roast profiles... HOW??

Roasters and roasting

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roast profiles... HOW??

Postby NottmSteve » Mon Aug 24, 2009 9:46 pm

I read all about roast profiles everywhere.

Including the sticky at the top of this forum sub group.

I see the software and the lovely charts. I have a nice netbook to download the software. Those curves look sexy...

BUT HOW do you connect up to the roaster to get the damn charts?

I have a hottop B.

Do I need a pobe installing and some electrical gubbins? So many people are showing / comparing / creating the charts that I guess it must be easy?

HELP, please. I'm in England, and have the Hottop B if this makes a difference on what to buy and where etc.

Cheers
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RE: roast profiles... HOW??

Postby Jasonscheltus » Tue Aug 25, 2009 4:51 am

you can do it with a fancy thermometer and a thermocouple. I think the Fluke handheld thermometers have this capability. There are some hand-held thermometers that send a signal back to a laptop through a dongle thing. Have a look through Omega electronics - they've got loads of stuff but you can probably get better prices from somewhere else.

I'm not sure about the Hottop - Steve the Van could prolly help.
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RE: roast profiles... HOW??

Postby dsc » Tue Aug 25, 2009 11:49 am

Hi Steve,

you can get the Fluke datalogger which is insanely expensive, or get the Omega HH806 (of the top of my head so not 100% sure about the number) for a bit less, around 160£ or so. It's a two channel device which means you can grab data from two probes and plot it. The software is cheap and it does pretty much all you want. I haven't got one, but I want one from Santa:)

Regards,
dsc.
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RE: roast profiles... HOW??

Postby bruceb » Tue Aug 25, 2009 12:26 pm

I, too, am coveting a datalogger, but it will have to wait for the moment.

Something to be considered is the value of the data you might be logging. Most home roasters, the HotTop included do not have any capability to measure the bean mass temperature. They generally measure the temperature of the hot air entering or exiting the drum. This provides a "reproducible artifact, so to speak. You can use it as a guide once you have enough empirical data from past experience, but it is only a guide at best because other parameters (size of the bean mass, moisture content of the green beans, etc. will vary and change the final roast product accordingly, regardless of measured temperature. In other words, the only "objective" data that might be useful for assurance of reproducibility is the actual temperature of the beans during roasting, and this data is not available for the simple reason that it is mechanically too difficult to measure bean temperature in a rotating drum.

That said, I still would like to have a data logger, although I make do with noting the temperature (in my commercial 1-pound sample roaster) every minute and manually drawing a curve at the end. The downside of this is that it keeps me so busy that I can't really manually change the profile while roasting.
Three Francesconi (CMA) espresso machines - Rossi, San Marco, LaCimbali, Faema and 2 Mazzer Major grinders- CoffeeTech Maggionlino, Hottop, Alpenröst and HW Precision roasters.
I decided I needed a bit of a change so I roasted some Monsooned Malabar. That was a change!
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Re: roast profiles... HOW??

Postby GreenBean » Wed Aug 26, 2009 8:03 am

NottmSteve wrote:Do I need a pobe installing and some electrical gubbins? So many people are showing / comparing / creating the charts that I guess it must be easy?


You do not have to install electrical gubbins as long as you are willing to take readings of the temperature each minute as Bruce suggests.

Some people do add such gubbins and you will see much discussion of bean mass temperature and environment temperature. I do not disagree with anything Bruce says above but I find that, in practice when using a consistent bean mass, the Hottop temperature readings are representative enough to allow you to predict when first crack will start/end and, therefore, when heater power should be adjusted.

I think that it is invaluable to take readings when learning to roast. Being constantly by the roaster watching listening and smelling what is happening. I would recommend comparing your roast profile with a previous good roast as it progresses. You can do this by just plotting the temperature on a graph which has a known good previous roast plotted on it or by using suitable software, spreadsheet, roast logger or the Coffee Roast Database.

If you wish to add additional temperature probes there are many digital multimeters that will measure temperature. Some have serial or usb interfaces to allow readings to be transferred to a computer. The software required to log the data is generally suitable for a specific multimeter only and usually only Windows OS.

I have been playing with a way to automatically log temperature readings from my Hottop (or just about any other LCD or LED digital display) without any electrical connection to the roaster (or digital display) and at no cost. This started as a joke and a bit of a bet with my Son but I am astonished that it is working well for me and I use it to log and chart all my roasts but I do not know if it would be suitable for others to use. The following is a screen shot of it running showing a current roast profile against a selected template profile.


Image
Image

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RE: Re: roast profiles... HOW??

