Roasting coffee beans can be a very satisfying experience. There are many ways and techniques to roast coffee home. A truly enjoyable activity, and the guarantee that your cup of coffee will always have the exact profile, unique to your taste.
Nothing better than freshly roasted coffee
There isn´t a better coffee, than freshly roasted coffee. It brings all the health benefits, and a full flavour experience. Unroasted coffee (it’s called green coffee) lasts for a long time. Stored under mild temperatures and in a controlled humidity environment, green coffee can last for years without losing quality.
However, after the coffee bean is roasted the situation is completely different. Roasted coffee is a complex product which reacts quickly with the air. Oxidation – the chemical reaction of a compound gaining oxygen –happens quickly on roasted coffee, and changes the flavour profile, and the chemical components of the coffee.
Caffeine, one of the main components in coffee, is stable and does not oxidate. However, several complex compounds on roasted coffee, chlorogenic acids, are volatile and the oxidation process starts immediately after roasting. Several studies about the benefit of coffee to your health show that fresh coffee brings much more benefits. As you drink old coffee the benefit of caffeine remains, but all the antioxidants compounds disappear.
There isn´t a precise time before your roasted bean becomes stale, but as rule of thumb use your roasted beans, (grinding only on the moment of preparation), 24 hours after roasting, and never with more than 10 days after roasting. Therefore, here is an important tip: roast your coffee on small batches, never more than one week consumption. If you follow this advice, you will have a great experience on every cup of coffee.
The roast process is, simply said, to use heat to turn green coffee beans into brown roasted coffee. You can roast in your oven, a popcorn popper, a skillet or buy a home coffee roasting appliance. Depending on the roasting method the challenge is to achieve a uniform roast. Whatever method you use, you will be on your way to drinking much better coffee.
Roasting times vary, depending on the method, the heat, and batch size, but you can expect the process to last from 6 to 16 minutes (for larger batches). If you are a beginner, whatever the method you use, start roasting small quantities. We suggest 8 Oz or less. Trial and error are the best advice until you master the uniform roast with the roast degree you want.
There are several ways you can home roast. You can use a stovetop or a hot air popcorn popper, or a specific appliance for coffee roasting. There are several different models, with prices ranging from a few dollars to a few thousands.
From the Coffee Chronicle they briefly describe three basic ways to home roast your coffee:
In the oven: This is the easiest way to get started since you don’t need any additional equipment. Some ovens tend to cook a bit uneven, but you can still get good results by stirring the beans constantly. Preheat the oven to around 215°C/420°F on hot air mode. Pour beans on a heating plate (preferably perforated) and keep a close eye on them. Stir them around once in a while. Finish the roast after the first crack has been rolling for one to two minutes.
In a popcorn machine: This method is prevalent because it’s both reliable, cheap and cheerful. The air will circulate the beans while cooking them and creating a good even roast. This method is rapid though; sometimes you’ll have coffee ready in just 4-5 minutes. The main downside is that the coffee can get burnt quite easily or that your machine can overheat and shut down. Also, the capacity tends to be quite small at around 100 grams at a time.
On a home coffee roaster: If you enjoy roasting coffee at home either in the oven or with a popcorn machine, chances are that you’ll eventually want to upgrade to a home coffee roaster. With a dedicated tool, you’ll have much more control over small changes in temperature, and you’ll be able to create roasts that match your local coffee shop. Often a tiny coffee roaster will pay for itself in the first year just from the savings you make on green coffee vs. roasted.
If you want to read further about home roasters available click here, for another post from the coffee chronicler.
Depending on the combination of heat source, time, local temperature, humidity, and the coffee you are roasting you may achieve different roast levels.
Which roast level is the best? The one you prefer. There is a basic suggestion for a roasting degree depending on the method you will brew your coffee.
We tend to prefer light roastings; it usually brings the more subtle flavour from your coffee. But this is what home roasting is all about: you can have your coffee exactly the way you prefer, and whenever you want, you can try it differently.
This table show the usual denomination of roast levels. You may keep a record of all your roastings comparing with this colour table, and your assessment of the flavours it produces.
“First crack” and “second crack,”:This comes from two different moments of chemical reactions during the roasting process. An audible popping sound is heard during roasting in two different moments. The first is an audible cracking sound as the real roasting starts to occur. As sugars begin to caramelize, the bean breaks down and oils pop out. The second crack happens usually after the coffee reach a full city colour.
The expert roaster
If you are an expert roaster, we would love to hear your comments and techniques. How do you roast your coffee? What is you preferred roasting curve, with temperatures and roasting times?Any additional tips are welcome.
Please leave your comments here, and help others to follow your coffee roasting method.
Thank you for sharing your knowledge.