Coffee Roasting with a hot air popper

Picture of 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. 

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Step 1: Set up your Roasting Station

Picture of 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

Picture of 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. 
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.

If you are roasting for espresso, wait even longer, 5-6 days before they start to shine.

BradMartinson (author)  jtruesdell81 year ago
Great point! I usually leave the beans in the steel bowls overnight to out-gas before they go in the jar.
jrambo21 year ago
Do you grind the beans when ready to enjoy that cup of joe?
BradMartinson (author)  jrambo21 year ago
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.
baecker031 year ago
do you know how hot the bean needs to get? I've thought about roasting beans to wean my dependence on coffee brands...
BradMartinson (author)  baecker031 year ago
Wikipedia :-) tells me that roasting temps are from 200-250 degrees C.
BradMartinson (author) 1 year ago
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.
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!
stubbsonic1 year ago
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.