New to Roasting, ROR issues - Page 2

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
PeteNZ (original poster)
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Joined: 2 months ago

#11: Post by PeteNZ (original poster) »

Thanks for all the reply's. I will attach photos of my set up. Forgive me if these are daft questions in advance.

What i meant by negative ROR was from the time of dropping the beans the drum probe will start at 165c for example then keep slowly decreasing to where it stabilizes at 145c until the end of the roast, and that is true if I am taking it to FC or 2nd Crack. I am able to reach all stages of the roasting process.

Also, I am unsure if my probe is measuring air temp or bean temp come to think of it. I am not sure it goes far enough into the drum to measure BT, and from reading your replies it is most likely Air Temp which makes sense :)

Do the coffee beans have to be a certain temperature to reach each FC and 2nd Crack, or is it simply the coffee bean loosing moister or breaking down over time?

As far as recording goes I am just using a excel spread sheet and manually entering the data, and only recording Air temp.

I have conducted a boiling water test and the probes and it seemed to match up with the infrared temperate gun more or less.

Cheers

Marcelnl
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Joined: 10 years ago

#12: Post by Marcelnl »

Coffee beans reach first crack at around 200'C (differs per setup/measurement setup). I suspect we need to see the placement if the probes in your roaster to help you further, if they read 100'C in boiling water they likely are OK.

What are you using to read out the temp probes?
LMWDP #483

Milligan
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#13: Post by Milligan »

PeteNZ, I'd highly recommend reading some roasting literature to get a well rounded set of knowledge to build your roasts off of. Most start with Rao's roasting books. They are well worth the price of entry and have great information to get your started off on the right track. Basics such as what a graph should look like, charge temp ranges, rough guide to roast times, what to look for in RoR, rough FC temperatures and finish times/ratios/temps are discussed. That will give you the foundational knowledge to build off of.

I'd also highly suggest learning to use the Artisan roasting program to automatically log your roasts and to be easily able to better diagnose issues and share your data with others for suggestions. I wouldn't want you to waste your valuable time inputing data into a spreadsheet when such a robust program exists (and for free/donations.)

Nunas
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#14: Post by Nunas »

PeteNZ wrote:<snip>What i meant by negative ROR was from the time of dropping the beans the drum probe will start at 165c for example then keep slowly decreasing to where it stabilizes at 145c until the end of the roast, and that is true if I am taking it to FC or 2nd Crack. I am able to reach all stages of the roasting process. Also, I am unsure if my probe is measuring air temp or bean temp come to think of it. I am not sure it goes far enough into the drum to measure BT, and from reading your replies it is most likely Air Temp which makes sense :) Do the coffee beans have to be a certain temperature to reach each FC and 2nd Crack, or is it simply the coffee bean loosing moister or breaking down over time? <snip>
Here are a few thoughts about your issue.
The BT probe must contact the beans.
When the drum is empty, the BT probe measures the air temperature.
If you also have an ET probe (higher up in the drum where it won't contact the beans), the BT and ET should be about the same temperature with an empty drum (assuming a reasonable air flow through the drum).
When you charge (beans enter the drum), the BT will drop rapidly, due to the cold beans engaging with the BT probe. ET will drop more slowly.
After a few minutes, the BT should begin to rise, as the BT probe and the beans finally agree on what the temperature is :lol: From this point on, the BT is useful.
When BT hits about 150 C, you should see the beans turn from olive drab to tan. This is artificially termed end of drying, which it actually isn't...the beans continue to dry internally.
As mentioned by another responder, with most greens, 1C start should happen at 200 C +/ a few degrees.
1C end usually happens about 15-17 degrees C higher than 1C start.
2C start happens at about 225 C. 2C start varies much more than 1C start.
Charging the roaster at 165 C is rather low; I charge at 210 to 225, depending on the ambient temperature.
If you get to 1C start and your BT does not read ~200 C, there's something wrong. It could be probe placement, or a type mismatch between the probe and the setting of your thermometer. https://www.precisionmass.com/types-and ... rmocouple/

Pressino
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#15: Post by Pressino »

Did you check to make sure you haven't inserted your thermocouple into the meter with reversed polarity, as was suggested earlier by rmongiovi as a reason you might be recording negative RoR temps during your roast. Note that this could also explain the lower than expected readings. Clearly your TC is reading lower than actual temperatures, since you say the beans are going through first crack. Try reversing the TC polarity and see what you get.

PeteNZ (original poster)
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Joined: 2 months ago

#16: Post by PeteNZ (original poster) »

Hey, do you mean how am I readying the temps of the probes I have? They are just being displayed on the control panel. The roaster is does not have the ability to connect to USB just yet.

PeteNZ (original poster)
Posts: 8
Joined: 2 months ago

#17: Post by PeteNZ (original poster) »

Hey thanks for the reply, If I am able to hit all the stages of the roast there must be something up with the placement of the probe, I have tried to move the probe as far as I can into the drum without it touching the veins. My probes seem quite chunky and its been suggested that I use a skinner probe for better results.

PeteNZ (original poster)
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Joined: 2 months ago

#18: Post by PeteNZ (original poster) »

Ok, will give it a crack with the reverse polarity...if I know how to do that lol. Cheers a lot to learn!

Marcelnl
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#19: Post by Marcelnl »

PeteNZ wrote:Hey thanks for the reply, If I am able to hit all the stages of the roast there must be something up with the placement of the probe, I have tried to move the probe as far as I can into the drum without it touching the veins. My probes seem quite chunky and its been suggested that I use a skinner probe for better results.
just wait with that until you get things to work, a smaller diameter probe is faster but does the same thing ;-)
Drum load percentage is likely more important for BT accuracy for now, luckily you do not have to waste 1.7kg or so of beans to test polarity of the TC just fire up that machine for a bit.
LMWDP #483

PeteNZ (original poster)
Posts: 8
Joined: 2 months ago

#20: Post by PeteNZ (original poster) »

My Drum goes in a clockwise direction with the BT probe in the 10 o clock position on the upper left, I have read that the BT probe should be on the lower left hand side if I wanted to get the probe more into the bean mass? I am no electrician and I'm not sure if I want to be messing with the polarity of my machine, with my luck ill burn the garage down. Any tips for this?