question for i-roasters

[ackers]

If you put 150g of beans in your i-roast and programmed a profile of 160 for 10, 160 for 4, 160 for 1, what would happen. In my case I have to stop the roast at full city after about 7 1/2 to 8 minutes. Go on, take a chance on wasting 150g of beans and try it. Alan.

[AlanP]

Sounds more like a program for a bake than a roast,I don't think it would work very well on my machine.
How does it taste?









?

[ivdp]

Times seems a bit long, temp a bit low. But if your coffee is finished in about 8 minutes, what is your complain>
Next time program time span of 8 minutes and you can walk away.
Ivo

[Gouezeri]

Ivo,
The point Alan was trying to make, is that on his I-Roast, if he programs it to the lowest possible temperature for the longest amount of time, temperatures still seem to raise beyond control and he reaches a Full City style roast after 8 mins or so. It wasn't a recommendation, so much as a request for comparison. The "complaint," therefore, would be the lack of user control. As for programming 8 minutes and walking away, the programming itself would thus be pointless
D

[AlanP]

Dom's right,Alan's machine seems to running way too hot.
If he's unable to roast for longer than 7-8 mins he may as well be using a popcorn popper,I'd consider asking for a replacement or fit a probe to find out the relationship between what's being programmed and what temperatures are being reached

[ivdp]

Dom's right,Alan's machine seems to running way too hot.
If he's unable to roast for longer than 7-8 mins he may as well be using a popcorn popper,I'd consider asking for a replacement or fit a probe to find out the relationship between what's being programmed and what temperatures are being reached

Indeed, I see the point.
Maybe the machine is faulty, better check with supplier.

Ivo

[ackers]

Sorry to drop a question like that without some background, as Dom has said, no matter what I programme, the temperature (using the digital display) slowly increases until the beans are roasted. I am used to it now so I keep my eye on it and stop it at the right moment and and end up with a nice roast. Whats wrong with that you may ask, the whole point of having a programmable roaster is to be able to programme it, to play with it. If somebody else tries roasting 150g at 160 and they don't end up with roasted beans then I will be convinced that mine is faulty and send it back, or have you all convinced yourselves that your different profiles are actually working. I am not trying to be awkward but this thing is no different than my Imex was. Alan

[ackers]

An update. After convincing myself that my roaster was faulty I returned it to HB and Steve sent me a new base unit. I received it this afternonn and have done 2 roasts with different profiles. It's the same!!! At this stage I must apologise to Steve. I have been to the Hearthware web site and reread the FAQ, this is what it says:

In the beginning heating up stage, the I-Roast will have low motor RPM (low air flow) most of the time together with the highest heating power in order to reach the setting temperature as quickly as possible. And because the beans are green and cold in the beginning, they can resist the heat better than later stage. If the RPM is always at the high level, it may never be able to reach your setting temperature at a given heating power.
- Only after the setting temperature is reached, the I-Roast will kick into high RPM mode and maintain this temperature for the rest of the time in this stage. So if you have a relatively high temperature setting, you may see that it takes long time before the roaster kicks into high RPM range -- This may cause unevenness and sometimes burns on the beans. This is more often if the ambient is cold, it take longer time to reach your setting temperature.
- In order to maintain the temperature more accurately, the I-Roast not only has different modules on RPM variation, but also has the selection on heaters and heating mode.
- Please keep in mind, the motor RPM (air flow) is higher when the hot air temperature (your setting temperature) is lower, and vise versa. So you can adjust your settings accordingly to achieve the best result.

On both of my machines I have never heard an increase in fan speed except when it goes into the cool cycle. Is this programming thing just one big con, am I missing something, am I asking too much to expect it to work as advertised. I wil happily send a bag of beans to somebody if they will try 160 for 10 minutes and tell me the results.

[ackers]

Another update, I contacted Hearthware cutomer services and explained the problem, this is the reply:-

Dear Alan,

Looks like you have a European model of the I-Roast. Usually this happens when you have a higher voltage input and high power, it roasts faster.

One way is to roast outside, where is cooler, it will reduce the speed.

Another way will be changing the temperature setting: if you open up the bottom cover of the power base (3 screws), and you can see an opening with part of the PCB board exposed, there is temperature setting jumper (a resistor with white plastic plug, ~10 mm size) inserted on the board, You can pull it straight upwards, and the jumper will be removed from the socket. The resistor value should be between 1.0K-ohm to 5.0 K ohm, the higher the resistance, the lower the temperature setting.
So if the roster is roasting too fast, replace the resistor with a higher value one, such as 4.5 K-ohm, it will slow down the process. and vise versa.

Thanks!

Ron Liu

Any comments.

[phil]

I've been holding off mentioning this Alan, but since Steve mentioned it in conversation to me recently and now you've posted the above I don't feel too much like a broken record.

What's your supply voltage?

[simonp]

Another update, I contacted Hearthware cutomer services and explained the problem, this is the reply:-



Looks like you have a European model of the I-Roast. Usually this happens when you have a higher voltage input and high power, it roasts faster.

I don't understand this, if the I-roast monitors it's input air temperature then surely the input voltage (within reason) doesn't matter as it can just lower the heat.
It sounds to me like it does not monitor the input temp, and just sets a heating level without feeding back the measured temperature, which seems crazy to me.
Has anyone asked HW why the input voltage should have an effect?

[ackers]

I've just checked my voltage at 244v, the rating plate on the roaster is for 230v but I agree with Simonp and would not have thought that it would have made any difference. Has anybody experienced the variation in fan speed to control the temperature?

[phil]

If the control mechanism were perfect, maybe. It won't be. There'll be some hysteresis surely?

Wlodek, where are you?

[ackers]

I think I will buy a driver to fit the security screws on the base and have a look to see what size resistor is fitted and adjust if necessary. My priority is to get it working as it should and then try and work out why it didn't.

[Gouezeri]

Hi Guys,
I know I've been quiet on this (whereas I've been fairly vocal previously), but I'm busy running a series of tests myself and I don't really want to comment in detail until I've had the chance to try things out fully and assess my results.

have done 2 roasts with different profiles. It's the same!!!

Please take this as me trying to be helpful Alan. Simply saying that 2 different "roasts" (beans? attempts?) with 2 different profiles (times? temperatures? sample weights?) were the same, is not providing us with enough information to be able to comment, or be of any help. In my personal experience, I have had quite a few (intended) different results using different sample weights, different times, different temperatures. If I have got any beans left from all the tests I'm running, I will definitely try your 165 for 15 minutes though.

On both of my machines I have never heard an increase in fan speed except when it goes into the cool cycle.

I must disagree here. Can you hear a difference in fan speed? No. Can you see a difference? Yes, definitely. Try this for yourself, use either of the 2 preset profiles, set the machine going and watch the movement of the beans at the very start. In all likelihood they will just flow slowly. After five minutes, look again, are they flowing in the same way, or are they now moving much faster and bouncing around a little? Unless it's the infamous doosers at work, that's the result of the fan turning at higher revs.
Finally, I also wonder the degree to which ambient temperature may have an effect on your results.
If you like, I have a roast chart that I have been using to keep a record of all of my results (this is the only reliable way for accurate comparison) and I'd be happy to send you a copy that you could print off which would allow us to compare information much more productively.
As soon as I've had the chance to run enough tests with my thermocouple and different sample weights, I'll provide whatever findings I have here for everyone else to comment.
Dom