Mr. Green Beans DIY Coffee Roasting Guide

Home Coffee Roasting is fun and easy.  For a modest price and very little to no investment in specialized equipment, you can turn raw green coffee beans into a spectacular cup of coffee.  It only takes a little practice and you can easily create freshly roasted coffee that will rival even the best commercially produced coffees.

Why roast your own coffee?


Everyone seems to answer this in a slightly different manner, but the main ideas are the same.  The biggest reason for most people is that fresh roasted coffee just tastes better.  It’s smooth and rich and doesn’t have the acrid acidic bite that many associate with store bought coffee.  Unfortunately, roasted coffee has a very short shelf life and is only fresh for about 7-10 days.  Raw coffee on the other hand is shelf stable and can be easily stored until you are ready to roast it.  This allows you to roast only what you will consume within a reasonable amount of time, allowing you to always have fresh roasted coffee.  Another reason people choose to roast their own coffee is the price.  For as much as 1/2 the price of store bought coffee and as little as 6 minutes of your time, you can create delicious craft roasted coffee.   One big benefit of roasting at home is control. By roasting your own coffee, you gain control of the process and you can dial it in to your own personal preferences.   Great coffee roasted just the way you like it, and for half the cost! Why not roast your own coffee?


Basic Requirements for Home Coffee Roasting:

As complex as coffee roasting may sound it really come down to four key challenges that need to be addressed.  Each roasting technique and roaster answers these challenges in a slightly different way.  The basic challenges of roasting coffee are:



Green Coffee beans need to be subjected to temperatures between 460°F-530°F(240°C-275°C)

Bean movement or agitation

Either the beans or the air around the beans must keep moving to prevent uneven roasting and scorching.

Mitigating smoke and chaff

There will be smoke and chaff, which are both natural by products of the roasting process.  Different varietals and roast levels produce varying quantities, but you must have a way to deal with the smoke and chaff.

Cooling the roasted coffee beans

Once roasted, the beans need to be cooled quickly.  This can be accomplished a number of ways, the most common being placing the beans in a large metal colander and stirring or shaking them until cool.  Quick cooling is key to consistently producing a quality roast.
Home Coffee Roasting methods:
We like to recommend starting your coffee roasting adventure with an old hot air popcorn popper or a simple frying pan.  We have included detailed methods for both of these options in the back of this booklet.  Starting with a simple and inexpensive method like the popcorn popper gives you the ability to determine if coffee roasting is something that you want to do long term.  It will also give you an idea of what you would want from a coffee roaster should you decide that you want to invest in one.   Coffee roasting is something that can be as simple or as complex as you want to make it, and the roasting method is a big part of the fun.  Below you will find a brief description of the different roasting methods and the roasters that utilize them.  At our shop in Portland we have a full selection of commercially available roasters that we are more than happy to demonstrate for you.

Fluid Bed Roasting

  • Fluid bed roasting is the most common technique that home coffee roasters utilize.  This method uses a fluid bed of hot air to both heat the green coffee beans as well as agitate them.  The “popcorn popper” method is a prime example, and probably the most widely used.  Fresh Roast’s SR300 & SR500 and Hearthware’s I Roast II are examples of fluid bed coffee roasters that have been specifically designed for the home coffee roaster.  Nesco’s Coffee Bean Roaster Pro is a hybrid, it uses a fluid bed of hot air to roast the beans but it relies on an auger to keep the beans moving.


Radiant Heat Roasting

  • Radiant heat roasters rely on the coffee beans coming into contact with or passing close to a surface that has been heated.  Keeping the beans moving to assure an even roast is usually accomplished by a rotating drum.  The Gene CafeBehmor 1600, and Hot Top coffee roasters all use the radiant heat method.


Conduction Roasting

  • Roasting green coffee beans by conduction relies on the coffee beans being in contact with a surface that is hot.  Roasting your beans in a frying pan would be roasting by conduction.  This is probably one of the oldest ways to roast coffee and is very effective.  The downfall is in the quality and ability to achieve consistent results.  I highly recommend trying the “frying pan method” if for no other reason than to gain respect for modern convenience.


Coffee Roasting Process

Since many of us start our home roasting experience using a hot air popper that is the baseline I will use for explaining the roasting process.  For home roasters, especially beginners, the easiest way to judge the roasting process is by sight, sounds and smells.  As you gain experience you may choose to add the more challenging “temperature” to your roast process, but this takes some time to discuss, so I’ll save it for another time.  Once subjected to heat, the coffee beans will begin to change.  These changes are documented by the sounds and smells they emit and the visual changes that occur.  Below is a basic breakdown of the changes that occur and where along the process they occur.

After placing your beans inside the roaster and turning it on there is a period of time where no apparent changes are occurring.  At this stage the beans are being brought up to temperature and moisture is beginning to be released.  As the temperature of the beans increases the changes become more apparent and more rapid.

This video shows the entire roast process from Green to Second Crack;

Opening Stages
- Green – Light Brown
- Internal bean temperature – less than 400° F
- Beans are dry (no oil droplets present)
- Very humid hay-like smell
- Not palatable


Cinnamon Roast:
- Light brown to cinnamon color
- Beans are dry (no oil droplets present) internal bean temperature – less than 400° F
- Roast stopped before first crack is completed
- First toasted smells, toasted seeds and grains or bread
- Low body and light acidity


American Roast:
- Medium light brown color
- The beans are still dry
- Internal bean temperature – 400-415°
- This is the stage where “first crack” begins
- Aromas start to change to caramels and smoke
- Profile – The acidity brightens and body increases slightly


City Roast:
- Medium brown
- The acidity continues to increase and the body becomes more potent
- Internal bean temperature – 415-435°
- First crack stage is finished
- Profile – 50% of the sugar is caramelized, acidity is developed and the varietal character of a bean can be clearly tasted


City +:
- A more developed stage of City Roast, well beyond first crack.


Full City:
- Rich brown color
- Beans may show tiny droplets of oil
- Good balance between sweetness, body and acidity
- Internal bean temperature – 435-445°
- Just into the first snaps of second crack
- Varietal character is present with decreased acidity and slightly
bittersweet “roast taste”


Full City +:
- More developed version of Full City well into second crack.


Vienna Roast:
- Moderate dark brown color
- Beans have oil on them
- Internal bean temperature – 445-455°
- Second crack at or near completion
- Acidity muted. Cup quality is bittersweet with heavier body


French Roast (some call this Italian, some also call the next stage, Italian):
- Dark brown color
- Beans covered with oil
- Acids are radically decreased
- Internal bean temperature – 455-465°
- Subtle nuances are mostly gone. Body dominates with burnt undertones