IRoast Roasting Profiles??

[TimA]

Re: IRoast Roasting Profiles??

How many roasts have you done Tim?  6 minutes is lightening I gotta think!  Right to 2nd crack?  Oil on the beans too??  I can do 150g in the popper and its 10 or so minutes?  Can you stretch out the intervals and lower the temps?

Ive done quite alot of roasting over the past year with the $24 DSE heat gun. Id say my average roasting time with it would be about 15 mins. I agree 6mins lightning quick, it means there is not much time between just right and an overly dark roast.

As an experiment over the weekend Ill try the profiles suggested by luca and coffee_nuts, and let you know how they turn out.

Tim

[luca]

Re: IRoast Roasting Profiles??

Just a few quick notes, Tim,

a) The temp display might well be out of whack, so dont expect our roast profiles to necessarily be directly programmable into yours. Sorry, Andy, I know you wanted us to be able to transfer profiles around easily Of course, the correlation should be linear, so by snaking a thermocouple in through the chaff collector we should all be able to work out the offsets on our various I-Roasts. This would require no modifications

b) I just took a flick through Sweet Marias. Apparently a faulty chaff collector could be responsible for overly fast roast times. There are instructions on how to fix it here: http://www.sweetmarias.com/hearthware.iRoasttipsheet.html

(See "Quick Alteration to Chaff Collector for iRoasts that are running too dark")

Ive got to say that your unit sounds faulty to me ...

Cheers,

Luca

[luca]

Re: IRoast Roasting Profiles??

One idea that Ive been toying around with is a reference scale for roast colours, just to aid my own consistency, seeing as I cant hear any of the cracks. Heres my preliminary one.

Cheers,

Luca

[nunu]

Re: IRoast Roasting Profiles??

Most of my roasts fit in the -1 category. Between full city+ and french roast is where I prefer. Good for a start, I have to say. Maybe start where 5 is, and go darker.

[luca]

Re: IRoast Roasting Profiles??

Thought that I should put up a few of my roast profiles so far!

Over the last week, Ive liked a profile based on Tom of SMs generic city + ... or whatever its called. This profile is something like:

200C/7min
230C/3min
240C/2min ------> (You will probably stop the roast manually somewhere in this stage ... or set it for longer/add more if you want it darker)

An example:

Peru Kontiki, 14/10/05

204/7:00
230/3:00
245/1:15

140g/120g

This was a bit less than city roast, I guess, as depicted here: http://www.sweetmarias.com/roasted.pict-guide.html

I roasted this for vac pot cause we had Gabriel Gate coming over for dinner (he shops at the same supermarket and we keep on bumping into him).

Mountain Top, 22/10/05

202/7:00
230/3:00
240/0:20

142g/120g

This was roasted for Mark to use as a cupping roast. Well have a go of it today. My gut feeling is that it is a teensy bit darker than Mark likes for a cupping roast - should have stopped earlier to get more origin characteristics.

Timor Maubese, 16/10/05

200/6:30
230/4:00
240/2:00

142g/120g

My notes say slightly less next time, but I remember the last espresso from this batch, mixed with some Malabar, being exceptionally red and smooth.

Monsooned Malabar, 16/10/05

200/6:00
226/4:00
240/1:40

120g/102g

This ended up being sort of cinnamon coloured, as one would expect. Not quite musty, but ... different and vaguely spicy. Good choice, Andy.

Note that these figures are what I have programed into the machine. I have no idea what this actually correlates to. Exams are looming large, but after that Ill take a look around for a cheap multimeter. Also, take these figures with a grain of salt - remember that Im a total noob!

Cheers,

Luca

[TimA]

Re: IRoast Roasting Profiles??

These look great Luca. But can you tell me why you have two different weights at the end of each profile. Do you find your machine roasts hotter or cooler with a smaller amount of beans. Tim

[nunu]

Re: IRoast Roasting Profiles??

Looks like starting and finishing weights of the beans. 20g loss per batch is pretty typical.

[luca]

Re: IRoast Roasting Profiles??

Correct, nunu,

In terms of amount of beans, the volume is usually more or less identical, but I measure by weight. The Malabar is way out of whack because it is monsooned, but the volume was probably slightly more than usual. I have found the bean agitation to be better using 10g less than recommended. I dont have a multimeter, so I cant really say much about temperature, just what Ive set into my machine.

Ill probably move to Toms brazillian espresso profile, though, as its a softer start. (The mountain top that we played around with today was all over the place). Toms profile is something like:

176C/3:00
210C/4:00
230C/4:00

... but thats just from memory. You can see that it has a slower ramp-up. I guess that this would mirror the roast profile of a drum roaster a bit more, in that it is preheated and has a massive drop in temp when the beans are added, then slowly ramps up.

Ive got a quick snap of Marks rig to post up, too ...

