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New to roasting. Could you help me with roasting advice?
Ben N
I think many of your lessons learned will translate to any roaster in the future. Maybe not directly but the knowledge of bean behavior during the roast, and your own preferences will work with another machine. And it seems there is always more to learn, the logging really helps.

I also like my artisan based SR, it does what I want in a batch size that lets me roast often :)
 
Skyhawk4

Quote

Ben N wrote:

I think many of your lessons learned will translate to any roaster in the future. Maybe not directly but the knowledge of bean behavior during the roast, and your own preferences will work with another machine. And it seems there is always more to learn, the logging really helps.

I also like my artisan based SR, it does what I want in a batch size that lets me roast often :)


I'm curious, with your SR do you have a sweet-spot overall time range for your roasts that you try to keep within? My best medium roasts seem to be in that 8 to 9 minute range. I have had some good tasting coffee from longer roasts too though.
 
oldwood

Quote

Skyhawk4 wrote:

Quote

Ben N wrote:

I think many of your lessons learned will translate to any roaster in the future. Maybe not directly but the knowledge of bean behavior during the roast, and your own preferences will work with another machine. And it seems there is always more to learn, the logging really helps.

I also like my artisan based SR, it does what I want in a batch size that lets me roast often :)


I'm curious, with your SR do you have a sweet-spot overall time range for your roasts that you try to keep within? My best medium roasts seem to be in that 8 to 9 minute range. I have had some good tasting coffee from longer roasts too though.


I recently read this; "The overwhelming industry consensus, from 3rd Wave roasters to Folger's, is that roast times under 7 minutes or over 14 are not good. Another overwhelming consensus is that environmental temperatures above 500F are not good. A less strong consensus, but one held by all the third wavers, sees roast profiles that are described as Slow Start/Fast Finish as better than Fast Start/Slow Finish profiles."

This is from this thread,
https://www.home-barista.com/roasting/timing-first-crack-heat-reduction-t11144.html

I had previously read this, "Basically, this magic profile is a starting temperature of around 325F to 400F, and a ramp up to around 450F to 480F in around 6 to 8 minutes, and holding it steady there to the end of the roast, whenever that may occur."

For some reason, I interpreted the whenever that may occur part to imply it was not important when it occurred, but have changed my roasting technique, so my roasts end at around 13 minutes and have seen an improvement in the taste.

I am using a DIY mesh drum roaster, but it seems Jim's advice applies to all types.
 
renatoa
Jim states clearly that his formula is for hot air machines.
And also, do not skip the second half part of the quote, is equally important as the numbers:

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This ET part is basic roasting chemistry, and the same for all roasters and coffees.
But the heat inputs required moment by moment to achieve this ET curve is based on the roaster's thermal characteristics, and is different for every roaster design. "


No, for machines not based on hot air ET is less or not relevant at all.
For example the IR roasting machines, as recently Skywalker roaster shows. ET in that machine is the lowest temperature in the whole chain. Go figure...
Even the continuous declining RoR mantra is no more mandatory to have awesome roasts.

Old style big machines commercial roasters often goes into 15-20 minutes and they get good results... because so demand the machine, and heat transfer specifics.

Machine heat transfer understanding is the most important, more than adopting someone "consensus", without understanding how your/others machine work.
 
oldwood
"Machine heat transfer understanding is the most important, more than adopting someone "consensus", without understanding how your/others machine work."

Once again, my attempts to find a simple solution to a complex problem are dashed ;)

My problem with my roaster is I can not track the bean temp as I can not insert a probe in the bean mass. I must work ET and time.

Thanks, Gerry
 
renatoa
Solution is simple, if you know that in hot air machines ET is a function of power. Not totally proportional but close.
Other words, if you read 150C ET at 40% power, then there are great chances to have 220-225C at 60%.
More about this approach here: https://homeroast...post_74953
 
oldwood

Quote

renatoa wrote:

Solution is simple, if you know that in hot air machines ET is a function of power. Not totally proportional but close.
Other words, if you read 150C ET at 40% power, then there are great chances to have 220-225C at 60%.
More about this approach here: https://homeroast...post_74953


That makes good sense for the air roaster. For my situation I have a resistance style electric element at the back of the roaster that has only an on off control and a heat gun that gives me air flow and extra heat, so I can get fine control of the ET. I use a kilowatt style meter to give a better idea of what the gun is putting out. I think the 2 heat sources is going to make the formula complicated and messy ;)

If the temp is controlled and the air flow is increased, would the heat transfer rate to the beans also increase, or is the temp the only controlling factor? I try to control air flow direction so it is forced over the beans in the drum, but have no volume control of air.
 
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