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Hi Everyone,
Kristin is already starting to wrap up her culinary educational experience at PICA, and with her recent time focused on studying for finals and such, she asked if I’d be willing to do a guest blog entry about my recent coffee roasting experiences with a modified popcorn popper. I can see the relation to culinary arts, and she describes it as ‘the best smelling hobby you’ve ever taken up’!
I’ve been spending some personal time lately on roasting coffee at home, largely out of necessity (we’re spoiled with an abundance of good coffee in Portland), but I’ve also developed a strong interest with the process. It’s a very interesting mix of science and art, almost like alchemy if anything else.
There are a number of excellent coffee roasters in Portland, our favorites being Stumptown Coffee Roasters (who just opened a roaster and coffee shop in NYC) , and Ristretto Roasters. Portland has a long history of both local artisan and major roasters, and Kristin and I have both progressively become more picky about our coffee tastes. Since moving to Vancouver, we’ve been bringing coffee back from Portland for home brewing, but miss the local coffee houses serving up excellent locally roasted coffees. In all fairness, I’ve found JJ Bean to be a decent roaster in Vancouver, as well as 49th Parallel, who roasts for a number of smaller coffee shops including the close to our house Elysian, and the local chain Cafe Artisiano; both brew some of best coffee we’ve found so far in Vancouver.
This write-up is intended to be an overview of the complete process of roasting and preparing coffee, from green bean to cup. Many of these tricks and techniques I’ve learned from spending time in various coffee houses in Portland, excellent websites such as Sweet Maria’s, and specifically fellow Portlander coffee-geek David Turnbull. It will provide a quick overview of the coffee roasting process with a modified popcorn popper, and then the method of how we prepare our coffee at home which we’ve found to provide the best tasting cup.
Supplies
Here are the basic supplies needed:
- Modified popcorn popper
- Supply of green coffee beans
- A good burr coffee grinder (not a blade grinder, which just suck)
- Chemex, french press, or your preferred method for coffee making
- Measuring cups, bowls, and colander

Roasting Coffee At Home with an Modified Popcorn Popper
Popcorn poppers make great cheap coffee roasters, but they need to be slightly modified in order to let them get hot enough, and provide some control over the airflow which essentially allows you to develop a roast profile for the bean you are working with. I’m not going to go into a lot of details about the modification process itself, as there are a number of excellent references already on the web which describe that; they can be found in the links at the bottom of the page.
As for acquiring a popper, 2nd hand stores such as The Salvation Army, Goodwill, etc.. are great sources, as are eBay. The main thing to look for in finding a suitable popper, is finding one with the proper metal air cylinder. My mom donated her 15yr old ‘Toastess’ popper, which seems to be a popular brand in Canada and works well. The basic modifications which need to be performed are:
- Bypassing the thermostat so the popper can get hot enough (may also need to bypass the thermal fuse)
- Getting some control over the fan, which controls airflow
- Installing a thermometer so you can monitor the temperature during the roasting process
Once you have modified a popper which can be used for roasting coffee, you will need to acquire some unroasted green coffee beans. Availability of green beans varies with your location, but here are some ideas:
- Some Whole Foods markets in the US carry grean beans, although not here in Canada.
- Online – specifically Sweet Maria’s has a well-priced and excellent selection, along with some great notes about the bean and ideal roasts.
- A local roaster will often sell you small quantities of green beans if you ask. I found JJ Bean in Vancouver (only the main location on Powell) sold whatever they were roasting at the time, and my Mom in Lethbridge also found some at a local roaster.
Green beans typically weigh 1.25-1.5 times as much as when they are roasted, and on average cost 1/2 to 1/3 of the roasted prices. There are so many variances in coffee beans including wet processed vs. dry processed, shade grown, organic, the region, etc.. that I’m not even going to bother getting into it, but that’s what makes this hobby to interesting. Just keep experimenting with beans and roast profiles as you develop your tastes and preferences.
Here’s a picture of my setup, ready to go:

The control box to the popper turns the heating element on/off, and the dimmer controls the fan speed. The glass bowl is there to collect the chaff, which is the inner-most skin of the bean that comes off during the magical roasting process. You can also see my measured out green beans, which vary by popper but I find 1/3rd cup works best in my popper. The best way to tell the correct amount is by putting in enough coffee with the fan on nearly full, and the green beans should just barely be moving.
Here are some additional images showing the coffee in the popper, and with the hood on which is used to hold the thermometer:


