There is no reason not to roast your own coffee. It is quite easy to roast coffee, and there are lots of shops also online, where you can buy the fresh green coffee beans, ready for roasting. Maybe you didn't know, but coffee beans are green before they are roasted.
With fresh green coffee beans, the coffee quality is always best
The price for top notch unroasted coffee beans is comparable to the roasted discount coffee you get at the supermarket. On top of that the shops that sell unroasted coffee beans only sell the top 2% best coffee beans from all over the world. In other words, the quality is magnificent when you choose to roast your own coffee. You get pure single estate arabica coffee at a good price, when you buy the green coffee beans.
Roasting coffee in gas or convection oven is easy
You don't need specialized equipment to roast your own coffee at home. All you need is a baking pan, and an oven that heats to 220º-250º celsius.
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Things you need to roast coffee at home |
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Oven Baking pan Green coffee beans
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It is handy to have an extra baking pan ready for the warm coffee beans too cool off in, when you have finished the coffee roasting.
It is often recommended to use a baking pan that has been perforated with small holes placed close together. Usually a round pizza pan with air holes in the bottoms kan be found at kitchen supply stores, or you can drill the holes in your own personal coffee baking pan - if you get bitten by coffee roasting. The wholes will give a good airflow around the beans securing a more even roast. A regular baking pan, with a raised lip, will work fine though.
First step - turn on the oven
Turn on the oven. It needs to be set at 220-250 degrees celcius. Low temperature gives a longer roasting time, allowing the beans to build up some caramel flavour. Higher roasting temperatures gives a shorter roasting time, but ensures a proper roast. Different coffee beans have variable optimal roasting times. Experiment to get the best results with the coffee beans of your choice.
Regular supermarket coffee is roasted on industrial sized roasters. On these the coffee is roasted for 3-5 minutes at temperatures up to 500 degrees celsius! Obvioulsy, roasting can be varied quite a bit, when it comes to roasting temperatues. The most important thing is, that the temperature must not be too low, otherwise the coffee beans will get cooked, not roasted.
The oven must have the desired roasting temperature, before putting the coffee beans inside. A home coffee roasting in the oven usually takes 9-15 minutes.
Second step - place the green coffee beans on the baking pan
Pour the green coffee beans onto the baking pan, and make sure there is only one layer of beans. Coffee beans expand quite a bit under roasting, and it is important that they don't get on top of each other.
Third step - roasting the coffee
Actually coffee beans pop just like popcorn. The pop is not with the same violent force, though. The coffee beans just crack, when the oil inside them heats up. This produces a popping sound, and maybe a little jump from each coffee bean.
You need to watch and listen for this pop. Coffee beans crack twice. The coffee's first crack and second crack tells us when the coffee roast is finished, so we need to keep an eye on the coffee while roasting.
Fourth step - look and listen for the first crack of the coffee beans
When the baking pan with the green coffee beans have put in the oven, the coffee beans will quickly change colour from green to a beautiful golden colour.
After a while, typically 6-8 minutes, in the pre-heated oven, the first pop (crack) will appear. Some of the coffee beans jump, and you will be able to hear the beans crack.
In the principle the coffee is drinkable after the first crack. The short roasting time (and low coffee bean core temperature) gives the coffee a fruity but sour taste, and a lot of the original fruit flavour of the fresh coffee bean. A very light roast can be a bit special to drink, especially if you are new to roasting coffee. But it can be put to good use in coffee blends, with different kinds of beans and roasts. As a novice roaster, it is most likely that you will want to roast your coffee quite a bit darker.
Fifth step - look and listen for the more subtle second crack of the coffee beans
The second crack usually comes 1-4 minutes after the first crack. If the temperature is too low, the second crack might never appear. The heat determines if enough pressure is built up in the beans for the second crack to appear.
The second crack can be a bit harder to hear and see. The sound is more subtle. At the point of the second crack, the coffee beans will have a nice dark brown colour. Shortly after the second crack, the coffee will start to acquire a burnt flavour. So keep an eye on the beans at this point. Many people prefer to stop the roasting just before the second crack, or just 15-30 seconds after the second crack has started. At this point it is likely that the coffee has reached a well balanced roast. Usually you will aim for some caramel sweetnes and roundness to the flavour, while preserving some of the fruity character of the coffee bean.
Observe that different coffee beans have different characteristics. Optimal roasting time and temperature varies. Getting the best out of the coffee is all about experimenting.
Sixth step - let the coffee cool off
Be advised that roasting coffee emits a bit of smoke. When you roast coffee inside, you need to vent out the smoke. Open a window before opening the oven.
You need to cool the coffee beans right after they are taken out of the oven. There will still be quite a bit of residual heat inside the beans, so put them out onto a flat surface (a second cold baking pan) or vent them by putting the back and forth between two containers.
The coffee should now have attained a dark chocolate colour. You will also notice left over chaff from the coffee beans. The chaff is blown away from coffee beans that you buy roasted. However you do not need to remove the chaff. It tastes just like the coffee beans, and can be put in the coffee grinder along with the beans just fine.
Seventh step - give the coffee a rest
The coffee will taste better after resting for 20-24 hours. But if you just finished your first attempt at roasting, brewing a cup of coffee right away is fine. Just know, that the coffee will build up more body and taste if it is allowed to rest for a day.
Eighth step - enjoy a good cup of coffee
Make a good cup of coffee, as you prefer it. As espresso you want to use a fairly dark roast and maybe even mix in 10% robusta type coffee beans. Filter coffee is made just the way you usually do it.
Pre-heating your coffee cup will preserve the good taste of the coffee even better.If coffee is quickly cooled against the surface of a cold cup, it might acquire a tiny bit of bitterness.
You are now ready to experience a coffee, of the highest quality available.
Does home roasted coffee get too old?
A week after the roasting, the beans will start losing some of their flavour. 14 days after coffee has been roasted, the oils in the coffee starts to get harsh. You will get the best coffee taste if you drink the coffee within the first two weeks after roasting the coffee. Roasted coffee from the supermarket kan be months to years old when you buy it. That is why the coffee you are used to often has a bit of a harsh taste, which will become very apparent when you have tried your own home roasted coffee.
The real good taste of coffee is only for those who roast their own coffee. When you have been drinking your own rast for a week, you will start wondering why you didn't always roast your coffee yourself.
Welcome to the coffee roaster's club!