Coffee Roasting With a Hot Air Popper





Introduction: Coffee Roasting With a Hot Air Popper

I'm well on my way to complete coffee snobbery.   Essential to achieving this is being able to roast your own coffee from green coffee beans, which gives the most amazing fresh flavor and scent.  Not to mention the ability to casually mention you roasted this particular cup of coffee yourself...

Here's my inventory for home roasting:

Hot air popcorn popper
Green coffee beans
1/4 cup measuring cup
medium strainer
round bottom stainless steel bowl
flat bottom stainless steel bowls (I use 2 of them)

The popcorn popper is an "Air Crazy" by West Bend - I got mine at Target for about $20.  Ignore the terrible reviews - you aren't using it for popcorn.

I got the strainer and round bowl from the kitchen aisle at Smart N Final - any big retailer should have them.

The flat bottom bowls came from Petco - yes, they are dog food bowls. 

I get my Green Coffee Beans from Sweet Maria's in Oakland California - they have a great mail order website.  I recommend a 4 lb sampler to get started  - that's plenty of coffee to learn how to roast. 

Step 1: Set Up Your Roasting Station

I do my coffee roasting outside for a couple of reasons.  Firstly, the hot air method expels a lot of chaff, and secondly, She Who Must Be Obeyed doesn't like the interim smell (which resembles either grass or charcoal, depending upon who you ask). 

I have a bistro table outside, right next to a power outlet. 

Step 2: Add the Green Coffee Beans, and Start the Roast

I usually roast in small batches, and I have found that a quarter cup or a little more is a good starting point for this machine.  Your mileage may vary, due to ambient temperature and (more importantly) the voltage at your outlet. 

Pour the beans into the popper, and turn on the switch.   It will be noisy -- another good reason to be outside. 

Step 3: Monitor the Roast

In a minute or less the beans will change from green colored to a light brown.  This process will continue and the beans will darken as the roast.   Chaff will fly up out of the top of the popper as well.   

We are listening for the beans to crack -- it is a popping sound, and is a bit like popcorn.  You need to continue the roast until all the beans have cracked once - if you don't roast long enough, your coffee will taste like hay or dry grass. (Bleah!)

  Depending upon how dark you want your roast, you can stop after the first crack is done or you can continue the roast a while longer, waiting for a second, more subtle crack. 

Here's a very short  youtube video of the process -- the ambient noise level is high, but the cracking is audible as clicks. Notice the flying chaff as well.  

Step 4: Dump the Roasted Beans, Cool Them and Remove the Chaff

Once you are satisfied that the beans are fully roasted, turn off the popper and dump the beans into a bowl.  Pour them back and forth between the bowl and strainer to cool the beans and to allow any remaining chaff to blow away.  Don't stress about the chaff - it doesn't affect the flavor too much is you don't get it all out. 

Once the beans are mostly cool I dump them into one of the dog food bowls to further cool.  I usually roast about four batches at one session, and having two spare bowls allows me to fully cool two batches while a third is roasting.

Step 5: Store the Beans, and All Your Roasting Supplies.

Pour the cooled beans into an air-tight storage container.  Sweet Maria's labels come off the ziploc bags easily, making it simple to label your beans. And you should label them -  imagine the horror some morning if you are expecting a nice light Costa Rica blend and you accidentally grind up some Dark Roasted Java!  Shudder the thought....

All my supplies fit neatly into a flip-top storage box, making it easy to store between roasting sessions. 

Now, go have a cup of good coffee, eh?



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    16 Discussions

    it's better to preheat the popper by running it for 4 or 5 minutes before adding the beans

    Nice idea. We hardly ever use our air popper for popcorn. Do you think this will make our next batch of air popcorn taste like coffee? Or worse, like burnt hay?

    Would it matter if the coffee cooled in a glass bowl, or does the steel's "heat sink" properties help the coffee cool more quickly?

    I'm ready to give this a try.

    1 reply

    it does not make the popcorn taste like coffee, but not the picture of the inside of the popper here, if it doesn't have the vents around the side like that you won't get a good even roast. the other kinds won't churn the beans.

    I use corelle bowls and it cools fine, I don't think metal would make enough difference vs the thermal mass of the beans.

    I think dual purposing the popper is not the best idea. I expect the popcorn would taste off - maybe coffee flavored, maybe not. Report back if you try it :-)

    I think the steel works really well as a heat sink, better than glass would. Even though a lot of the cooling happens when you pour back and forth from strainer to bowl, the bottoms of the dog bowls still are warm after the beans have rested in them for a while. Glass is a good insulator, and would probably not draw the heat away as we want to happen.

    2 replies

    I have dual purposed, there is no flavor transferred. however, poppers that are good for roasting make poor poppers as they tend to expel many kernels with great force when the first one pops. you really want a spinning chamber for popcorn and not for beans.

    I'd heard you could do this, never been bothered to have a try, but looks fun, I think I've got a popcorn machine that's missing its lid, that'll work perfectly I guess!

    both of my popcorn poppers have a heater cutoff fuse, or an automatic overheat shut-off, which shuts the machine off before the first crack is completed.

    Any recommendations on which brand or models don't have this auto shut-off?

    both of my popcorn poppers have a heater cutoff fuse, or an automatic overheat shut-off, which shuts the machine off before the first crack is completed.

    Any recommendations on which brand or models don't have this auto shut-off?

    Do you grind the beans when ready to enjoy that cup of joe?

    2 replies

    Oh yes. As a Coffee Snob, I am required to grind the beans just before brewing - no mass grinding for me. I invested in a nice Capresso brand burr grinder a few years back, when I first started down the path to Snobbery and started buying whole beans instead of ground coffee.

    One of the best parts of fresh grinding is the scent - the coffee aroma is way more intense than that can of Folgers in the cupboard. Even my non-coffee drinking wife agrees the scent is more appealing.

    Don't forget to burp your coffee for about 24-48 hours after roasting. Or simply leave it uncovered. Leaving it sealed while it emits large amounts of CO2 can produce very acidic coffee.

    2 replies

    Great point! I usually leave the beans in the steel bowls overnight to out-gas before they go in the jar.

    do you know how hot the bean needs to get? I've thought about roasting beans to wean my dependence on coffee brands...

    1 reply

    Wikipedia :-) tells me that roasting temps are from 200-250 degrees C.