Coffee roasting profiles

[Franciskoh]

Dear all coffee roasters, not sure there already has such discussion on roasting profiles in this forum before, but I think it would be an interesting topic for veterian coffee roasters that willing to share or clear doubts that some roasters encountered in their roasting profiles.
I come to know that there have 2 school of taughts with roasting profiles at the edge prior to 1C; one is reduce heat source but the other is increase heat source while marching through the 1c, both ways are workable or one way is better than the other?
Hope to see your generous feedbacks

 

[John P]

Franciskoh,

I can give you my basic perspective. Much also depends on roaster being used, size of roaster, size of batch, your particular climate or if you are in a climate controlled environment...

Profiling your roast may mean that both methods are correct. It depends on three things.

1) What is the structure of your bean? SHB, soft bean, large and porous (Margogype, Gesha, Pacamara), peaberry, etc.

2) What roast? City, City+, Full City...

4) What specific flavor elements are you targeting from said bean. Florals? Fruits? Berries? Nuttiness? Chocolates? etc, etc.

So in the first two stages of roasting, the drying phase and the roasting phase (third being roast development) it also depends on how you complete those phases. In 1C, you are in phase 3, which is all about exiting phase two, but it depends on how each stage of the roast was managed as well. At roughly 367 F (186 C), coffee changes from endothermic to exothermic, and it's how you manage the application of heat at this juncture respective of bean type and final roast that will determine the resultant success and/or flavor in your coffee. I tend to be gentler with the heat on softer beans (first example) and a bit more aggressive on harder beans (second examle). It's also about a decreasing increase, so where your RoR is X, it may be x-3, and then x-5, x-8, etc. until you finish.

 

[blightyed]

Hey Franciskoh,

This is a big dilemma I've been faced with recently - It's come about when roasting a Natural processed Ethiopian. I've tried both ways and picked up some small differences. But the thinking must be, by pulling back the heat at 1st you will stretch it out a little longer - lengthening 'development time' and perhaps helping to develop some perception of body. Keeping the energy up, you may get a shorter crack which can help highlight some of the acidity of the coffee - enhancing fruity notes.

When approaching the coffee I have in mind the attributes of the particular coffee based on process and region. In this case, tropical fruits, berries and a big body. My preference is to have the fruits jump out in the cup, I love a natural that packs this crazy, funky, fruity punch. So I want to aim to keep my roast on the light side, highlighting the acidity, which helps bring out those fruity notes. In doing so, I am sacrificing a bit of body, because you tend to develop body as the roast gets darker. (but you can develop body earlier in the roast too, by stretching out the drying phase).

So there isn't really a definite answer to your question. I'm only going to say that it depends on what you want to achieve from your roast and what coffee it is. What I would do is test it out on the same coffee. Keep every part of the roast the same except that bit coming into 1st crack and then cup the coffees the next day to see if there is any significant difference. This is what it's all about, putting a theory to test and seeing what the end result is and deciding for yourself which way you prefer - that's your 'style' or expression as a roaster.

All the best.

 

[Franciskoh]

Franciskoh,

I can give you my basic perspective. Much also depends on roaster being used, size of roaster, size of batch, your particular climate or if you are in a climate controlled environment...

Profiling your roast may mean that both methods are correct. It depends on three things.

1) What is the structure of your bean? SHB, soft bean, large and porous (Margogype, Gesha, Pacamara), peaberry, etc.

2) What roast? City, City+, Full City...

4) What specific flavor elements are you targeting from said bean. Florals? Fruits? Berries? Nuttiness? Chocolates? etc, etc.

So in the first two stages of roasting, the drying phase and the roasting phase (third being roast development) it also depends on how you complete those phases. In 1C, you are in phase 3, which is all about exiting phase two, but it depends on how each stage of the roast was managed as well. At roughly 367 F (186 C), coffee changes from endothermic to exothermic, and it's how you manage the application of heat at this juncture respective of bean type and final roast that will determine the resultant success and/or flavor in your coffee. I tend to be gentler with the heat on softer beans (first example) and a bit more aggressive on harder beans (second examle). It's also about a decreasing increase, so where your RoR is X, it may be x-3, and then x-5, x-8, etc. until you finish.

Hi John, thanks for the pointers on the coffee roasting profile. For your point 2 & 4, i am well aware of these factors but abit tacky on applying point 1 as many more factors involved also like dry process, washed or semi-washed, haha, have to do lots of trial roast to get this point right.
Currently I am using a 15kg Giesen roaster, my customers are generally intolences to acidity, prefer more body with layer of complexities..emmh, so when new batch of coffee stock-in, lots of trial roast again to get the right profile. I usually going for dark roast or at door step of 2c when discharge the beans.

