Coffee Roasting guide for new home roasters

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Green Coffee Beans

The basic form of the coffee bean after being processed is the green unroasted bean. Green beans can be preserved for more than one year without losing their characteristics.

Roasters buy unroasted coffee in bulk and roast it using professional roasting equipment. Home-Roasters buy unroasted coffee and roast it using cheap roaster designs which are very easy to build and use. These include woks, corn poppers, heatguns, convection ovens (turbo crazy), barbecue drums and so on.


Coffee Roasting

One coffee tree produces one pound of roasted coffee per year! The first product of a coffee tree is a the raw green beans. Green beans get processed, machine (water processed) or sun-dried (natural-dry processed), graded into quality categories and then channeled to the wholesale coffee market

The second step after raw beans processing is roasting. Green beans get roasted using high temperature and then packaged for use in coffee shops or the home market. Commonly coffee for use at home gets ground before being packaged.

Coffee is best 4 to 24 hours after roasting. For espresso peak flavor is reached 1-3 days after roasting. During this time, coffee emits enough C02 to keep the oxygen (that will eventually make it stale) at bay. The CO2 production is known as degassing. As a general rule, darker roasted beans tend to de-gas quicker than lighter roasts, which will de-gas and be at their peak after a number of days. Also, lively coffees that haven’t had long to de-gas can sometimes be a joy in a french press or vac pot, but for an espresso lively isn’t normally a good attribute.

The essential flavor oils are delicate, and fade or become tainted quickly despite all our interventions. Stored as whole beans in an airtight glass jar in a dark place, coffee can stay "fresh" for roughly 5-6 days.

Mass market coffees are usually coffees of (less than) average quality, roasted badly and packaged sloppily and cheaply. The main emphasis is on marketing and logistics costs. Rarely you can find companies who provide coffee packaged with one-way valves, or NO (like Illy or Mollinari). Coffee lovers strive to find the best coffee sometimes available from their local neighborhood micro roasters.

Home Roasting

The last years home roasting has started becoming a trend again, especially in the USA and Northern European Countries. Home roasting gives many benefits it's probably the only way to deliver the best coffee possible. Benefits include:

    * Freshness
    * Beans quality
    * Ideal blend
    * Cost
    * A new experience, a sense of self accomplishment and fun!

Description of the roasting process

Roasting is basically like cooking or making popcorn. All you need is heat and good heat dissipation. Basic methods include wok roasting, stovetop poppers, popcorn machines, hotgun method, barbecue drums, stir crazy, dedicated roasting machines for home use like the HotTop or the iRoast and the list goes on...

For the first few minutes the bean remains greenish, then turn lighter yellowish and emit a grassy smell. The beans start to steam as their internal water content dissipates. The steam becomes fragrant. Soon you will hear the "first crack," an audible cracking sound as the real roasting starts to occur: sugars begin to caramelize, bound-up water escapes, the structure of the bean breaks down and oils migrate from their little pockets outward. After the first crack, the roast can be considered complete any time according to your taste. The cracking is an audible cue, and, along with sight and smell, tells you what stage the roast is at. Caramelization continues, oils migrate, and the bean expands in size as the roast becomes dark. At this point a "second crack" can be heard, often more volitile than the first. Small pieces of the bean are sometimes blown away like shrapnel! As the roast becomes very dark, the smoke is more pungent as sugars burn completely, and the bean structure breaks down more and more. Eventually, the sugars burn completely, and the roast will only result in thin-bodied cup of "charcoal water". When roasted, coffee releases over 800 components that build up its taste and flavours. This makes coffee one of the most complicated foods around, and such an unique organic product.

First and Second Crack

First and second crack are sure signs of roast development. First crack is an expansion of the bean and a warming of the coffee oils, creating an exothermic reaction, which means the beans are giving off heat as a consequence of their expansion. This results in a popping noise similar to that of popcorn. Second crack sounds more like a quick crackle, similar to the sound of foil rattling. One thing to beware of is, sometimes, first and second crack can merge into each other. It’s important to listen intently during these stages.

Heatgun Roasting

The simplest hands-on roasting method (if we forget about wok roasting) is heatgun roasting. You'll need the following:

   1. A heatgun capable of providing at least 500 F degrees, and air flow of 14 CFM. The higher the wattage the better. An adjustable power setting is preferred. Makita is one of the best heatgun brands. The heatgun I have successfully used was 2000W and priced only 11 euro!
   2. A roasting vessel. This could be an adequately sized stainless steel dogbowl, or even better a stoneware bowl. The bigger the roast batch the bigger the bowl. Using a classic dogbowl as a typical example, a 32 oz. bowl accommodates one cup of beans by volume.
   3. A long wooden spoon for stirring.

Begin by assembling all the equipment and pour one cup 180ml green coffee beans into the bowl. Put the dogbowl Outside the house or in a covered and very well-ventilated area (this method does produce copious amounts of chaff and roasting smoke), put the dogbowl on a heatproof surface. Start up the heatgun (I use the high setting of my 2000W heatgun) and hold the muzzle of the gun approximately 10cm from the surface of the beans, stirring continuously with your other hand. After approximately four to six minutes, the beans will begin to smell grassy and turn a light tan in color. After a while the beans will become lighter and get a cinnamon color. Chaff will start to blows off the surface of the beans. Move the muzzle closer or further from the surface of the bean mass as dictated by how fast the roast is progressing, and and how fast you want it to go. Just don't burn any beans!

At approximately 7 minutes, you should reach first crack, and second crack at about 8-9 minutes. The second crack is usually less noticeable and quicker than the first roast, and produces more smoke. I advise you to stop the roast at the start of second crack, the first time you home-roast. When the roast is complete, quickly dump the beans into a metal colander or cool the beans in the usual fashion. If the heatgun has a 'cool' setting, turn the heatgun to cool and let it run for a few minutes until it is cool to the touch. This will extend the life of the heating element in the heatgun.

The time to complete a roast also varies by volume; a one cup roast typically takes about seven minutes, a two cup roast typically takes about eleven minutes and a three cup roast typically takes about 14-16 minutes (these times do not include cooling). If you like roasts with more brightness/acidity especially for your drip coffee or french press, experiment with quicker roasts. Decaf coffees will generally roast in less time for the same volume of coffee.

The total time is very dependent on volume, heatgun used, the roasting vessel used, ambient temperature and operator technique. If you are roasting in very cold temperatures, the roast time may be prolonged or you may want to put the roasting vessel into a heatproof box, tall stockpot or other container to help retain the heat. The best guide to the roasting process will be your eyes and ears as you monitor the roast.

You can visit my E-bay store FreshCoffeeShop for a more advanced version of this guide. You will also be able to find an extensive variety of green coffee beans!

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