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rival81

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I posted this on my blog (www.brewmethod.com) a while ago, but thought i would share it here.

Introduction to espresso coffee roasting

Espresso roasting - how long should you roast and to what finish temperature? The correct answer is whatever tastes best to you. I won't try to tell you what roast depth you should like, or that you should like the same thing i like. But if you're looking for a basic guide, here's what and how i roast for espresso.

Roast time and temperature

Roast time duration, and the end temperature are still two variables you will rarely find on a bag of coffee. The reasons are obvious - different roasters use different thermoprobes all designed in unique ways and while they all may serve the same function (to give a consistent temperature readout roast to roast on the same machine), you can't compare temperatures easily between different roasters.

However i still feel it is useful for home roasters to discuss these variables, if not for sharing exact numbers then at least for sharing roast styles and techniques for particular coffee origins.  As a home roaster starting out, i had no clue what temperatures i should be aiming for at what time during each roast phase. Only through roasting, tasting, roasting and then tasting again week after week have i been able to really get an understanding of how to roast well.

I'm not a pro roaster


I won't try to claim that my roasts are better than anybody elses, but i will say that for my own personal taste (which is generally an espresso roast on the lighter side to retain a higher amount of acidity) i am very happy with the results most of the time.

Here is a basic guide that should, in theory, yield some pretty tasty roasted coffee if you have built a home coffee roaster, have it insulated, have a way of easily controlling/changing the input temperature throughout the roast and a method of cooling the beans quickly. Every coffee has different requirements, but in general this is the roast profile that i use as a first test roast with a new coffee, and then adjust accordingly from there based on taste after at least 4 days of degassing.

Pre heat

First step is i pre heat the roaster to around 210 degrees celcius.

Dump

Then once temperatures have stabilised, i enable the magic agitation device and dump in the extraordinarily high quality green coffee beans sourced from the likes of Ministry Grounds. Always try to use the same roast mass for consistency - for me that is 480g.

Drying phase

At this stage, i've got heat on a medium setting. My temp control is a dial with numbers, so i have completely variable control at all times during the roast. Temperature in the bean mass generally reaches 70 degrees after 1 minute, 100 degrees after 3.5 minutes. This is the initial drying phase. Once i reach 100 degrees i generally back off the heat input just a little bit.

It's important to keep a very close eye on the rate of temperature increase. I generally do not need to make any further adjustments until 1 minute before first crack. That is at the 9 minute mark around 185 degrees, i reduce heat further to slow the temperature increase to 4 - 5 degrees per minute.

First crack

First crack is around 195 degrees at 10:15, and temps increase 4 - 5 degrees per minute from here until i pull the roast at 212 to 214 degrees at around 14:00 - 14:30.

Finishing the roast

Deciding when to pull the roast is critical. You should be sampling from 208 degrees on until you are seeing the roast colour and have reached the roast temperature which you like the taste of in the cup. For me, anything beyond 214 and i start to notice a marked decrease in acidity and sweetness (in some coffees, not all). Anything less than 208 is too acidic and although it still tastes great and super sweet i find it's too much acid for my stomach.

You must cool quickly or the beans will continue to roast on the inside and you risk having over-roasted coffee on the inside of the beans and lighter roasted coffee on the outside.

Bag in a one-way valve bag and seal with a heat sealer (hint: cheap ones on ebay, it's probably okay to skimp on a heat sealer). Degas for at least 3 - 5 days before tasting.

For some more specific temps, refer to my previous roast logs. Note that a lot of my old roast logs were 15 minute roasts. I now generally use 14:15 roasts as i *think* these taste a little better... maybe.  I never roast into or beyond second crack, but many do and they can still taste great.

Temp at first crack - a good point of reference

Please be aware that depending on your roasting setup, your temp readings could be completely different to mine, maybe even 5 or 10 degrees higher or lower at first crack. But you can generally use first crack as a guideline for comparing your temp readings with other roasters. For example if i reach first crack at 195 degrees, and my buddy reaches first crack at 200 degrees, then in theory his end temp 5 degrees higher than mine at the same time should, maybe, be a similar roast depth.



