How To Roast Your Own Coffee In 6 Simple Steps
Step 1. Buy unroasted green beans
Keep in mind when ordering that while the beans will increase in size as they're roasted, they'll also lose approximately 15-20% of their weight. Every raw bean will give you its own subtle flavour characteristics as well, so do some research on our origins to make sure you are picking something you'll like.
Step 2. Round up the equipment
You don't need to go out and buy any remotely expensive equipment to turn out small batches at home. If you don't feel like shelling out for a countertop roaster, you can mimic one almost exactly with a popcorn popper. It's a perfect tool since the objective is to heat up the beans in a confined area to temps in excess of 450 degrees—exactly what they're designed to do to corn kernels. If you don't have a popper laying around you could also use a cast iron skillet, a whirley-pop, or even a metal mixing bowl and a heat gun.
Step 3. Start roasting
The other great benefit to roasting your own beans (apart from the freshness) is that you have full control over the boldness of the flavour.
Once you've put the raw beans in your heating element, turn the heat and stir. As you watch, they'll slowly begin to change colour from green to yellow, and eventually to light brown, which is when you should listen for the "first crack", a sound vaguely similar to popcorn popping and it signals when you begin to see chaff (skin of the raw bean). If you're using the popcorn popper, the chaff should rise up and out the spout on its own, but if you're using a different heating method you can simply blow it off the top.
Step 4. Pull them out once they're dark enough
If you like your coffee incredibly light (a city roast), you'll want to quit the roasting process around this point. Like it darker? Hang on a few minutes until you reach a French roast. Just be careful not to wait until it's so black that it's essentially charcoal; it will taste terrible.
Step 5. Cool beans
Once you're happy with the roasting level, it's time to remove the beans and let them cool for a few hours. It's up to you how to do it, you can lay them out on a baking sheet or strainer. They'll be very hot, so be careful not to burn yourself.
Step 6. Let them breathe, then start the brew
Once it's nice and cool, transfer the batch to an airtight container. But don't seal the lid completely for a day or two, since it may explode as the beans slowly off-gas carbon dioxide. You'll want to wait about as long to grind and brew them as well and use them within the five subsequent days for ultimate freshness.