Coffee information from The Coffee Brew.

Coffee Roasting Basics….here’s what you need to know.

Making your own home brew, whether it is wine, beer or spirits does not always guarantee the best result of a good tasting drink.

However coffee lovers will be pleased to know that roasting fresh green coffee beans at home is much easier – just a little experience, the right equipment and your results will be as good as the pros.


With a little bit of research you’ll find a variety of roaster appliances are available and that they vary in size, style and design. It is just a matter of finding what best suits your own family needs. You can even use a frying pan or popcorn popper but be very sure to start with super clean equipment. Nothing will spoil the taste of a freshly roasted batch of coffee more than a hint of the last garlic prawn dish you cooked in the frypan.

The main thing with roasting is to start with the best quality green beans available. Dark roasts contain a little less caffeine than lighter roasts, but they lack the acid taste of the latter so with a little trial and error you will soon find the perfect degree of roast for your beans.

When roasting, the beans will need to heat to between 460F (223C) and 530F (262C). That’s pretty hot so be prepared for some smoke. This can be taken care of pretty easily with a small room fan or stove top exhaust. Apart from the smoke there will be a strong burnt coffee aroma, so your first experiments are best done with all the windows and doors open. If you have a suitable covered outdoors area then this may be the best place to start your coffee roasting career.

So, now put the beans in the roaster and turn up the heat! And here’s a good tip, be ready to temporarily disable those over-sensitive home fire alarms.

With some coffee roasting appliances the thermometer is built-in, but you may need to buy a spare one for those frying pan experiments. Candy making thermometers work well so maybe you could grab one of those.

During the roasting process the green beans will turn yellow, then brown. How brown depends on how dark you like your roast. This is an individual choice so you will have to test drive the odd cup of coffee until you come up with a brew whose acidity and flavour suit your own personal taste.

As the beans begin to heat up, moisture - both oil and water - will put pressure on the bean surface and you may hear a loud crack when it bursts. Don’t get excited - this is normal and all part of the process. Stirring every 30 seconds or more, you'll begin to hear these bangs after four to seven minutes of heating.

What happens during roasting process is the sugars inside the once green beans will begin to caramelize, turn brown and burn slightly. Again the degree of dark roast is purely a matter of personal taste. Just make sure to check the color every 30 seconds or so.

One way to tell if the roast has gone on for long enough is sometimes a second loud crack will occur. At this stage the beans will be quite dark and black looking in colour and for some palates will be a little overdone. Go beyond the second crack and you're really just burning the beans and boiling away the sugars. The results will be too harsh for most people to stomach.

Now you are nearly done. Pour the roasted beans into a metal colander to cool and then gently agitate. The roasting process produces chaff. This is a fine skin that detaches from the bean as you agitate them. You will need to devise a method for removing it. One idea that works well for me is one of those mesh type cooking screens.

The trick is to experiment with a few small samples of green beans using varying degrees of time or darkening until you get the flavor you prefer. Also bear in mind that the heat trapped in the bean will continue to cook it for a short while, so try stopping a little short of your desired degree of roasting. Keep track of the time taken for each batch and match this up with your taste test – then you will know which the perfectly roasted bean is for you.

Here are a couple of other quick ideas - popcorn popper style roasting. Be sure to get a machine that allows you to stir up the beans to keep them moving around and not sticking to the surfaces.

If you want to try the stove top method, a cast iron skillet is a good choice. But be prepared for lots of stirring and pay close attention to the degree of roast that is going on.

Roasting coffee beans happens pretty quickly!


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