 

[Franciskoh]

Hey Franciskoh,

This is a big dilemma I've been faced with recently - It's come about when roasting a Natural processed Ethiopian. I've tried both ways and picked up some small differences. But the thinking must be, by pulling back the heat at 1st you will stretch it out a little longer - lengthening 'development time' and perhaps helping to develop some perception of body. Keeping the energy up, you may get a shorter crack which can help highlight some of the acidity of the coffee - enhancing fruity notes.

When approaching the coffee I have in mind the attributes of the particular coffee based on process and region. In this case, tropical fruits, berries and a big body. My preference is to have the fruits jump out in the cup, I love a natural that packs this crazy, funky, fruity punch. So I want to aim to keep my roast on the light side, highlighting the acidity, which helps bring out those fruity notes. In doing so, I am sacrificing a bit of body, because you tend to develop body as the roast gets darker. (but you can develop body earlier in the roast too, by stretching out the drying phase).

So there isn't really a definite answer to your question. I'm only going to say that it depends on what you want to achieve from your roast and what coffee it is. What I would do is test it out on the same coffee. Keep every part of the roast the same except that bit coming into 1st crack and then cup the coffees the next day to see if there is any significant difference. This is what it's all about, putting a theory to test and seeing what the end result is and deciding for yourself which way you prefer - that's your 'style' or expression as a roaster.

All the best.

Thank you blightyed, I am really glad to know from you providing precious info on the Ethopian coffee roasting experience. I had roasted several batches of Ethiopia Sidamo (10kg/batch) by maintaining low temp (205t) till 7-8minutes and ramp temp up(215t) at begining of 1C, hold till BT reached 208t and discharge beans..resulting with medium acidity, good aroma, low body, Is this roast profile similar to yours?

 

[Franciskoh]

Dear friends, anyone can share a good profile example for a 13kg batch roast, targeting a minium or null acidity, heavy body with nutty or chocolaty favours, mayb layer of complexity felt in palate? Hope my asking is sensible haha.

 

[blightyed]

That looks similar to something I have tried. I would suggest that 208 is a low temp to discharge a natural processed Sidamo. If it was a washed Ethiopian, that makes more sense - they tend to be more aromatic and floral, big body is not something I would attribute to those beans. You could try to stretch it to 212-15c to see whether that develops more body.

When you refer to complexity, I'd argue that acidity adds complexity to the coffee. The darker you roast, the more you will add body and eventually 'roastiness' to the coffee. In doing so you are sacrificing acidity and potentially complexity, so be aware of what you are aiming for. This isn't to say dark roasts lack complexity, because it depends on the coffee, but I would say you don't really want to be getting into 2nd crack if you have good quality beans.

What coffees are you roasting?

 

[blightyed]

Dear friends, anyone can share a good profile example for a 13kg batch roast, targeting a minium or null acidity, heavy body with nutty or chocolaty favours, mayb layer of complexity felt in palate? Hope my asking is sensible haha.

Sounds like you need a nice Brazil. Maybe something from Indonesia, Sulawesi.

 

[Franciskoh]

Sounds like you need a nice Brazil. Maybe something from Indonesia, Sulawesi.

Yes blightyed, you are right, i am roasting Brazil Santos and Sumatra Mandheling TP.
Discharging Brazil santos at 212t usually result in high bitterness, low body, null acidity and thats all i get on my palate.
Sumatra Mandheling, discharged at 210t, would get low acidity, medium body with some dried fruit experiences..
I do hope to achieve more than this..

I just roasted a batch of Columbian Supremo, with drying for 5.30m ard 220t, reduced to 210t at 7.30m, hold thru 1c and discharged at 208t, taste mild bitter, low acidity and medium body, but i did tasted some dried fruits stuff as well..

 

[blightyed]

What is the final time of your roasts?

Sometimes if you hit your beans with too much heat early on it can add bitterness and astringency to the cup, so be aware of the temperature you drop the beans in and also how much heat you apply right at the start. I get some great results taking my Brazils up to 218 after slowing the ROR during 1st crack to around 6 degrees per minute.

 

[Franciskoh]

What is the final time of your roasts?

Sometimes if you hit your beans with too much heat early on it can add bitterness and astringency to the cup, so be aware of the temperature you drop the beans in and also how much heat you apply right at the start. I get some great results taking my Brazils up to 218 after slowing the ROR during 1st crack to around 6 degrees per minute.

Hi blightyed, my usual final time for a batch of 13kg(green) roast is between 13-14mins. For my Brazil 13kg batch, my discharge BT between 212-215t, never hit 218t before.
May i know your drop BT and did you reduce further before 1C like around 180t@8minutes range?
next Monday will roast a 10kg batch of Thippana, arabica beans from India, anyone have tried profile to share?
Thank you and have a nice day!:grin:

 

[Franciskoh]

Hi, I have not roasted Robusta before, just intended to use current roaster to roast a few batches of AP robustas. Just wonder whether the smell in the roaster drum will stain the subsequent roasts of Arabica?