GaryatGala

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« Reply #1 on: 29/09/2011, 04:49 PM »
Thanks for the guide.

Although it;s a good guide, people should only use it as a guide as such and not to follow it to the letter due to different factors like the equipment being used, the beans and the external environment.

I have two domestic roasters. One a FZ-RR700 Baby Roaster and the other a covered coretto.

For the Baby, the best results have been full heat initially til a minute before first crack then taper off the heat to a moderate to low setting to ease into first crack so the roast doesn't run away from you. Maintaining the moderate to low heat setting for a steady rise of 4-5 degrees a minute then pull the roast at the start of second crack.
I drink espresso so i generally prefer start of second c to balance origin characters with sweetness/acidity/bitterness.

For the coretto so far i've only gone so far as to apply the same roasting profile as the Bay Roaster, but has anyone followed a profile of moderate heat, then ramp up at 150 deg then taper off at first crack?
I came across this at a different forum and i thought it makes sense, since initially we're drying the beans at the start, then apply maximum heat for the maillards reactions from 150 til 185 degrees celcius, then lower heat for first crack.

I guess some would be wondering about this too.
I could do a comparison between two batches. One from the original profile and then one from the ramp up profile from both the Baby Roaster and the coretto. Tasting the results a few days later and then post results.

Would anyone like to share their findings?

Gary at G
KKTO; FZ-RR700 Baby Roaster; triple  corettos; Simonelli Oscar; Compak K3T; Rancilio Silvia and Auber PID; 2 V60s; CCD; Aeropress; home made bean cooler and a blue worker sad sack of less than 10 kg of greens.
Work: Suzuki APV van. Honda EU65i. Compak K8. Expobar Elegance Compact. Roband pie warmer.

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« Reply #2 on: 30/09/2011, 02:03 PM »
Thanks for the guide.

Although it;s a good guide, people should only use it as a guide as such and not to follow it to the letter due to different factors like the equipment being used, the beans and the external environment.

I have two domestic roasters. One a FZ-RR700 Baby Roaster and the other a covered coretto.

For the Baby, the best results have been full heat initially til a minute before first crack then taper off the heat to a moderate to low setting to ease into first crack so the roast doesn't run away from you. Maintaining the moderate to low heat setting for a steady rise of 4-5 degrees a minute then pull the roast at the start of second crack.
I drink espresso so i generally prefer start of second c to balance origin characters with sweetness/acidity/bitterness.

For the coretto so far i've only gone so far as to apply the same roasting profile as the Bay Roaster, but has anyone followed a profile of moderate heat, then ramp up at 150 deg then taper off at first crack?
I came across this at a different forum and i thought it makes sense, since initially we're drying the beans at the start, then apply maximum heat for the maillards reactions from 150 til 185 degrees celcius, then lower heat for first crack.

I guess some would be wondering about this too.
I could do a comparison between two batches. One from the original profile and then one from the ramp up profile from both the Baby Roaster and the coretto. Tasting the results a few days later and then post results.

Would anyone like to share their findings?

Gary at G

I still struggle to get sufficient heat with my corretto (if length of roast time is any indication) so I do a five min pre-heat then ramp all the way, then pull at first signs of second crack - but I must say it still produces lovely coffee!
"The crema which dissipates is not the lasting crema..."

GaryatGala

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« Reply #3 on: 30/09/2011, 06:50 PM »
How long are your roasts askthecoffeeguy?

Being a fluid bed design i'm presuming it shouldnt take too long compared to say a KKTO, otherwise flavours become bland??

Normally i aim for 10min approx til first, then 3-4 minutes til second.

I'm in a pain in a butt situation because i'm the only one drinking coffee in my household, so i only roast once every 2 weeks.
I'll bet someone will put their hand up and say "Oh oh!! i'll speed it up. Send me your coffee and i'll gladly drink it  ;D"

Right then. This Sunday i'll do two batches on the Baby Roaster.
One batch following the conventional full heat then taper off before first crack.

