My coffee passion from Nantucket

Roasting coffee at home: the complete guide

One of the best ways to expect fresh coffee is to grill it yourself, and when you roast coffee at home, you make sure that every cup of coffee you make is fresh and, with a little practice, you can make sure it is roasted exactly to your taste.

Although you can always go to the local coffee shop or roaster and find this type of coffee, why not roast it yourself so you can start creating great cups of coffee at home?

To roast coffee at home, you will need a few utensils and a source of green coffee, and it is also important to understand the process from start to finish to better determine how your roasting can impact the flavours of your coffee.


What is coffee and why do we roast it?

Coffee is actually a small red fruit that has to go through many steps before reaching your cup every morning.

First, the coffee is treated to remove the outer skin, pulp and skin from the inner core, and once this operation is complete, the inner seed, also called the coffee bean, is dried.

When it is dried, it becomes the green coffee bean that is shipped worldwide for roasting.

The coffee bean looks like a dry pinto bean, which means it can be stored for long periods of time and remains fresh once the roasting process is complete.

If you didn’t grill the beans, the drink would be bitter and very acidic, making it almost non-drinkable, and roasting gives the coffee its unique flavours and aromas.


What happens during the coffee roasting process?

Green coffee changes dramatically during the roasting process: when you roast coffee, moisture is expelled from the bean, causing it to dry and expand.

During the process, some natural sugars are converted to CO2 while others are caramelized to form the complex aromas of coffee, and once the process is complete, the green bean will turn into a brown bean, about 18% lighter and 50 to 100% larger.

As soon as the roasting process is completed, the coffee begins to “degas” and in just a week or two, the roasted coffee has already started to lose its flavour and aroma.


What are the different roasting colours?

Coffee beans are differentiated by 5 roasting colours: very light, light, medium, dark, very dark. Which one is right for you?

Here are the specific taste characteristics of each one (a little more reading and you can taste the coffee that suits you with full knowledge of the facts).

1. Very clear roasting

  • Very light blond colour (8/10 min of roasting)
  • Light coffee, fruity and/or floral notes
  • Typicality of the respected terroir (a Moka Yrgacheffe, for example, will have floral notes typical of its terroir)
  • Bright acidity.

2. Clear roasting

  • Light blond colour (10/13 min of roasting)
  • Sweet and balanced coffee, fruity, floral, gourmet or spicy notes
  • Typicality of the terroir preserved but slightly reworked by the roasters for a versatile use (in filter and espresso)
  • Peak acidity (depending on the coffee).

3. Intermediate or medium roasting

  • Brown colour (13/16 min roasting time)
  • Balanced coffee, beautiful roundness, developed sweetnessTypicity of
    the terroir blurred to further highlight the body, aromas and length in the mouth
  • Very low acidity.

4. Dark roasting

  • Dark brown colour (20/25 min of roasting)
  • Full-bodied coffee, slightly toasted notes
  • No acidity
  • A hint of bitterness.

5. Very dark roasting

  • Black colour (25/30 min of roasting)
  • Strong coffee, grilled/smoked notes
  • Strong bitterness
  • Persistent aftertaste.

How to roast coffee beans with a roaster?

You will need some supplies to make the roasting a success:

  1. Green coffee – Depending on where you live, this may be the most difficult task. Ask local coffee shops or look for roasters in your area who sell unroasted coffee beans.
  2. Roaster – There are different types of roasters and even a simple popcorn machine or frying pan can do the job. Below are some of the methods and types of roasters to use. You can also buy these different utensils on a second-hand basis.
  3. Storage location – Once you have roasted your coffee, you will need a place to store it until you use it. Remember, the tighter the container, the better. But even the best can will not prevent the coffee from losing its flavour and aroma after about a week if it is not used.

Now that you have everything you need to roast, it’s time to start, remember that for the roasting process to be successful, the beans must be heated to temperatures between 190 degrees C and 285 degrees C.

When cooking, make sure that the grains stay in constant motion so that none of them are burned.

You should also know that the roasting process produces a lot of smoke, so make sure that the room in which you are roasting is well ventilated or your house will quickly become very smoky.

Follow these steps:

  1. Place the right amount of coffee in the roaster and consult your manual to determine the optimal amount.
  2. Close the roaster and turn it on.
  3. Let the coffee roast until the desired colour is reached, remember, the more you cook the coffee, the darker and stronger it will become.
  4. Pour the coffee into a colander and stir until it is warm.
  5. Store coffee in a dry place at room temperature, away from light.

How to roast coffee beans with a popcorn popper?

What you will need

  • A popcorn popper
  • An external burner (gas or electric)
  • Unroasted coffee beans
  • A laser thermometer (optional)
  • A baking sheet
  • An airtight container

1. Configuration and preheating

With the grains acquired, clear the picnic table and install your burner, popper and baking sheet, preheat the popper until it reaches about 200 degrees.

A laser thermometer is the best way to measure the temperature, but it is usually enough to preheat between 5 and 10 minutes to reach the right temperature.

2. Adding coffee beans

Once the popper is at the right temperature, add the green grains and turn the crank handle, you will need to keep these grains moving all the time so they can roast evenly, so stir from beginning to end with a steady rhythm, remember that this is a job of love.

As you roast, the heat brings the beans through the roasting stages, and you can see how they change from their green bean state to their larger and darker state gradually.

Be careful, because the difference between perfectly roasted and perfectly missed is only a matter of minutes.

3. Roasting of the beans

As the beans roast, they go through several stages, so you can see the slow evolution and decide exactly how much roasting you want.

It is important to pay attention to the process here to control the flavour of your coffee, learn to control the process and (most importantly) prevent the beans from burning.

4. Cooling system

Once you have reached the roast of your choice, throw the beans on a baking sheet, let the beans cool in the breeze of nature, sending puffs into the neighbour’s yard, and depending on the darkness of the bean, you will soon be ready for storage.

5. Storage

If the roasting colour is dark, it is recommended to give the beans a cooling time of 12 hours to allow the gases to dissipate before storage.

All that remains to be done is to grind, stir and enjoy the roast of the day, and in less than 20 minutes, from start to finish, you will enjoy an excellent roasted coffee at home.