I’m proud to intro­duce Doug, my won­der­ful brother-in-law, who so gra­ciously wrote this post on how to roast your own cof­fee beans. I’ve been the lucky recip­i­ent of his deli­cious home-roasted cof­fee beans and can fully attest to their yumminess.

So, take full advan­tage of this once– in-a-lifetime divulging of coffee-roasting secrets. Go forth and roast beans to your hearts con­tent. Think­ing of call­ing my per­sonal barista Doug to roast them for you?

Fug­gitaboutit. Get your own brother-in-law.
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Greet­ings! Jen­nifer asked some months ago if I would be inter­ested in blog­ging about cof­fee. This was not just some ran­dom request on her part – in addi­tion to being an avid (rabid?) con­sumer of espresso, I also roast my own cof­fee beans. So I agreed to share my thoughts and mus­ings about this albeit low-thrill hobby on this forum.

Back­ground

My wife, Lau­rie (Jennifer’s youngest sis­ter) gave me an espresso maker as a sur­prise Christ­mas gift in 2005. Prior to that time, I reg­u­larly con­sumed one or more small espresso drinks (either a cap­puc­cino or latte) a day. I found the milk rather fill­ing, so I began drink­ing plain espresso. Hence, the idea for my gift…

It is no secret that the main “sup­plier” of my desired bev­er­age was Star­bucks – partly because of the fla­vor, but mostly due to the close prox­im­ity of a loca­tion next to my office. They pro­duce a bev­er­age of con­sis­tent fla­vor and qual­ity. To this day, I still fre­quent this chain when­ever I am away from home and require a “fix.”

Those of you who enjoy the robust fla­vor of espresso my have noticed that the Star­bucks vari­ety, while fla­vor­ful and con­sis­tent, has a car­bonized (or almost burned) taste. This is due to the roast char­ac­ter­is­tics (more about that in a minute), which works espe­cially well for milk-containing drinks – cap­puc­ci­nos, lattes, mac­chi­atos, mochas, etc. My own infor­mal sam­pling – which con­sists of noth­ing more sci­en­tific than not­ing the types of drinks ordered while I am wait­ing my turn in line – reveals that the vast major­ity of bev­er­ages made with espresso con­tain milk.

Around this time, the hus­band of one of Laurie’s law school class­mates asked if I had ever tasted “really” fresh-roasted cof­fee. I said “well, sure I have, hasn’t every­body?” “No” he replied, adding “most of the cof­fee that you drink was more than likely roasted weeks or even months ago.” I con­ceded that I hon­estly didn’t know, but had no rea­son to doubt him. He said “Unless you have ever roasted your own cof­fee, you have prob­a­bly never tasted fresh-roasted cof­fee.” He then pro­ceeded to explain to me how he roasted his own cof­fee at home, where he obtained green (unroasted) cof­fee beans, and how he built his own roaster.

The fact that he was a physics pro­fes­sor at the time at Geor­gia Tech and my own back­ground in chem­i­cal engi­neer­ing made me feel like we were relat­ing on a sci­en­tific level. Or per­haps it was noth­ing more than the fact that we were both hyper-caffeinated at the time. Regard­less, I imme­di­ately became inter­ested in explor­ing this idea.

First, I had to build my own roaster. You can buy any num­ber of qual­ity home-sized cof­fee roast­ers – but the idea of “build­ing” my own appealed to the engi­neer in me. OK, I really didn’t have to build much – a home-made roaster is noth­ing more than an old hot-air pop­corn pop­per with a ther­mome­ter added to it! Notice that I said “old” pop­per – the wattage on the newer mod­els, while safer for home use, do not come close to the 1400 to 1500 watts nec­es­sary to pro­duce a qual­ity roast.

Unless you hap­pen to have an old hot-air pop­corn pop­per lying about the house (I did not), you will have to search Ebay or your local thrift stores. The holy grail for home-roasters is the West Bend Pop­pery (Not the Pop­pery II). Other brands will also suf­fice – just be sure to select a model with the desired wattage. I was able to find a used Pop­pery in great con­di­tion for under $15 on eBay.

Next you will need a good ther­mome­ter, one that accu­rately reg­is­ters up to 460 – 470 degrees F. I found a good ther­mo­cou­ple on-line for $30ish, which works very well. With a pop­per and a tem­per­a­ture gauge, you are now ready to roast – oops! – for­got the beans.