Second batch for a gentle drying out til 150 degrees celcius then ramp it up til first crack at 195 degrees then taper off and coast to second.

Will report the findings in the cup a few days later after Sunday.

Cya next week.

Gary at G
KKTO; FZ-RR700 Baby Roaster; triple  corettos; Simonelli Oscar; Compak K3T; Rancilio Silvia and Auber PID; 2 V60s; CCD; Aeropress; home made bean cooler and a blue worker sad sack of less than 10 kg of greens.
Work: Suzuki APV van. Honda EU65i. Compak K8. Expobar Elegance Compact. Roband pie warmer.

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« Reply #4 on: 30/09/2011, 10:26 PM »


Drying phase

At this stage, i've got heat on a medium setting. My temp control is a dial with numbers, so i have completely variable control at all times during the roast. Temperature in the bean mass generally reaches 70 degrees after 1 minute, 100 degrees after 3.5 minutes. This is the initial drying phase. Once i reach 100 degrees i generally back off the heat input just a little bit.

It's important to keep a very close eye on the rate of temperature increase. I generally do not need to make any further adjustments until 1 minute before first crack. That is at the 9 minute mark around 185 degrees, i reduce heat further to slow the temperature increase to 4 - 5 degrees per minute.



When monitoring your roast in the early stages you need to look at your turning point - the moment when the rate of temp drop has "bottomed out" and the beans start to heat up and your initial ramp is underway.

Turning point (TP) ranges vary depending upon the roasting device, charge temp, bean mass & type, energy source (heat) and the environmental conditions such as ambient temp of beans, etc.

For roast devices that use some forms of conduction and convection, e.g. a drum, etc. you should be trying to look for a turning point between 2:30 and at perhaps 3:00 mins.

I find TP calcs a highly valuable indicator on whether I've worked out the correct ratios of green kg's, charge temp, energy applied, drum speed and airflow. So important is this for me that when roasting a new bean I will do some very quick sums in my head based on experience and try to run ahead of the profile curve to predict (or visualize) how the bean will behave in the chamber during the execution of the roast. It's a particularly fun game for those times when you are shackled to the roaster for 11hrs straight  ???.

Just like a surfer getting into the precise position for takeoff on a classic wave, or a golfer seeking to position the ball in a certain zone for the next shot, the TP can be a very useful gauge to "SETUP" the roast so that you have the right variables in play for the important temp ramps - making it that much easier to control and manage the roast, rather than respond or react to the roast.

Hot air roasters behave a little differently in respect to TP's but this is still an influential checkpoint on the journey to that perfect batch !

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« Reply #5 on: 01/10/2011, 01:58 AM »
How long are your roasts askthecoffeeguy?

Being a fluid bed design i'm presuming it shouldnt take too long compared to say a KKTO, otherwise flavours become bland??

Normally i aim for 10min approx til first, then 3-4 minutes til second.

I'm in a pain in a butt situation because i'm the only one drinking coffee in my household, so i only roast once every 2 weeks.
I'll bet someone will put their hand up and say "Oh oh!! i'll speed it up. Send me your coffee and i'll gladly drink it  ;D"

Right then. This Sunday i'll do two batches on the Baby Roaster.
One batch following the conventional full heat then taper off before first crack.

Second batch for a gentle drying out til 150 degrees celcius then ramp it up til first crack at 195 degrees then taper off and coast to second.

Will report the findings in the cup a few days later after Sunday.

Cya next week.

Gary at G

I have a KKTO and a quick roast is 22mins to first crack and 26mins to second  - but most tend to go to the 30min mark - sometimes a bit longer

If I insulate the KKTO by wrapping it up in a blanket I can shave a few minutes off - but still it's a lot longer than I thought it would be...
"The crema which dissipates is not the lasting crema..."

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« Reply #6 on: 01/10/2011, 09:07 AM »
I have a KKTO and a quick roast is 22mins to first crack and 26mins to second  - but most tend to go to the 30min mark - sometimes a bit longer

If I insulate the KKTO by wrapping it up in a blanket I can shave a few minutes off - but still it's a lot longer than I thought it would be...


