How To Roast Coffee
As an American transplant in New Zealand I have noticed that the way they serve coffee here is almost exclusively as espresso. I do not like espresso as I cannot do it well at home without a pretty great expense. I also have always been a fan of darker roasts which you simply cannot find here.
So I decided to make my own. Here is a guide that you can follow if you want to do the same.
Choosing Your Beans
So you’ve decided to roast your own coffee but how do you choose the right beans? This will depend on what kind of roast you are after. This can get out of hand very quickly because there are a number of factors to consider. For example:
- Bean varietal
- Drying method
- Washing method
- Country of origin
- Grown in Shade
As you can see you can descend down the rabbit hole very quickly when it comes to coffee. It is very much like wine in that respect. Each bean growing region will produce a distinct flavor profile based on the factors I listed above.
Since this is your first time let us keep it simple. Below I have laid out what kind of beans take what kind of roast well. This is a rough guideline but it should get you going on your first roast.
As a general note: the darker the roast the less you will be able to taste the unique notes of the origin of the coffee and the bean will begin to taste like the roasting process. This will result in your coffee having an almost dark chocolate taste and a bold body. Also, acidity and caffeine decrease as the level of the roast increases.
In terms of how to pick suitable beans for your roast here is a general guideline which I have observed through A LOT of coffee drinking:
Again, this is a very general guideline. It is just there to help you to quickly pick a varietal based on your preference for the darkness of the roast.
Roasting Your Beans
So with that sorted let’s get down to the actual process of roasting the coffee. I will walk you through roasting in your oven but there are some really fancy coffee roasters out there. If you are ready to make the leap, head over to Amazon and look at a couple.
- Preheat your oven to 260OC/500OF Once it reaches that temperature let it sit there for 30 minutes. This will prevent the temperature from dropping quickly as you open the oven later in the process.
- Measure out 150g of green coffee beans. Do this precisely. If you are starting to take your coffee seriously I recommend ponying up and buying a Hario Drip Scale over on Amazon
- Take out a perforated baking sheet. I could not find one in New Zealand so I bought a perforated pie tin. If you have access to Amazon you can buy a baking sheet there
- Spread the beans out into one layer. If you have more room than I do leave about 1 inch between the edge of the sheet and your beans
- Put your beans on the oven and keep an eye on them. They will begin to yellow somewhere between 3-4 minutes. When this happens stir the beans to move some of the beans on the outside into the middle
- Now it is time to listen. Your beans are being transformed and, much like popcorn, will pop once they reach a certain temperature. This is called the first crack and it will happen sometime between 7-9 minutes. Once you hear this wait for 45 seconds then give the beans another stir
- This is when things start to change fast and you need to keep a constant watch over your beans. The best marker for your desired roast is just to get your eyes on the beans to gauge their color. Take them out just before you think they’re done as they will continue to roast once out of the oven
- If you are going for a dark roast you need to wait and listen for the second crack. On my last roast my beans went through their first crack at 7:30 and the second crack at 11:00 minutes. I let them go for another minute before pulling them out of the oven
- After the second crack the beans move even faster towards a dark roast. So unless you like your coffee to be REALLY dark I wouldn’t keep them in there for too much longer
- It’s time to cool the beans and remove the chaff. Do this by pouring the beans between two strainers (I used two colanders) for a few minutes, until the beans can be handled with bare hands. It is important to do this outside as chaff from the beans will go all over your kitchen otherwise
- Measure the weight difference. Subtract the end weight of the beans from the starting weight then divide by the starting weight. The percentage you get will be the amount of water lost in the process (granting you didn’t spill beans all over the ground). This is a good indicator of the level of roast that you have reached
- You’re done! Some people recommend waiting a seven days from roasting to drink your coffee others say it is OK to drink the very next day. It depends on how excited you are to drink it! Below is a picture of my coffee after seven days and you can see how the oil has come out of the beans and coated them.
In the meantime find a good place to store your beans. I recommend heading to Amazon to buy a Friis Coffee Vault as they let your beans vent CO2 without letting any air back into the container.