Cheers,

Luca

[TimA]

Re: IRoast Roasting Profiles??



b) I just took a flick through Sweet Marias.  Apparently a faulty chaff collector could be responsible for overly fast roast times.  There are instructions on how to fix it here: http://www.sweetmarias.com/hearthware.iRoasttipsheet.html

(See "Quick Alteration to Chaff Collector for iRoasts that are running too dark")



Luca, I think you hit the nail on the head with this one. I made the mod outlined on sweetmarias. It took 5 mins and the machine is working a treat!. The onboard roasting temps were markedly lowered. The roasting times have been extended by at least several minutes and theres heaps of time to hit the cooldown cycle if needed.

Im now in the possition where I have a little too much roasted coffee from my experimenting. Oh well things could be alot worse!

Thanks for the help. Tim

[luca]

Re: IRoast Roasting Profiles??

Im now in the possition where I have a little too much roasted coffee from my experimenting. Oh well things could be alot worse!

Thanks for the help. Tim

Wow. Who new I could be helpful; Ive only been roasting for like two weeks!

Im with you on the roasted coffee thing. The family hit me up hard last week, so I was using like 1-2 day old beans and running out. Thank god that I picked up some Sulawesi Kolossi, roasted, from Mark D at St. Ali yesterday. I gave half the bag to an unexpected friend from Sydney, so Im imposing a moratorium on coffee tomorrow till my next stuff is ready.

Timor Maubese 24/10/05

180C/3:00
210C/4:00
235C/6:00

140g/116g

... but all of that is from memory.

Dont know how to describe the roast colour, either, other than really, really even. I guess that itd be a 1 or a 2 on the graphic that I posted earlier, but thats not saying much - its not a great scale! The first roast after you clean these things seems to be like that ...

... anyhoo,

Cheers,

Luca

[AndyCJ]

Re: IRoast Roasting Profiles??

Man... Ive got to get to St Ali, thats 3 times Ive heard the name mentioned in the last 30 minutes....

...maybe a trip at lunch on a rainy day (like today!)

[TimA]

Re: IRoast Roasting Profiles??

Has anyone roasted the Nicaraguan Altiplano in the I roast. The I roast seems to roast all my other beans beautifully evenly but the Nicarguan roasts fairly unevenly.

[imschris]

Re: IRoast Roasting Profiles??

Guys, I have been perplexed with my IRoast machine, since I bought it last November.
It would burn cofee to a crisp in a matter of 5 minutes. Aftrer reading about the chaff filter correction(and my machine was faulty in that respect), and performing the simple modification, things did improve somewhat.
Never the less, either my temperature readout is out of whack, or I dont know how others can roast for 10 or 12 minutes.
The best that I can do is 6 minutes, with settings of
Stage 1 162C for 2 minutes,
Stage 2 180C for 2 mins and
Stage 3 200C for 2 mins.
Using either Costa Rica or Guatemalla beans, and at an ambient temp of 27C. Quantity is about 1.6 scoops, with the scoop provided. The recommended maximum is 2 scoops, but I find that with this quantity, some of the beans dont reach the right colour.
The readouts are as followes: 1st minute 178C, second min 192C, 3rd min 201C, 4th min 209C, 5th min 213C, 6th min 218C.
(Shouldnt these temperatures be lower than set? Toms test at Sweet Marias suggest that they should be 20-30 degrees lower than those set!!!)
This gives me a darkish but not oily roast, which tastes as good as that purchased and roasted by the same coffee supplier.
This though makes nonsense of the pre programmed settings and what others are experiencing.
Perhaps the supplier of the equipment, if he monitors this, can provide an answer?
As it stands, I now go simply by colour. I use a sample of roasted beans of the same type from my supplier, and stop the roasting when it reaches that colour, and 6 minutes is it.

[Dimal]

Re: IRoast Roasting Profiles??

Hi imschris,

From what Ive been able to find out about the type of control these units use, it would seem that they are at best a simple Proportional Controller and more likely, an Open Loop Controller. What this basically means is that no matter what you do with regard to programming, you are always going to see an error between the temperature you set and the actual temperature inside the roasting chamber.... from what you have described of your own experience with your particular roaster, it is more likely that the latter of the two options of control is the method used.

I guess the only way you are going to "know" what the actual temperature is inside the roasting chamber, is to thread a thermocouple into the chamber somehow and attach this to an appropriate Digital Multimeter..... Jaycar and Dick Smith have suitable DMMs that come with their own t/couple and connector for less than $30.00. At least you would be able to plot a temperature profile for your I-Roast that correlates to the actuals you are trying to achieve. Im pretty sure that lots of owners in the USA have done this with their I-Roasts and there-after end up with a much more satisfying end result. Might be worth a go.....

Cheers,
Mal.

[imschris]

Re: IRoast Roasting Profiles??

Thank you Mal, Ill give it a try.

Chris