I-burn Help?

[JamesP]

Hi Guys,

I am really struggling with my I-Roast 2, I am trying to roast about 75g (1 spoonfull of the supplied cup)

I have tried about 6 roasts and whatever I do the beans come out the same, fairly darkish.

I am roasting Brazil Cachoeira Canario Dried on Screen 2007-2008 from HB.

I have finally settled on the following profile but is is still too darK:

160 - 3 mins
186 - 2 mins
210 - 2 mins

I am getting the 1st crack at 3:34 remaining and the 2nd crack at 30 seconds remaining

This is not a long profile nor a really hot one, I dont understand why it is coming out so dark.

One thing I have noticed is that on the 160c setting it usually reads the temp as ~207c but when it steps up to over 200c it reads it as about +10c over the setting, is this normal? the fan does seem to step up and down ok andmost of the time on this profile it is on low

Any help/pointers would be much appreciated!

[Gouezeri]

Try 130-140g for a start and measure by weight not volume. The IR is not configured for roasting such a small batch. Ignore the onboard temperature. If you want accurate temperature readings, try a thermocouple.

[JamesP]

Ok I will give that a try

I just didnt want to ruin too much decent coffee

[JamesP]

Does that profile look the right way to go for this bean?

[Gouezeri]

Hard to say without knowing other variables such as line voltage. I'm also unsure as to what other changes have been made to an IR2. If it compares to an un-modded IR1, then that would seem a little fast. It also depends on what beans you're roasting and what you consider to be "dark" (waits for Steve to pop up and moan about roast pictorials ). I think you'll find there is plenty of info on the I-Roast here, so have a bit of a search, try some things and then ask whatever questions arise.

[JamesP]

I have done some more reading and I am fairly sure I need to do the resistor mod.

Can someone point me in the direction of the instruction sheet or email it to me?

[Gouezeri]

Don't know if mine are the only instructions out there? Would have thought that somebody else might have written something as well. If not, PM me an email address and I'll sent it on.
Please note that this will slow things down, but it still won't make the IR follow precise profiles, but rather "trends"

[JamesP]

PM sent

I have been doing a bit of reading, my voltage is 241V, I think I am going to have to try a few resistors from 1.8kOhm to 2.8kOhm

I could really use a thermo couple!

[Gouezeri]

Email on its way. I really should have charged for this from the beginning as I could have bought a hottop the number of times I've sent it out now
Installing a thermocouple isn't tricky, just a matter of buying an appropriate digital MM and enlargening a hole in both the lid and the chaff ring, then threading the thermocouple down into the roasting pot. The aim is for it to "float" in the bean mass and not come into contact with the pot.
As ever, yell if you need a hand, though be quick as I'm putting up my prices

[JamesP]

Excellent you are a star thanks

Mabe it should be put in the download section?

[Gouezeri]

True. Though I prefer the more personal side of things, if anybody has any questions then it is easy for them to give me a shout and am slightly wary of recommending anything publicly which is likely to invalidate warranties and could cause potential damage. There aren't that many sources on the net for the I-Roast, so people normally come asking questions when they are ready.

[Syber]

Hi James,
I have an Iroast2.
I agree with gouezeri; these timings are a bit on the short side.
Is the heat getting out properly?
I had a ethiopian Yirgaffe (or whatever) that really filled the chafcollector with a dense layer of small pieces chaf ..

[JamesP]

I bought all the bits to do the mod, including a theremocouple but I tried a roast with 4oz of beans and I found it was a lot better!

The temp shown by the thermocouple in the beans was about +/- 10'c of what was programmed so thats a result!

The onboard temp display was wildly out though!

So looks like my problem is solved!

Thanks for all the help

[Gouezeri]

Cool. Glad you're sorted.
D

[Egholm]

Hi JamesP,

I bought all the bits to do the mod, including a theremocouple but I tried a roast with 4oz of beans and I found it was a lot better!

A bit OT: What thermocouple did you get? I've been searching for a cheap one in Europe, but cannot seem to find any...

The temp shown by the thermocouple in the beans was about +/- 10'c of what was programmed so thats a result!

The onboard temp display was wildly out though!

So looks like my problem is solved!

Yes, I mod'ed mine with a potentiometer so I could easily find a suitable value. I ended up with 3k3.

I've attached a general mod-picture for future reference for others.

BR,
Egholm