

Note that when buying a West Bend Poppery through the mail, it's possible that if the unit was poorly packed the front lip could be snapped off. This is not a major concern, since the lid is not used. Using a product called Gorilla Glue will restore your unit.

Reasons to NOT use the West Bend Poppery

As much as I prefer the West Bend Poppery for most of my roasting, there are real reasons on why this may not be the roaster for you. The first reason is it is an outdoor roaster which doesn't like colder weather. When I say that it doesn't like colder weather, I'm mostly referring to the first roast. On cold days the first roast can take an extra 3-4 minutes. The result is the beans sound done (well into the 2nd crack), but visually they look light. The taste is a little flat. Subsequent roasts tend to roast quicker and taste better. There are cold weather tricks, however my advice is for beginners to learn the Poppery during nice weather. During the winter, even I put my Poppery away and use a counter-top roaster.

Step By Step Roasting

Turn on the machine. As you are preparing the roast, it's a good thing to get the machine warmed up.

Measure out the beans. Place the Tupperware bottom on your kitchen scale and zero out the reading. From here you will place between 100 - 150 grams of green coffee in the Tupperware. How much coffee you use depends upon two things: the size of the bean and type of home roaster you are. Use the following chart to calculate the bean weight.

Bean SizeHands Off RoasterHands On Roaster
Big (Nicaragua "elephant bean")100-105 grams110-115 grams
Normal (90% of beans)120-130 grams125-135 grams
Small (Peaberries)130-135 grams140-150 grams

It should be noted that there is technically no such thing as hands off coffee roasting. Roasting coffee in a popcorn popper does require constant attention. Hands off in the above chart refers to the amount of work you need to produce excellent coffee. In short, more coffee equals more work. Leaving a roast unattended is never a good idea.

Weight coffee beans
Use a kitchen scale to weigh the green coffee beans.

Pour the beans slowly into the popper. When beans first go into a popper, you can observe three possible behaviors.

  1. The beans spin in a circle. This means you can probably add a little more coffee to the roast. Failure to add more can result in more initial air flow and extend the roast time. Extending the roast too long will bake the beans and yield a flat taste.
  2. The beans dance in a random pattern. You placed a perfect amount in the popper.
  3. The beans aren't moving. For a hand-off roaster, this means you added too much coffee. For a hands-on roaster, this means it's your job to keep the beans moving during the first few minutes of the roast. Using your wooden spoon, stir the beans for 5 seconds every 15 seconds. Gradually the beans will get lighter due the roasting process and they will be able to move on their own. Until that time, your goal is keep beans from getting stuck touching the popper heating element. Beans can burn in less than a minute.

Based upon the above behaviors, I advise those new to popper roasting to use fewer beans. As you gradually gain experience and confidence you can add more beans. I once did 160 grams of a Colombian Peaberry without burning any beans.

The video above shows approximately how full the popper will be at the start of a "hands off" roast.

Although stirring is required when overfilling the popper, I always stir to release the chaff. When coffee roasts the skin from the bean comes off. This skin is called chaff. Before the roast is finished, the chaff needs to be removed. It can be removed during the roast or after the roast. It's easier to do during the roast. Once the chaff starts to come off, using the wooden spoon you can agitate the beans to release the chaff, which will come out the top of the popper. It should be noted that decaf beans do not have chaff and roast faster.

As the beans roast, they will get lighter. As they get lighter and start jumping, some could jump out of the popper. To prevent this possibility, place your open ended soup can into the top of the roaster. This will keep all the beans in the roaster.

Now that the beans are roasting, our next step is determining when to stop the roast. There are two common methods to roasting. One is by sight and one is by sound. Experienced home roasters typically roast with both, with sound being more important. New home roasters favor sight. Determing the sweet spot to stop a particular roast is a never-ending process, so it won't be covered in this article. However, I can advise begineers to use beans that taste good when lightly or darly roasted. Beans that I feel taste good at different degrees of roasting are Colombian, Guatemalan and Sumatran. Don't practice with island beans or those that are less forgiving to being over-roasted like most Africian varietals.

Coffee Roast Progress 1

Coffee Roast Progress 2

Coffee Roast Progress 3

Coffee Roast Progress 4

The four photos above show a roast color progression.

In this video, you can hear the start of the 2nd crack. At this point, I usually stop the roast.

Stopping The Roast

Hit the off switch on the popper. Using the wooden spoon, gently knock the soup can chimney off the popper. You don't want to grab the soup can, as it is very hot. Pour the beans into one of your two metal colanders. You goal now is to --quickly-- bring the coffee down to room temperature. Failure to do so will cause the beans to continue roasting, which could lead to over-roasting and burning. On most days, simply pouring the coffee from one colander to another for a few minutes is enough. I try to face any wind to accelerate this cooling. On hot days with no airflow, you may wish to use the water bottle method.

cool coffee
Move the coffee back and forth between the 2 colanders to quickly cool the beans.

After the beans have cooled, they should be stored properly in an airtight container. Don't put them in the freezer and definitely keep them out of the refrigerator. Keep your container at room temperature. Take out a Post-It note and write the name of the bean and the date you roasted it. Most beans will start to lose flavor after 7-10 days. That note is our reminder to throw those beans away if they get too old. If you find yourself throwing too much away, roast less. Typically I roast twice a week, so I can keep the average age of my beans between 2-3 days.

Post-It Note
Adding a dated Post-It note to your coffee storage container is a good habit to develop.

Clean Up

Roasting coffee in a popcorn popper will produce chaff. Right now you've probably got a mess of chaff around your popper. Some beans produce a lot of chaff (Brazil), whereas decaf has none. At this point grab your broom or DustBuster and clean it up. I usually let my popper cool for a few minutes before storing.

Ready To Drink?

With the exception of decaf, coffee is not ready to drink immediately after roasting. There needs to be a period of degassing and that period will vary from bean to bean. Some beans require more time to settle than others. Although each bean is unique, here are some general guidelines I use when roasting with a West Bend Poppery. Note that the recommendations below are not for peak time, but for earliest time to drink.

Bean TypeWait Before Brewing
Latin America (except Costa Rica)8-24 hours
Costa Rica1-2 days
African2 days
Most Indonesian2 days
Aged Sumatra or Indian2-3 days
Espresso Blends1-3 days (depends)
Island2 days
Decaf0 hours

Advanced Topics

Advanced topics such as hardware modification or indoor ventilation are not covered in this article. The Poppery can be modified to perform it's own cooling. I have a modified unit, however I prefer to cool beans by hand. While one batch is cooling, I'm roasting a second. And since I live in Southern California, I have little reason to roast inside most of the year.

Conclusion

Roasting coffee at home is highly rewarding. One of the benefits of learning to roast with a West Bend Poppery is that unlike many of today's counter top roasters, which are extremely loud, this roaster allows you to hear the roast. It's quiet nature puts your auditory focus on the roast and not the engine doing the roast. And finally, the Poppery allows the home roaster to make some delicious coffee for a very little initial investment.

Resources

Roast Your Own - Our original popper article uses the Poppery 2, but the rules are basically the same.
Why Home Roast? - In the event you didn't know.
Popper Roasting Tips - Some tips that apply to popcorn popper roasting in general.
Winter Home Roasting - A method to prevent under-roasting coffee in cold weather environments.

Published: May 2004, Last Modified: February 2013, Author Google+