You will need to find some green cof­fee – I use Sweet Marias (www.sweetmarias.com) as my source. They source beans from all over the world, and offer a brief descrip­tion of the fla­vor and roast tol­er­ance for each vari­ety that they sell. This site also offers great infor­ma­tion for the do-it-yourself enthu­si­ast, as well as offer­ing related prod­ucts (e.g. roast­ers) for sale.

Roast­ing

Before plug­ging in the appa­ra­tus and char­ring my first batch of beans, I read sev­eral dif­fer­ent arti­cles on home-roasting. I learned that the first “crack” (chem­i­cal reac­tions within the bean result­ing a loud audi­ble pop­ping noise, not unlike the crack­ing process in petro­leum refin­ing) should/will occur in the 400 – 410 degree F range. The sec­ond “crack” occurs in the 450 – 460 degree F range. For espresso, darker roasts typ­i­cally pro­vide the best outcome.

Degree of Roast

As the beans are heated they pass through sev­eral dif­fer­ent stages, marked by ever-darkening col­oration of the beans. At the con­clu­sion of the first crack, the beans are at the city roast level, and are suf­fi­ciently dark enough to brew cof­fee. The pro­gres­sion of roast stages is as fol­lows: City, City+, Full City, Full City+, Vienna, French, Charred (burned to a crisp). Espresso is usu­ally pre­pared with Vienna– or French-roasted beans, but Full City+ will also pro­duce a nice shot.

If you try this at home, please fol­low this one piece of advice – DO NOT ATTEMPT TO ROAST THE BEANS INDOORS – the amount of smoke and chaff will not endear you to any loved ones or pets – unless, of course, you feel the urge to test your home fire alarm. How­ever, if you do begin your own roast­ing exper­i­ments, try stop­ping at the var­i­ous degrees of roast (sev­eral on-line sites pro­vide tem­per­a­ture ranges for each) – you might be sur­prised at what tastes best to you.

Mea­sure out 4 to 5 oz of green beans (I use 4 ½ oz) to roast – any type of kitchen scale should work. One last item that you will need (in addi­tion to oven mitts) is a metal colan­der or sieve for cool­ing the beans after the roast (I use a large metal per­fo­rated pizza pan with a plas­tic back­ing tray). Once you have all of these items, and have a suit­able out­door loca­tion, you are ready to roast.

The First Roast

Set up the pop­per on a table or stand, and con­nect the power cord. Pour in the beans, and replace the top to the pop­per. Posi­tion the ther­mome­ter so that the end is at or slightly above the pile of beans. Now turn on the power – and begin wait­ing. It will take any­where from 5 – 10 min­utes to hear the first crack, depend­ing on the roaster and the ambi­ent air tem­per­a­ture. After the first crack sub­sides, sev­eral more min­utes will elapse before you begin to hear the much fainter (and quicker) sounds of the sec­ond crack. Stop­ping a few sec­onds after this point yields a Full City+ roast; I typ­i­cally go 30 sec­onds to a minute or so after the sec­ond crack begins for a Vienna roast.

If you con­tinue the roast much longer, you will notice that the beans have become oily and appear very dark and shiny, which is indica­tive of French-roasted beans. Should you con­tinue roast­ing past this point until the beans no longer appear oily, you will have suc­ceeded in car­boniz­ing the roast.

Fla­vor Characteristics

There are two main deter­min­ing attrib­utes to the fla­vor of cof­fee: 1) the ori­gin of the beans (vari­ety, loca­tion, and cli­mate), and 2) the degree of roast. The dark­est roasts “cook” away any fla­vor imparted by the beans, and leave only the degree of roast as the main fla­vor attribute. For my espresso, I pre­fer a Full City+ or a light Vienna, and typ­i­cally I will roast one batch to a Full City+ and a sec­ond to a Vienna, and then com­bine both batches.

I have ordered beans from many loca­tions around the world, and would be hard-pressed to name only one favorite. How­ever, if I could have only two sources, I would pick a vari­ety from Yemen, and a vari­ety from Suma­tra. To my taste, the Yemen beans have choco­late, dark, spicy fla­vors while the Suma­tra has more of an earthy appeal. Also, the Suma­tra beans become much more com­plex at darker roast lev­els. A close third for me would have to be the Brazilians…

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If you have any ques­tions for Doug– post them here and I will make sure he gets them.

In the mean time– wouldn’t these be great gifts for Christ­mas? Think about it– a great mug and a bag of home roasted cof­fee beans.