Roasting my own Coffee



I started roasting my own green coffee beans this year with the belief that I will get the freshest coffee beans all the time. It was not as simple as I initially thought, but it was a great learning journey figuring out how to roast my own coffee.

I have always been a coffee drinker . I probably started drinking coffee when I was about 4 or 5 years old. The taste and aroma appealed to me right from the beginning. I learned to make sock coffee watching my mother and as I got older, I progressed into getting a coffee drip machine using packaged ground coffee. I discovered that freshly ground beans gave the best tasting cup of coffee, so I again upgraded from pre-packaged ground coffee to freshly home ground coffee. After using a small Braun coffee chopping grinder for a couple of years, I upgraded to an expensive Braun burr grinder and I swore by freshly burr ground coffee for almost a decade.  A few years back I heard that folks in the United States are using  air pop corn roasters to roast green coffee with some success. It piqued my interest in roasting my own coffee. It was hard to get green coffee beans in Singapore several years back on small amounts so I shelved the idea. Recently I discovered many sources of green coffee beans on sale and online in Singapore. I managed to get a reliable source and started my Green coffee roasting adventure.


I have a 20 liter toaster oven at home, large enough to roast a large batch. I got myself a rotisserie wire basket online.


My first attempt ended with coffee that was slightly under roasted. It was okay but not great. In my research, I began to understand the different temperatures the coffee bean goes through during the roasting process.


My set up was not as professional as dedicated coffee roasting machines, but through experimentation and with different coffees from Colombian, Guatamalan, Ethiopian, Indonesian Java and Sumatran Mandheling and even Burmese coffee, I developed my own roasting method. I used to monitor my temperatures closely with a temperature probe but I found the best way to monitor the roast is to look at the colour of beans as it is being roasted. Look for the smoke and especially LISTEN to the cracks. If the beans does not produce any cracking sounds, then they will be most likely under roasted; which still produces a decent cup but perhaps with a more fruity and less “toasted” taste. I like my coffee dark but not too dark so I go for a city roast plus. I have roasted coffee way pass City Roast before and after resting the coffee, they produce way too much oil. Now I try to keep it between City and City plus roast. This produces the nice balance of taste and fragrance without the oily beans clogging my SAECO All-in-one espresso machine’s burr grinder.

Here’s how I do it – IMG_20171008_153615

Coffee Cracking during roast

In the above, Indonesian Java or Mandheling coffee is being roasted and producing the 1st cracking sounds after around 25 minutes from a cold toaster oven without pre-heating. The oven is equipped with the rotating roasting wire basket with metal spoons and scoop added to agitate the beans during roasting. Maximum temperature setting was used on the toaster oven at 250C. Mechanical timer was set to 30 minutes but roast was stopped before that, probably around 25 minutes. In the past I used to pre-heat the oven, but I found it was not necessary. Aluminium foil was used to reflect heat back from the clear tempered glass door. A small hole was cut to observe the roasting colour of the coffee beans. A powerful white LED light was used to shine into the observation hole. Roasted coffee in the wire basket was removed with thick oven gloves and agitated to remove the coffee silver skin or parchment. Then beans are emptied into a large Ikea mixing steel bowl and stirred with a wire egg beater against a fan to cool down. The freshly roasted coffee beans was then stored in a single way valve container to allow the Carbon Dioxide to escape. Coffee reached maximum fragrance on the 2nd or 3rd day and ready to grind and brew.

Through this experience I now have possibly the freshest coffee I can enjoy. For those of you who live in Singapore and want to get a reliable supply of Green coffee beans, I highly recommend – Blendnew Coffee



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