1200m Rest L2.4 vs K-Logic L2.4

[Sam]

Hi All,

Perhaps, someone on the forum can help me understand what is happening with my Brazil Santos 100 gm roasted to the same level L2.4 using 1200m Rest and K-Logic Classic.

The Rest profile is causing scorching of my beans despite only 20% development. The K-Logic reaches 30% DTR without scorching.

Is it fan speed? It would be nice to be able to compare the fan profile to the default.

Thanks in advance,

Sam

[Geronimo]

Hi

Open Studio up on computer and open roast log file for the Rest roast, then depending what you want to compare, for instance on the Tools menu, you can turn on Compare default and the K-logic default profile will show. Or you can select Compare files on same menu and pull in another file to compare. Can do the same in the fan profile tab if you want.

Both fan speeds for Rest and K-logic default are the same.

Whilst waiting for an official response, there is no harm in bumping fan calibration up a few notches. Or like many are doing, tweaking the fan profile to get the beans circulating more at the start of the roast. Read blurb by Damian under his contributed D-Roast profile. Note this profile as is required a good power supply and certainly worth trying on your beans if you have.

Cheers

[Sam]

Hi,

I didn't see the compare fan profile because they overlap each other. So, it's one variable eliminated.

I'm fine with using K-Logic instead of the 1200m Rest profile. Just wanted to better understand what may be causing the scorching.

I'll read Damian's blurb on the D-Roast profile.

Thx.

[nrdlnd]

I didn't see the compare fan profile because they overlap each other. So, it's one variable eliminated.

I'm fine with using K-Logic instead of the 1200m Rest profile. Just wanted to better understand what may be causing the scorching.

This is complicated. You are not the first saying 0-1200 scorching the beans. @Angela reported a similar problem but explained it that the beans were old and dry. I haven't used either the Classic profile or 0-1200 with Brazilian beans but I've used Steady&Dark II and I can't see any scorching and also no tipping. The profile of Steady&Dark II is similar to 0-1200 Rest as there is a rather slow rise (the Classic profile has much more heat in the beginning). What differs is mainly the fan profile. They start the same but Steady&Dark II has a higher fan speed in the middle of the roast. Could it have to do with this?

Edit: If I understand the dynamics correctly in a fluid bed roaster does a higher fan speed mean less heat at the surface of the beans!? If this is the case does the lowering of the fan speed at the middle of the roast with the 0-1200 heat the outside of the beans more and they become scorched? My hypothesis why this doesn't happen with the Classic profile is that it has more heat in the beginning when it still has a rather high fan speed. I think it could be interesting to use the fan profile from Steady&Dark II with the 0-1200 Rest and see if the problem with scorching persists! It could be that the low altidude Brazilians are less dense and transfer heat slower to the inside and that's why they more easily become scorched. This is only some thoughts that I have and I can't proof that they are correct.

[Wayne]

Good day Sam

I hope you are well ? Thank you for the post question.

The question you are asking is a common one and was asked before on the forum . I cant remember if it was on the 0-1200 REST profile but it was on Tipping of coffee . Nrland is correct , it was Angela who asked the same question and the answer I gave was the conditions of the beans - Age of the beans and not the profile .

Let me elaborate on this . The 0-1200 REST and RTD profiles is designed not to scorch or discolour the coffee .
Low altitude grown coffees need to be cared for. Especially at the start of the roast and into drying phase .

Secondly , the age of the coffee will determine how severe that end bean look will be . The older the bean is , the less resistance it has to the swelling effect that takes place before first crack . As the bean swells with gas and CO2 just before first crack , the ends of the bean can start to leak and the intense temperature of the steam can discolour the tips . This is most often a result of older coffee . Scorching or tipping in the start of the roast normally produces a mottled end result . The coffee's contact with heat is exaggerated and will become negatively effected . Mottled , deep craters or swelling points .

Could I ask you , If you have tasted the coffee , how does it taste ? If not , it's ok .

Could you please send a picture of the coffee ?

I have roasted a batch of Brazil Santos - Pictures below . On the same 0-1200 REST profile and same level of 2.4 . Pictures of this batch attached . Oh and the last picture is of a secondary defect - Worm damage . Santos is not the best grade .

In closing , Could it be the age of the coffee ?

I look forward to hearing from you and thank you again .

Wayne

[Sam]

Hi Wayne,

I will post photos when I'm next at home.

I have no reason to think the beans are old. The green beans were purchased from a very busy, high volume roastery nearby, just a few days before roasting.

Assuming the beans are fine, why would beans scorch on the 1200 Rest profile but not on the K-L profile?

The K-L profile applies more heat earlier in the roast and runs shorter but achieves a 30% DTR at L2.4. The 1200 Rest profile delays First Crack and reaches a 20% DTR for the same level.

This is more for my understanding than anything else.

Thanks,

Sam

[Wayne]

Hi Sam

Thanks for the input .