ACG try a new Turbo Oven
As those roast times seem a little long
You know I am available to chat at any time

KK
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Blog - http://koffeekosmo.blogspot.com

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« Reply #7 on: 01/10/2011, 10:56 AM »
Jeff, interesting and informative post as ever. I am pretty sure my TP is quicker than that in the hottop, but will check. As of last night, I now have the hottop temp sensor, BT, ET, ROR, heat power and elapsed time displayed, so should be a lot easier than before.

Anything else I should be monitoring?
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« Reply #8 on: 01/10/2011, 11:27 AM »
Jeff, interesting and informative post as ever. I am pretty sure my TP is quicker than that in the hottop, but will check. As of last night, I now have the hottop temp sensor, BT, ET, ROR, heat power and elapsed time displayed, so should be a lot easier than before.

Anything else I should be monitoring?

That's most likely true UNM - roasting devices using predominantly hot air, or smaller batch roasters have very quick TP's. In very small roast batches, the TP is less critical as the transformation events occur so fast. In fact, the larger batch size you do, the more important the TP is likely to be in the scheme of the overall roast profile. Some very large roasters use a highly detailed approach and preset intervals associated with the heat, charge, dry, TP and initial ramp - possibly involving numerous steps and set points before the roast is on it's way.

There are some very important stages leading up to and just after first crack that are deal-makers or deal-breakers. Adjustments to your roast during these phases are akin to walking a high-trapeze tightrope - recommended only for the advanced roasters to attempt. Sounds like a tease, but I will post a note on that rough diamond in a few weeks time........ ::)

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« Reply #9 on: 01/10/2011, 09:28 PM »
Now that I have the basic profile down pat that appears to work on all the beans so far, I want to start the tweaking in getting to first crack, lots of reading but I haven't found anything so far that really gives me a rough guide on where to start.
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« Reply #10 on: 01/10/2011, 11:15 PM »
Now that I have the basic profile down pat that appears to work on all the beans so far, I want to start the tweaking in getting to first crack, lots of reading but I haven't found anything so far that really gives me a rough guide on where to start.

Bear in mind I am a noob to roasting too.

simple popper profile:
Short, fast, loud

Add manual control - first step is to lengthen the roast time, both been there, done that.

Next  step for me was to have fast initial heat, lengthen mid duration, quick ramp to 1c and long period to 2C.

I was just beginning to research profiles when the popper died and I had to start on a drum roaster that plays a bit differently. Accurate BT measurement on the hottop are both a boon and a curse as I am relearning. When zombieroaster rises, I will continue playing with fluid bed just for fun.

Good thing about fluid bed and small batch seems to be ability to change heat quickly. Play with that - try some funky profiles. Slow/fast dry, slow/fast maillard reaction, slow/fast to 1c, slow/fast to 2c.  I think that is 16 suggestions in one post, so probably not that helpful really :-\



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« Reply #11 on: 02/10/2011, 11:25 AM »
ACG try a new Turbo Oven
As those roast times seem a little long
You know I am available to chat at any time

KK

is it just a matter of buying a new oven and popping the lid on top?
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« Reply #12 on: 02/10/2011, 11:54 AM »
is it just a matter of buying a new oven and popping the lid on top?

Pretty much just swap one Turbo Oven for the other
Recently I also purchased a halogen type with light Turbo Oven to test and to be used as a back up / spare TO just in case
You can also give the current oven to the wife with the new bowl and she can do regular cooking with it
That's a win win

KK


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« Reply #13 on: 02/10/2011, 01:25 PM »
Pretty much just swap one Turbo Oven for the other
Recently I also purchased a halogen type with light Turbo Oven to test and to be used as a back up / spare TO just in case
You can also give the current oven to the wife with the new bowl and she can do regular cooking with it
That's a win win

KK

I'm guessing that the lid sizes would need to be the same to fit the adapter ring that fits into the pot?  33cm diamater - is that right?
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« Reply #14 on: 02/10/2011, 02:11 PM »
I'm guessing that the lid sizes would need to be the same to fit the adapter ring that fits into the pot?  33cm diamater - is that right?