Postby bruceb » Wed Aug 26, 2009 10:22 am

Yes, perhaps I was not careful enough in my wording. The temperature indication from the HotTop is fully adequate if green bean mass is always the same. My aim in writing the above was to remind people not to let the tail wag the dog. Putting big money and efforts into a data logging system that is logging questionable data is not sensible. At the same time I really would like to not have to sit with my eyes nailed to a timer and the temperature readout throughout the 15-18 minute roast cycle. Instead, my eyes are now nailed on ebay with the hope of finding a Fluke or other logger. I would prefer an interface that couples directly via usb or serial cable to a pc. There are a number of these available, but most of them have at least 16 input ports and all I need is 1 or at the most 2. I'll keep watching.
Three Francesconi (CMA) espresso machines - Rossi, San Marco, LaCimbali, Faema and 2 Mazzer Major grinders- CoffeeTech Maggionlino, Hottop, Alpenröst and HW Precision roasters.
I decided I needed a bit of a change so I roasted some Monsooned Malabar. That was a change!
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RE: Re: roast profiles... HOW??

Postby NottmSteve » Wed Aug 26, 2009 9:56 pm

Cool....

So I just write the temp down on the HT led display, every minute, and draw (or use a pc) my graph? Is that right?

Guess I forgot the led display completely, lost in thoughts of expensive extra kit.

I'm still struggling to ascertain when 1st ends and 2nd begins, so I think charting will help me visualise roasting.

As things stand, I use auto and just dump when I am fairly sure 2nd crack has commenced.

I need to get better!

I find a lot of profiling threads go over my head and there is little out there to help a novice in the area. I don't even know what a good profile is (one that I just like the end cup taste?).

Thanks for the comments.
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RE: Re: roast profiles... HOW??

Postby NottmSteve » Wed Aug 26, 2009 9:58 pm

PS, greenbean, if you have any top tips for a novice to kick start me, drop me a pm and I'll give you my email.
Steve
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RE: Re: roast profiles... HOW??

Postby bruceb » Thu Aug 27, 2009 5:12 am

After well over 1000 roasts on the digital (not programmable) HotTop I can say that it is possible to get great roasts without looking at anything, possibly aside from the smoke coming out the top. I always pressed "time" to the maximum and then used the plus button to add minutes as necessary. After 1st crack begins I sometimes watched the temperature readout, which unfortunately only lasts a few seconds after you press the button, but it does give a good indication of where you are. On the other hand, listening for the beginning and of first and then the first cracks of second and on to rolling second (if desired) plus the smell and amount of smoke gives enough indication.

The HT is very sensitive to bean mass (I use a laboratory scales) and also to the time after the beeps begin that you dump in the beans and close the chute. It's good to be very constant about these things so you don't enter more variables into the process. I found it much easier to get a good, reliable roast with the HT than with any other roaster I've used, including the various hot air roasters, the plastic Gene and the Alpenröst (my second favourite roaster) plus my new commercial 1-pound sample roaster and Probat sample roaster.
Three Francesconi (CMA) espresso machines - Rossi, San Marco, LaCimbali, Faema and 2 Mazzer Major grinders- CoffeeTech Maggionlino, Hottop, Alpenröst and HW Precision roasters.
I decided I needed a bit of a change so I roasted some Monsooned Malabar. That was a change!
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Re: RE: Re: roast profiles... HOW??

Postby GreenBean » Thu Aug 27, 2009 7:41 am

NottmSteve wrote:So I just write the temp down on the HT led display, every minute, and draw (or use a pc) my graph? Is that right?

Yes that is it and, assuming you stick to one bean mass, is all you need for the first several hundred roasts! After that you may be in a position to say that you could improve even further if you had environment and bean mass temperature readings. The screen shot in my previous post is a chart of readings taken from the Hottop digital display.

I have never used the Hottop B model so you would be better getting specific advice from others who roast on the B. You should pick a bean that is easy to roast, I would strongly recommend the Machacamarca from Hasbean.

For me logging the roasts has two main benefits one is simply to produce a record so that when you taste the coffee several days later you can look back to try to determine why this roast is better or worse or just different to previous roasts. The second is even more important to me. This is to help you learn to predict what is going to happen and when so that you can stop being an observer in the roast process and start to control it. The Hottop heating element takes some time (in the order of a minute) to respond more or less fully to a change in power input. This means you need to reduce the power input ahead of the time you want the heater output to drop. In my Hottop P (modified with heater power control) I aim to reduce heater power to about 75% 60 seconds before first crack starts and to reduce it much further about half way through first crack. This is not possible until you can reliably predict how the roast is going. If you get it wrong and lower the heater power too much, too soon the roast will stall. I can only achieve this by comparing how the current roast is progressing compared to a previous good roast of the same mass of the same beans.

Automatic logging and charting of the roast against a template roast makes the above much easier giving you the information you need in time to control what is happening.

I will post some more details of the roast logger I am using in the Members area in case anyone is interested in trying it to see if it is suitable for others to use.
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