Home Coffee Roasting

Frankenroaster.

Wow, it has been a long time since I posted.  Sometimes life gets in the way.  It shouldn't, but it does.  I guess that is the price we pay for being human.  It kind of puts it in perspective when you think about the human sitting on a bench with his dog.  The human is thinking about work, money, relationships, politics, world events, taxes, etc.  And the dog is just thinking about his human.  It takes a lot of work to shut that other crap off.  One way I try to do that, with varying degrees of success, is to be mindful.  Basically, getting lost in the moment and thinking about only that one thing, whatever it is.

Which leads me to this topic.  The kitchen is one place where, if I make an effort, I can get lost in the moment.  Become mindful.  Get into the flow.  Whatever you want to call it.  I tend to make things in the kitchen that most people just buy.  Some things are because of how sick I am of the ingredients in store bought products, like pickles.  It is getting hard to find any without preservatives or artificial colors.  So, I tend to make my own.  But other things I do, because it tastes better and/or I want to understand the process.  Enter the crazy contraption above.  I called it Frankenroaster for lack of a  better term, but I think it is a apt name.  This all started because I love coffee and finding really good coffee is difficult in my small town.  So, I started doing some research into roasting my own coffee and found that it isn't really that difficult.  You can roast coffee just like they used to do many years ago and use a frying pan.  So, I scoured the internet and found that people did one of the following:

• Paid a crap ton of money and bought a small commercial roaster.  We are talking at least 4 digits for one of these.  Too rich for my blood.  I would rather have a new motorcycle for that money.
• Bought a home use roaster.  These go for around $200 for a cheap one, to a few hundred.  Still a pretty big investment for a first time roaster not knowing if it is worth the effort or not.
• Used a popcorn popper.  Either an air popper or the one with the hotplate, dome, and arms that agitate the beans.  This is actually a pretty good way to go.  We will talk more about this in a bit.
• Used a frying pan, although, you hear a lot of comments that you "can" use a pan, but not much about people actually using one.
• Since most of the posts were by guys, there were also a lot of massively over-engineered DIY roasters.  Ingenious and worthy of bragging rights, but I want something I can store in a cupboard and can set up in about 2 seconds.

So, popcorn popper it is.  Now, there are a few considerations for roasting your own coffee:

• You need something hot enough to roast the beans.  We have already established that a popcorn popper will work.  A hot air popper will get up to around 450 F.
• It makes a lot of smoke.  And to answer your follow up question, no, it does not smell awesome like fresh roasted coffee.  It smells like burnt coffee and will quickly set off your smoke detectors unless you have a good vent hood, or do it outside.
• Depending on the type of coffee/supplier, there can be a lot of chaff that comes off the bean that needs to be separated.  A hot air popper will do that automatically for you, but unless you have a way to catch it, it ends up all over your kitchen.  A regular hotplate style popper won't do that for you, so you need to take care of that during the cooling process.
• And, finally, you need to cool the beans to stop the roasting process.  So, in the case of either popcorn popper, you need to dump the beans into a sieve, or on a screen and hit it with a fan.  In the case of the hotplate style popper, now is when the chaff will blow off, and cause the same issue we talked about in the bullet above.

So, given all this information, I decided on the hot air approach.  It is worth noting that there is a roaster or two on the market that are based on the hot air approach.  Both ratings and price turned me off.  One that had decent ratings (except for the person who had one start on fire) was still close to $200.  I really didn't want to risk that money for something I didn't fully understand yet.  So, I found a Poplite air popper on Amazon for $16.  Not much to spend if things don't work out.  So, this was the method:

• Place 1/2 cup of green coffee in the popper
• Put the cover on
• Set up my small clip on fan nearby for cooling
• Place it on my cook top with the vent hood at full bore
• Plug it in
• Place mesh strainer over the output to catch the chaff
• Roast the coffee through first crack and into second and catch about 30% of the chaff while the rest goes all over the place and also losing quite a few coffee beans because they blow out way more than popcorn.  I assume it has something to do with the larger surface area of the coffee bean.
• Once roasted, unplug the popper, blow out the strainer in the sink, again, making a mess, and pour the beans into the strainer
• Hold over the fan and stir with a spoon until cool enough to handle

The result was a decent batch of coffee.  A messy cook top.  My clothes and hair smelled like burnt coffee.  And it was kind of a pain in the ass.  But, the final product was good enough to merit another round.

