The iRoast2 - Initial Experimentation

Default Profiles

iRoast 2iRoast 2

As per recommendations, for my first attempt at roasting beans in the Hearthware iRoast 2 I used the default 1 roasting profile. This turned out to be too dark a roast for my palate, certainly for daily use. For the next roast I used the default 2 roasting profile. This also turned out to be too dark for my palate.

Custom Profiles

Swimming around in a sea of self-doubt I consulted forums on the Internet to see if any coffee roasting Guru could pass me some words of wisdom. Fortunately, and no less than I would have expected, I came across someone who had taken the time to review the iRoast 2. He also provided advice about roasting and a startling roasting profile which I could use.

Custom Profile 1

My next step was to discover how to set up and programme a roasting profile for the machine. This turned out not to be too complicated and and so my first personalised roasting profile was entered into the roasting machine and stored for future use. This roasting profile which was a copy of the profile suggested on the Internet in the review, consisted of five stages which took 15 minutes of roasting time. The profile was set at 168°C for four minutes, 174°C for four minutes, 184°C for three minutes, 180°C for two minutes, and 192°C for two minutes.

Using this roasting profile with Ethiopia Wild Bonga Forest green beans from Has Bean, provided me with coffee just as I had hoped. The taste was complex, unusual, fairly light and bright, and always with a taste which stimulates discussion and interest. I thought I had mastered the process. Subsequent roastings of other coffees however proved me wrong. Too light, too dark, loss of complexity plus a variety of other complaints made me realise that I had been lucky and that further experimentation was necessary. It was not going to be possible to create a single profile which would work for me for all coffees.

Custom Profile 2

Having over-roasted a sample of coffee using my standard profile I decided to create a second custom profile. The profile was set at 168°C for three minutes, 174°C for three minutes, 184°C for three minutes, 180°C for two minutes, and 192°C for two minutes. Although the temperature settings are quite precise in this profile the actual temperatures measured during roasting turned out to be 209°C instead of 168°C, 211°C instead of 174°C, 213°C instead of 184°C, 215°C instead of 180°C and 221°C instead of 192°C. With this profile I was able to successfully roast coffee to suit my palate where previously I had roasted it to too dark a stage.

Custom Profile 3

Two profiles quickly became three when I discovered that Bolivia Cafe David Santiago Mamani Mamani Cup of Excellence 2010 green beans from Has Bean had been too lightly roasted by me. The next custom profile developed then added one minute to the process over profile 2 as follows. The profile was set at 168°C for three minutes, 174°C for four minutes, 184°C for three minutes, 180°C for two minutes, and 192°C for two minutes. A total of 14 minutes. I then applied that to Ethiopia Yirgacheff green beans from Has Bean and much to my dismay it turned out to dark.

When I say that it was too dark I mean that I would not enjoy having that particular coffee roasted to that level of darkness for daily drinking. I feel when it is that dark I lose the complexity of the taste and so identification of the coffee is more difficult. In fact the roast did provide an enjoyable drink. It was the sort of drink that one might expect to get from Starbucks or from a high-street coffee shop but that is not the type of coffee I would like to drink every day. My conclusion then is that Ethiopia Yirgacheff green beans from Has Bean requires a 13 minute roast or perhaps less when using the same type of initial roasting temperatures. Experimentation will go on with the Ethiopia Yirgacheff.

Factors Affecting the Roasting Processs

Browsing through the Internet forums can be very illuminating and I quickly realised that many other factors could influence a coffee roast. The issue of mains voltage was raised and of course that is a very obvious variable over which we have little control. I have now started to measure the mains voltage prior to starting a roast so that I can more fully understand what is happening during the roasting process. It would appear that the mains in my area is generally in the area of 245 V to 249 V. If roasting profiles are based on a voltage of let's see 230 V then clearly there is going to be a difference in the outcome when the mains voltage is 250 V.

Having undertaken investigations over a couple of weeks it appears to me that the normal fluctuations in the mains voltage in my house makes little or no difference to the outcome of my coffee roasting. With respect to the iRoast 2 this is no more than would be expected as it is a temperature controlled system.