How To - Roasting Coffee At Home

Roast your own coffee at home!

Roasting coffee at home is cheap, fun and you'll have bragging rights to some of the freshest, best tasting coffee around! Impress your friends and subvert the evils of the big coffee business. Your final product will take 10 minutes to make, be about half the cost of roasted coffee you buy at the store or cafe.

roasting stuff

What you'll need

popcorn popperSome poppers will work better than others, but the only detail is that absolutely necessary is air vents that are on the walls of the popper, not holes in the center, floor of the chamber. See the picture below for an example of side vents:

We've had successful roasts with the Poppery I & II, Kitchen Gourmet (Walgreens) brands, but there are many others. Decades old popcorn poppers sell on ebay for $20-60 ---- that's often because folks are willing to pay a premium to use them as coffee roasters.

 

Acquiring green beans

green coffee beansFinding green coffee beans is not as hard as you might think. Coffee shops that roast their own are usually happy to sell to you, most will do so at half the cost of roasted beans. You can also find them at some health food stores (Rainbow in SF) and online. The going rate for standard fair trade / organic beans is about $4-6/pound ($9-14/kg), though it might be lower if you buy it by the sack (75kg or ~165lb worth) and a lot higher if you're interested in super premium or usual coffees (like cup of excellence,kona, jamaican blue mountain, or kopi luwak :) ).

Two great online suppliers are 7 Bridges, which sells organic coffee roasting AND home brewing supplies, so you can get your fix of two awesome things in one place and Sweet Maria's, which has a virtual encylopedia of coffee and home roasting information, many of the worlds very best coffees.

An alternative source is online coffee bean buyers clubs, two are Green Coffee Co-op and Green Coffee Buying Club

The Process

Depending on the size of your popcorn popper you'll want to add between 1/2 cup and 3/4 cups of green beans. The idea is to get them to bounce around so they roast evenly (watch the video below to get the idea...). Start conservatively and move up. The roasting process doesn't take long so you can always do two roasts back to back.


Original Video - More videos at TinyPic

Put the top on your popper, your bowl in front as you would to catch popcorn. This is going to catch the coffee skins, called chaff, that will be expelled as you roast. Chaff makes great compost, especially for plants that like more acidic soil. Sometimes it also likes to fly around and you'll find it in your hair later in the day.

coffee chaff

The Roast

You can remove the lid of your popper to take a look at your beans, stir them around if you wish. Over time they will get darker and darker, if you leave them in long enough you'll start hearing loud 'pops.' Different stages have of the roast have different qualities and are known by different names. stages of coffee roast

Some varieties of coffee are better lightly roasted, others dark -- most will include some information on this, or you can ask your local coffee shop. on top of this people have their personal preferences, so it's really up to you! some like darker roasts while others say lighter roasts preserve more flavor. Experiment!!

Roasting table via wikipedia

Roast level Notes Surface Flavor
Light Cinnamon roast, half city, New England After several minutes the beans “pop” or "crack" and visibly expand in size. This stage is called first crack. American mass-market roasters typically stop here. Dry Lighter-bodied, higher acidity, no obvious roast flavour
Medium Full city, American, regular, breakfast, brown After a few short minutes the beans reach this roast, which U.S. specialty sellers tend to prefer. Dry Sweeter than light roast; more body exhibiting more balance in acid, aroma, and complexity.
Full Roast High, Viennese, Italian Espresso, Continental After a few more minutes the beans begin popping again, and oils rise to the surface. This is called second crack. Roasters from the U.S. Northwest generally remove the beans at this point. Slightly shiny Somewhat spicy; complexity is traded for heavier body/mouth-feel. Aromas and flavours of roast become clearly evident.
Double Roast French After a few more minutes or so the beans begin to smoke. The bean sugars begin to carbonize. Very oily Smokey-sweet; light bodied, but quite intense. None of the inherent flavors of the bean are recognisable.

If you want to know more about the terminology (French Roast, Full City, etc) check out, A Pictorial Guide to Roasting at Sweet Maria's.

Note: Coffee roasting can produce some smoke, so if you are roasting inside you should do it near a window if possible. The darker the roast the more smoke you'll produce. Also be prepared to watch your roaster so nothing awful happens (it usually won't).

Early On

lighter

Almost time to cool!

darker

Cooling

After your beans get how you like them, cool them quickly by dumping the popper into a colander and shaking things around until they're room temperature.

cooling

Storage and Settling

Leave to air out for 12 hours and then seal in an air tight container for use, or stick in your coffee grinder's holding area. Coffee typically tastes best 24 hours - 72 hours after roasting, you might be inclined to try it immediately, but won't have the full taste. Over time and some experimenting you'll see how the flavors rise, develop and fall. Happy roasting!

Mods

Some folks like to get more out of their coffee roaster and make some modifications to improve performance. I will add more about these soon, but will list some of the common modifications so you can search for these elsewhere for now if you are so inclined.

Popcorn poppers contain a thermostat that limits the temperature. You can sometimes get a better roast by increasing the heat if you remove this from the circuit.

Roasters have two parts: Something to move the beans and something to heat them. In the popcorn popper these two things are tied together. If you separate them you can have better control of the roast.

If you want to roast in larger batches you can remove the guts of the popper from their plastic housing and try extending your roasting chamber with a soup can!

Other Roasting methods

If you don't like the idea of roasting with a popper, there are a bunch of other ways you can roast coffee -- below are a few for inspiration