Home Roasting

Generalities:
As opposed to other food crops, coffee freshness is not determined by harvest date. Fresh coffee is defined by the time since roasting.  Green unroasted coffee has a wonderful shelf life. If kept under the right conditions, green coffee beans can keep its original cupping character, without spoiling, for up to a year or two from harvest date.

If freshness is not enough, roasting your own coffee beans is far more economical than buying already roasted beans. Green coffee beans are generally half the cost of the same type of bean roasted. Saving money is especially true for avid coffee drinkers. Hence, home roasting has been gaining considerable popularity.

Roasting is determined by the rate which heat is applied and the degree of roasting. Roasting chemically changes the characteristics of raw coffee beans dramatically. Over five hundred volatile substances are produced by roasting. Controlled heat causes coffee beans to emit a cracking sound as the beans expand with carbon dioxide and water.  Rupturing the walls of cells within the beans, this expansion liberates aromatic oils. Consequently, these oils define the flavor and aroma of the roasted coffee bean. The timing between these “cracks” is one of the many indicators that helps the roaster determine how light or dark a roast the beans will have.

Coffee roasting is advanced by experience.  Practicing home roasting makes you one batch closer to determining your personal favorite. No textbook or factsheet can completely cover the finite details of roasting since the senses are involved.  The “best roast” is not standardized because everyone’s taste preference differs- mild or strong, bitter or bright, etc.  Also, because coffee beans come in a variety of densities and sizes, different origins, varying growing altitudes, soil type, and cultivars, there is no one-standard, fit all roast technique. Each coffee bean has its own character which can be highlighted by means of its own personalized roast process. This precision is fine tuned by experience and can easily become a fixated passion.
 

Coffee Roasting Basics 101:
Home roasting green coffee beans allows full control over freshness. Coffee flavors peak 24 hours after roasting and last up to a week thereafter. So by home roasting, individuals can be creative, making new blends according to likes, exploring different origins, but ultimately tasting all the goodness true fresh coffee has to offer.  Individuals can orchestrate the roasting process according to their preference. Coffee Basics 101:

• Organization is advantageous. Just like any other process, having your supplies on hand and nearby will save time and error. Roasting coffee takes between 5-15 minutes, depending on roast preference and the roasting technique. Being organized prevents possible errors like scorching while looking for the colander to cool the beans in. This could also prevent more of a mess, like chaff flying around as you toss haphazardly away from the sink or away from an open window. 
• Colors will change as the roasting process progresses. The green coffee beans will turn lighter yellow and gradually darken from tan to brown. Roasting is especially important toward the end and should be closely monitored as the last few minutes can make a big difference.
• Temperatures must generally reach between 370oF to 540 oF for green beans to roast. Lower temperatures are allowed if air is circulating.
• Whether with a wooden spoon, crank, or automated- coffee beans must constantly be in motion. This prevents uneven roasting or scorching.
• Steam emits from the coffee beans as it roasts.  Trapped water and carbon dioxide boils out and escapes. This soon turns into a light smoke as sugars caramelize and oils seep out. Beans expand. This smoke thickens as the roast progresses. Proper ventilation is necessary as roasted coffee gives off considerable smoke with darker roasts.
• Chaff comes off freshly roasted coffee beans. It is the dried, thin membrane, or outer skin of a freshly roasted bean. This can be messy. If an automated roaster is not yet among your kitchen gadgets, a few shakes in a stainless steel colander outdoors can easily help sift off the chaff.  
   

The Senses Involved:
Knowing when to stop roasting is major in roasting your own fresh cup. This precision comes with experience, so practice, practice, practice. The following factors are combined when determining how dark or light a roast will be:

• Temperature: Roasting machines are equipped with this feature. If a crank styled popcorn popper or stovetop cooker is used, a cooking thermometer will do fine.
• Color: Being familiar with your favorite coffee roasted can assist as a visual aid.
• Aroma: Initially, when coffee beans are roasted they emit a wet grass smell. This transforms into an increasingly smoky smell.  As the roast progresses, the smoky smell becomes stronger as the beans darken and whatever sugars in the beans burn away. It is enough to set off a smoke alarm.  So, when roasting the beans over the stove, make sure the ventilated air hood is running or have an open window with a fan nearby.
• •Sound: After certain temperatures, the chemical reactions within the beans emit a popping sound. Two distinct cracks are recognized by roasters, the latter being less defined though definitely louder. These are generally two important stages and can be gauged by temperature for specific beans. Again, there is no definite rule, but this is only meant to guide toward refining our senses.
• Time: Timing can only be considered a factor to achieve a desired roast, if all previous factors for the last roast were the same: Are the same coffee beans (type, size, and weight) being roasted? If these are the same, and timing was properly recorded last time in producing your “perfect roast,” then it can be taken into account in producing your next roast. When using a home roasting machine or oven for coffee roasting, this is particularly useful when proper notes are taken for each type of coffee.
   

After Roasting:
After a batch of coffee beans completes roasting, it must be cooled immediately. Even though the source of heat is taken away or shut off, the beans will continue to cook from the heat already collected. Normally, a home roasting machine has an internal cooling system. If the stove top or popcorn popper method is used, a colander is a great solution. A few shakes outdoors in a colander sifts out the chaff and cools the beans simultaneously. Nature can be helpful if a slight breeze is available, as this removes the chaff as you are tossing the beans. A small amount of leftover chaff will not significantly affect the coffee flavor as it is tasteless, so do not fret if all of the chaff was not removed. 

Coffee flavors peak 24 hours after roasting and last up to a week thereafter. Though not necessary, most coffee enthusiasts favor the roast between one to two days after roasting.  After this rest period, the coffee beans stabilize in their flavor-producing oils and are ready to be extracted. 
 

Enjoy!
Home roasting is best defined as a never ending experiment- a fun one at that. What began as a humble test of trying to concoct my own favorite coffee roast in my very own kitchen, turned from part time hobby into an ever growing pursuit.  We encourage everyone to take the same route: do not stress.  Relax, enjoy, and explore. An individual can dedicate a lifetime and still have plenty more to learn, due to the never ending crops variations, particular coffee beans availability in seasons come and gone, and roasting tricks & modifications.

Entertain family and friends with your own fresh brew. Coffee talk the thrill of grinding your first roast.  Have them whiff the caramels and yummy aromas wafting up from their own mugs.  Take pleasure as you hear them sigh in content as they take their first sip, all while relishing in the “I made this” rumba. Enjoy!