Fast forward to Frankenroaster.  This design was based on the hot air roaster I talked about above, because it made sense to me, although I still didn't want to shell out $200.  I ended up making mine for under $40 and the only part that can go bad is the popper, and I can replace that for about $20.  What I used to build it:

• 1 - Poplite popcorn popper
• 2 - single-pole toggle switches (120V of course)
• 1 - 15 oz food can with both ends removed.  It fits nice and snug into the throat of the popper.  I could have used a piece of 3" aluminum duct, but I thought the reducer (next bullet) would fit right into the popper.  It did, but has a lot of gap which beans got caught in, so not wanting to go back out in the dead of winter to get a piece of duct, I was resourceful and found that a 15 oz can works.
• 1 - 4" to 3" aluminum duct reducer
• 1 - 4" piece of aluminum duct about 8"-10" long.  Mine was an adjustable bend as I was experimenting with the design.  In the end, straight up works the best in my opinion.
• 1 - 4" dryer vent clamp
• 1 - piece of single layer cheese cloth for the chaff catcher
• A drill, drill bits, screw driver, utility knife, pop rivets, and a couple wire nuts.

Warning:  If you are not handy and understand electricity and wiring, don't attempt this.

The method:

• Open the popcorn popper by removing the screws on the bottom of the case.  You will end up with the bottom of the case, three screws, a fan/heat source, a metal throat, and the main case.
• Remove every other vent rib on the bottom of the case to increase air flow.
• Figure out which wire is the main power and which one leads to the main heat coil.
• Drill two holes the same size as the toggle switches.
• Wire up one switch for the main power and one for the heat source.
• Mount the switches and reassemble the popper.
• Test it to make sure your switches are correct.  I found that the main heat switch, when off, still produce a small amount of heat, but only slightly higher than room temperature.  Still enough to cool the beans and I didn't want to get to in-depth on rewiring it.  Simple is always better.
• Since the reducer duct didn't fit into the can very well, I chose to push the can through from the 4" side.  Since the can was steel and the duct was aluminum, I forced it through fairly easily.  Wear leather gloves, this is just an emergency room visit waiting to happen if you don't.
• Add the 4" duct and secure all pieces with a few pop rivets.  This is what I will refer to as the chimney assembly, for lack of a better term.
• Clamp the piece of cheese cloth on the top.
• Remove the Poplite label and make your own label, plus one for the main power switch and one for the heat switch.
• You have a coffee roaster!

Now that the hard work is done, what is my new and improved method for roasting coffee?

• Take roaster out of cupboard and place on cook top.
• Turn on vent hood.
• Remove the chimney assembly.
• Dump in 1/2 cup of green coffee beans.
• Replace chimney assembly.
• Plug it in.
• Turn on the master power to make sure the beans are moving around freely.
• Turn on the heat.
• Sip a cup of coffee an listen.
• First crack will sound like popcorn popping.  Pretty loud.  You need to go through this stage in order for the beans to be roasted.
• Once it is done with the first crack, it will quiet down, but soon will start the second crack.  Second crack sounds like Rice Krispies.  Once it starts second crack, you have a light roast and the further through you go, you get a darker roast.  You will need to experiment to find what you like, but since this device can only do about 1/2 cup at a time, it is easy to do.
• When it is roasted just about to where you think you want it, turn off the heat and let the fan cool the beans.  This is the beauty of the air popper.  I find that 2-3 minutes is about enough.  You can always use an infrared thermometer to monitor things.  I got mine on Amazon for about $16.  I love Amazon.
• Turn off the roaster while removing the chimney assembly at about the same time.  It will keep the chaff at the top on the cheese cloth.  Use a towel or pot holder because the metal will still be too hot to handle with bare hands.
• Pour the coffee in a container.  Depending the type of beans you use, it will be ready to grind in 1-4 days.  Don't grind it right away.  It is not ready and you will be disappointed in the result.

Stuff I have learned along the way:

• Coffee doesn't smell wonderful when you are roasting it.  It stinks.  So will your house if you don't have a good vent.
• Coffee needs to out-gas before you should use it. 
• Some coffee has very little chaff and others have copious amounts.
• Some coffee is very noisy during first crack and some is not.
• Some coffee is very noisy during second crack and some is not.
• Some coffee, such as my personal favorite Papua New Guinea, goes through a huge flavor profile change over 4-5 days.  It starts out, as all do, burnt smelling, then after a couple hours have huge caramel tones.  This starts to fade over 3-4 days, but the flavor becomes more complex.  Experiment with it.  It's fun.
• I may not be a world class coffee roaster, but it tastes better than most anything I can find from a coffee shop.  You simply can't beat small batch roasting.  This is the coffee equivalent of home brewing.
• Amazon is a great place to buy green beans.  Even better if you are a Prime member.

Well, there you have it.  Anyone can roast coffee at home.  I roast about 2-3 time per week and is quick to do.  For 1/2 cup, you are talking around 10-15 minutes, of which you spend most time just listening, and hopefully, relaxing and dreaming about drinking it.  I hope you find this article interesting and useful.  I didn't really find anything like this when I was researching, so I wanted to help people who, like me, want to take the time to roast their own coffee and don't mind spending about 30 minutes total to build a cool roaster that I don't feel is over-engineered.  I am an engineer by profession, and we like simple, elegant solutions.  Well, one out of two isn't bad.