Once the correct amount of coffee is in the popper and the fan is moving, turn on the heater to start the roasting process; this is where the interesting part begins.
You will want to carefully monitor the duration of time and temperature of the roaster; I use the stopwatch feature in my iPhone. You can do this without a thermometer, but carefully watch the time and color of the beans and keep a log.
The time/temperature ratio of each roast is essentially the ‘roast profile’, and will have a major impact on the final roasted product. Ideally, the roast should be 6-12 minutes at least; anything shorter will just taste like burning. The style of the roast is the interesting part of the hobby for me, as different coffee’s will exhibit different characteristics based on their origin, and how they are roasted. In general, the air roasting method, like this one, tend to produce a high-toned flavor profile due to effectively blowing the smoke off the beans during the roasting process.
Again, this is the alchemy part of the hobby so the temperature, roast time, color, etc.. will be dependent on personal tastes. Most people tend to prefer a darker roast, so for a first attempt, or if you don’t have a thermometer, a good rule of thumb is stop the roast as soon as you hear the second crack, which is usually a Full-City or Light French Espresso roast. Here’s some basic temp/roast info from the ‘Home Coffee Roasting’ Book:
~400F – Light Brown – Cinnamon/Light Roast (First Crack)
~425F – Medium Brown – Medium Roast/American
~440F – Medium-Dark Brown – Full City/Light French Espresso (Second Crack)
My popper tends to first crack around 4-5min, and second crack around 9-10 min.
I usually keep a log of each roast, with the following information:
- Date
- Bean origin/information
- Time at ‘first crack’ (FC)
- Temperature at FC
- Time when roast is stopped
- Time/temperature at ‘second crack’ (if roasted that long)
- General color at end of roast
Once you’ve reached your desired roast, turn off the heater and crank the fan onto full. You will be surprised at how quickly the fan cools off the beans due to the design of the popper. Within a minute, the temperature should be under 200F and you can transfer the beans into a colander and shake them around for additional cooling. Here’s a picture of a fresh medium-dark roast:

Once you’ve completed the roast and the beans have cooled down, you can transfer them into a jar or tupperware container. You need to let some of the CO2 burn off the beans, so they need to sit for a minimum of 12hrs. Once you open the container from a fresh roast, you will really understand what fresh roasted coffee is all about.
A QUICK NOTE ABOUT SAFETY!!
When roasting coffee, these poppers get HOT. There is also a lot of smoke from the beans on darker roasts, which will set off smoke alarms if not properly ventilated. I’ve already ruined one popper when the smoke alarm and entire building fire alarm went off, in which i panicked and turned off the breaker, which essentially killed all airflow to the popper. Airflow without heat is actually a very effective cooling mechanism; no airflow with a heater @ 450F is not. Essentially the plastic fan melted into the heating element before I realized what was happening, in a near fission experiment. If you get into a situation where there is a ton of smoke and potential fire hazard – KILL THE HEATER BUT LEAVE THE FAN ON! Or, get a fire extinguisher and prepare for a mess.
Making Coffee
We’ve experimented with a number of methods, and found the old 60′s style Chemex coffee makers with the square filters to make the best cup of coffee. It removes any bitterness out of the taste and is a quick, easy process.
Here’s a pic of our setup:

Basically, here are the steps:
- Start boiling some water
- Grind the fresh roasted coffee beans in a quality burr grinder. Cheap grinders will not uniformly grind the coffee which results inconsistent taste.
- For 2-3 cups of coffee, we use 3-4 heaping teaspoons of fresh coffee, dumped into the 4cup Pyrex measuring cup
- When the water just starts to boil, pour in 3 cups of water into the Pyrex measuring cup, and cover (to retain heat)
- We also pour some excess hot water into the cups we will be using, so that the cups are already warm and heat isn’t transfered away from the brewed coffee
- After about 2-3 minutes of steeping, pour the coffee into the paper-lined funnel of the Chemex coffee maker to drip
- Enjoy fresh, home roasted coffee!!

We are surprised at how conditioned people are to cheap, crappy coffee that has been freeze dried and sitting on a shelf for who knows how long. Coffee is an incredible fruit, that has something like 2000+ identified substances contributing to 700+ different flavors. Some are bold, some are subtle, and the roast profile and freshness of the coffee are such an important part of the end result.
Happy roasting!!
Regards,
- Stevan
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Links:
Defacto Bible on Home Coffee Roasting – http://www.amazon.com/Home-Coffee-Roasting-Revised-Updated/dp/0312312199
Sweet Maria’s – http://www.sweetmarias.com/
Engadget Popcorn Popper Modification – http://www.engadget.com/2006/02/28/how-to-make-a-popcorn-popper-coffee-roaster/
Chemex Coffee Makers - http://www.chemexcoffeemaker.com/