On DTR , Profiles and implementation of heat on the coffee will aid in determining FC . Apply more heat and you may get an earlier FC . The 0-1200 REST is an extended profile and was designed to soften the blow of adding great amounts of heat to a very porous low altitude bean in drying phase . Generally great amounts of early heat may cause tipping and scorching .
We are looking to eliminate this with this profile . With shaping the heat application , the roast will be become extended making 2.4 on Classic different to 2.4 on 0-1200 REST and increasing the overall time of the roast for the default medium level .

So in theory , coffees like Santos and other low altitude grown coffees should tip and scorch when roasted on high energy impact profiles like the Classic or the 1500-2000 REST / RTD .

I cannot tell you why this is not happening on the Classic .

On the green . The only reason why I am thinking the coffee could be old is the fact that we have determined this to be the case with Santos before . I have roasted and currently roasting Santos with the 0 - 1200 REST profile and had no issue .
I have last years Santos that I get directly from a green bean broker here in Auckland . I know its last years and not 2018 crop . The current Santos year is only being picked in October . This is generally when Santos is picked .

We also know from Santos in general that it is made up of different farms brought into blending houses and traded out of the port of Santos . It could give you a mottled look at lighter roasts , even at a medium or high roast - Hence why I ask what it tastes like . Scorching and tipping will generally give you an ashy , chary flavour at that light- medium level .

Could I do some more work on this please . Could you please send me pictures of the coffee and a log . This way , we can clear up that we are looking at the same thing .

I would then like to go and pick up some santos from a roaster and test roast these samples on Classic and 0-1200 REST .

Id love to compare notes with you on this , this week still . I'd also like to make a suggestion , Perhaps try the 1200-1500 REST profile . See if this has the same visual effect .

Thank you again Sam for the post and the reply . Looking forward to getting to the bottom of this .

Regards

Wayne

[Sam]

Hi Wayne,

I have attached pictures and logs of the Brazil Santos at L2.4 with both the 0-1200 Rest and the K-Logic Classic profiles.

In the interest of transparency, I had already picked out the worst of the blackened beans from the 0-1200 Rest roast. Perhaps, a dozen or so beans have been binned.

The Brazil Santos is my go-to green bean when I want easy predictable results from my roasts. I have had reproducible and consistent results with Brazil Santos using the KL profile at various levels. It's my reference bean, hence, my interest in understanding why it doesn't respond predictably to the 0-1200 Rest profile.

Cheers,

Sam

[nrdlnd]

On DTR , Profiles and implementation of heat on the coffee will aid in determining FC . Apply more heat and you may get an earlier FC . The 0-1200 REST is an extended profile and was designed to soften the blow of adding great amounts of heat to a very porous low altitude bean in drying phase . Generally great amounts of early heat may cause tipping and scorching .
We are looking to eliminate this with this profile . With shaping the heat application , the roast will be become extended making 2.4 on Classic different to 2.4 on 0-1200 REST and increasing the overall time of the roast for the default medium level .

So in theory , coffees like Santos and other low altitude grown coffees should tip and scorch when roasted on high energy impact profiles like the Classic or the 1500-2000 REST / RTD .

I cannot tell you why this is not happening on the Classic .

Hi Wayne,

I think your theory that it has to do with the beans is correct. My theory was that it could have to do with the fan profile. I thought the fan profile from Steady&Dark II could give another result in respect to roasting defects. I have just made two roasts with a Brazil Dolce Diamantina that I think is a middle quality Brazil bean. It tastes usually very good and it's from the 2019 harvest. I made one with the original 0-1200 Rest and the other with the fan profile from Steady&Dark II merged. Both at L=3.0.

The two roasts are very similar medium dark and without any apparent defects. Evenly roasted and maybe a very minimal tendency to tipping (that I think is normal). I think DTR wasn't very different when I look at the log but it was more difficult to hear 1C on the original 0-1200 Rest. DTR was probably longer on the modified profile at around 23% as 1C came earlier and was more distinct and easier to hear. Roast length was the same at 12:20.

My experiment doesn't help Sam with his problem but my theory was wrong that the problem had to do with the fan profile.

[theiguanaoz]

Hi All,

Perhaps, someone on the forum can help me understand what is happening with my Brazil Santos 100 gm roasted to the same level L2.4 using 1200m Rest and K-Logic Classic.

The Rest profile is causing scorching of my beans despite only 20% development. The K-Logic reaches 30% DTR without scorching.

Is it fan speed? It would be nice to be able to compare the fan profile to the default.

Thanks in advance,

Sam

Hi Sam, try a 120gm batch and see how it goes. I recall someone saying here that smaller batches can sometimes cause the beans just to spin, not necessarily bubble, with smaller amounts under certain conditions.
Newbie here myself, but I would imagine the beans not bubbling up and around would mean that some beans more than others a) stay closer to the heat source, and b) in contact with the chamber wall.

Purely theoretical, but the softer start of the 1200m profile might be causing that. There is a chance a larger batch might see the air force the beans to move differently.