The TO is 32cm the adapter is 33cm
However I see you problem with long times
I made a revision last year on the operation of the KKTO
1) The adapter should only be used for small green bean batches of 400 gr or less
2) Update the roaster by fitting high temp silicone tubing and a double agitator (and you have those)

Once the tubing is fitted the adapter should not be used  
See photo for correct fitting
The TO sits on top of the tubing but also overlaps the pots (and this is normal)
External insulation will help to retain available heat and also increase green bean batch sises

So before you get a new TO try the above
And PM or ring me for any query you may have
I will email you the KKTO assembly PDF so you can have a read  :D

KK
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« Reply #15 on: 02/10/2011, 03:00 PM »
pm sent
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« Reply #16 on: 13/12/2011, 04:51 PM »
For the Baby, the best results have been full heat initially til a minute before first crack then taper off the heat to a moderate to low setting to ease into first crack so the roast doesn't run away from you. Maintaining the moderate to low heat setting for a steady rise of 4-5 degrees a minute then pull the roast at the start of second crack.
I drink espresso so i generally prefer start of second c to balance origin characters with sweetness/acidity/bitterness.

Hey Gary, how do you measure the temperature with this roaster? I ask because that's what I have and I've been sort of seat of the pants flying it so far. Which is doing OK but I wonder how I can get it better.

Edit: Might be OK, had not caught up with latest posts on thread elsewhere.

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« Reply #17 on: 13/12/2011, 05:02 PM »
Hey Gary, how do you measure the temperature with this roaster? I ask because that's what I have and I've been sort of seat of the pants flying it so far. Which is doing OK but I wonder how I can get it better.

Edit: Might be OK, had not caught up with latest posts on thread elsewhere.

I might be able to answer that for you Sidoney & may help the next person with the same question

I will let a diagram show you

KK
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« Reply #18 on: 13/12/2011, 05:07 PM »
Thanks KK, that's useful.

My main concern with my roaster is that the whole thing (apart from the stand) rotates, although thinking about it the little cap thing on the side rotates less - I have the motorised version of the Baby Roaster.

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« Reply #19 on: 13/12/2011, 05:12 PM »
Thanks KK, that's useful.

My main concern with my roaster is that the whole thing (apart from the stand) rotates, although thinking about it the little cap thing on the side rotates less - I have the motorised version of the Baby Roaster.

It can be done with a little know-how

KK
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« Reply #20 on: 16/12/2011, 12:59 AM »
Turning point (TP) ranges vary depending upon the roasting device, charge temp, bean mass & type, energy source (heat) and the environmental conditions such as ambient temp of beans, etc.

To that list of things influencing TP, I would add "temperature probe." 

I strongly suspect that the thermal lag created by the sleeved thermocouple probe in my Hottop is the primary factor in both the time to TP, and the bottom temperature at TP.  In my situation, I think the fact there is a TP at all is more an artifact of temperature sensing than it is an indication of roast conditions.

While I don't necessarily claim that's true for all roasters and probes, I do think the probe style and placement plays a bigger role than you might assume.

Jim

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« Reply #21 on: 27/06/2016, 04:07 PM »
I think One of the best ways you could ever hope to enjoy coffee is by roasting it yourself. When you roast coffee at home, you guarantee that every cup of coffee you make will be fresh and, with a little practice, you can ensure that it is roasted exactly to your taste.

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« Reply #22 on: 16/08/2016, 04:56 PM »
and you get to drink it how and when you like - ensuring that the product is always at optimal freshness!
"The crema which dissipates is not the lasting crema..."

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« Reply #23 on: 24/10/2016, 08:30 AM »

When monitoring your roast in the early stages you need to look at your turning point - the moment when the rate of temp drop has "bottomed out" and the beans start to heat up and your initial ramp is underway.

Turning point (TP) ranges vary depending upon the roasting device, charge temp, bean mass & type, energy source (heat) and the environmental conditions such as ambient temp of beans, etc.

For roast devices that use some forms of conduction and convection, e.g. a drum, etc. you should be trying to look for a turning point between 2:30 and at perhaps 3:00 mins.

I find TP calcs a highly valuable indicator on whether I've worked out the correct ratios of green kg's, charge temp, energy applied, drum speed and airflow. So important is this for me that when roasting a new bean I will do some very quick sums in my head based on experience and try to run ahead of the profile curve to predict (or visualize) how the bean will behave in the chamber during the execution of the roast. It's a particularly fun game for those times when you are shackled to the roaster for 11hrs straight  ???.

Since this thread had some recent activity, thought it'd be ok to comment....

The biggest influence on "Turning Point" is actually temperature probe.  Think about it - the beans are at 20*C for example, ambient temp.  The roaster temp probe says it's 200*C in the roaster.  If the probe had no thermal mass and accurately measured the bean's surface temp, as soon as you loaded the beans in the roaster it'd register 20*C.  But the temp probe's thermal mass and the fact that it's not measuring the bean temp, just the temp around the beans, means that the temp shows a decreasing trend - the beans are sucking a bit of heat out of the probe over time.  A low thermal mass probe (eg thin), it sucks heat out faster, a higher thermal mass probe sucks less heat out so takes longer to get down to the same point.   So now we have two probes that show a different "apparent decreasing temperature" rate or slope of the graph.  You have beans that are taking on the heat in the roaster, and are coming up in temperature no matter what the probe reading says.  At some point, you have these two factors coming together, which forms the turning point on the graph - but nothing, besides the reading, is "turning"; the beans have been increasing in temp all the way along. 

This is why comparing my turning point and your turning point is yet another "pointless" thing to do (pun intended).  I do agree that all the other factors mentioned above like energy input and green weight and charge temperature, that influence the apparent TP on my roaster help me understand my roaster and improve my roasts, but the time it takes for me to reach TP is not transferrable to your roaster or your probe location or your probe thermal mass. 

The most important point is that TP is not real - it's just a representation of what is going on when measuring beans through a medium that doesn't transfer heat well.

LeroyC

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A basic roast profile guide for home coffee roasters
« Reply #24 on: 25/10/2016, 03:52 AM »
Since this thread had some recent activity, thought it'd be ok to comment....

The biggest influence on "Turning Point" is actually temperature probe.  Think about it - the beans are at 20*C for example, ambient temp.  The roaster temp probe says it's 200*C in the roaster.  If the probe had no thermal mass and accurately measured the bean's surface temp, as soon as you loaded the beans in the roaster it'd register 20*C.  But the temp probe's thermal mass and the fact that it's not measuring the bean temp, just the temp around the beans, means that the temp shows a decreasing trend - the beans are sucking a bit of heat out of the probe over time.  A low thermal mass probe (eg thin), it sucks heat out faster, a higher thermal mass probe sucks less heat out so takes longer to get down to the same point.   So now we have two probes that show a different "apparent decreasing temperature" rate or slope of the graph.  You have beans that are taking on the heat in the roaster, and are coming up in temperature no matter what the probe reading says.  At some point, you have these two factors coming together, which forms the turning point on the graph - but nothing, besides the reading, is "turning"; the beans have been increasing in temp all the way along. 

This is why comparing my turning point and your turning point is yet another "pointless" thing to do (pun intended).  I do agree that all the other factors mentioned above like energy input and green weight and charge temperature, that influence the apparent TP on my roaster help me understand my roaster and improve my roasts, but the time it takes for me to reach TP is not transferrable to your roaster or your probe location or your probe thermal mass. 

The most important point is that TP is not real - it's just a representation of what is going on when measuring beans through a medium that doesn't transfer heat well.

So it's all relative and it pays to know your equipment. If you know how everything fits then I guess every part of your roast profile is useful, it's just specific to your set up.
I love coffee. It's as simple as that.

CoffeeParts

 

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