My roest experience and what I understand Coffee talks
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Member 37 posts Denis S Member 37 posts
Denis S
Hey there. In June 2022 I got my Roest. I had some basic knowledge about roasting as I had 2 air roasters with tc4, 1 popper and 1 gas drum roaster (rostbiene-De) with gas manometer and a strong kamel cyclone (Korea).
 
I really wanted a small electric roaster that can replicate and roast automatic by itself after a certain profile. I also needed a small batch roaster so I can try many batches or roast many different beans.

Since June to now I reached 350 roasts and since last week i've opened my small roasting business (mainly selling single doses/small doses to friends, filter roasts from microlots).

At the beginning as some of you I went all over the place with profiles, I tried many profiles without understanding much and cupped every single roast more than once, in comparison one to another to understand what went good or what went bad.

To not be biassed I took my roasts (from good beans- nordic approach ethiopias, some kenya, and high grade colombian) to my local roaster in Bergen (BKB) and we would cup them every Thursday, with more people, some of the roasts even compared with their production roasts from the same bean lot. I put a lot of pressure on myself to learn and roast better and better.

I did try a variety of things, from standard profiles (Roest, Tim Kenya, NA, Sucafina, 50g profiles, Matt profiles) to some weird stuff I experimented with such as low rpm/high ET profiles, high doses, short or long roasts.

After several tries, I've found the sweet spot for what works for me and found out some tweaks and answers on why some things happen:

- why does the BT sensor flatten or goes down in FC? because the sensitive thin probes, it can be but I believe the answer is that in a small roaster you rush throw drying and you have rezidual water inside left, that at FC some of it will burst out and cool down the chamber. So I found out that by extending the drying from 2:30-3 min to 3:30 up to 4min+ for big beans will always bring me with a upwards BT no matter what beans, even kenya.

- keep the fan steady, as variations in fan will modulate the heater input, it will cool it or add more heat to it. The same thing for rpm, rpm can play an important role for the conduction added to the beans from the thin drum but also the conduction added between the beans. If you lower the rpm the beans will touch more, creating conduction between them, so if you want caramelized beans on the outside, lower the rpm. 
Do not play with these parameters near or at FC. A higher rpm increase near FC will give you a "flick" on the graph, just because when you accelerate the rpm, you agitate the beans way more so the hot air can reach more between the beans, creating a burst in temp in the BT.

- to get a good clean super sweet roast I pay attention to bean humidity and end roast weight loss. For example an ethiopia is 10-10.5% humidity and end weight loss will be close to that. That tells me the drying was done properly, and i'm not over roasting it, i'm also not leaving behind a lot of chrologenic acid, or left water (to me those kind of roast always in cupping taste a bit like over-extracted green tea, or vegetal/astringent, it's not a pleasant acidity.

Keep in mind that the default profiles for instance Roest is made by the team so that every one of us has a change at a good starting roast result. I live 15 m above sea level but have friends with Roest at 2000masl. We also have different humidity levels in the room (I started to roast with a auto humidifier to have a constant humidity as I found out the roaster dries the room a lot fast after 10 roast from 64% to 42% humidity). We also have different voltage power at the electrical plug (a reason why I prefer ET profiles to power profiles).

In the end this is what works for me (you have to adjust the max ET based on your beans size and altitude- all profiles are for 100g):

This is for a small bean natural- Ethiopia:

https://front.roestcoffee.com/shared_profile/f3f698e0-b361-4f43-993d-17395005b8fc/

The idea behind why it should work like this. Ethiopia has small beans, and small beans roast faster. I found myself often underoasting these because they crack fast on a normal profile under 5:30 mins, so I extend the drying and develop them 30-40sec max with a weight loss of 10.5%. The ET increase in dev is small, you cannot add a lot of heat there because the sugars in the naturals will burn on the surface of the beans easily. You can't really drop the ET either because they are small and have a low mass compared to other beans. Dropping the Et gave me dull/flat roasts even if I increased the development.

Adjust the last 2 points based on your altitude: mine is 15 m above sea, try adding 2 C and see how it goes, land with a low ror.

This is how it looks:

F7377496-295A-43DF-A968-14C4D3C1218F.jpeg

If I would have a washed coffee with small beans I would aim for a bigger increase in ET after crack and a higher Ror entering FC.

Now let's move to a funky big bean colombian (Col Quindio natural carbonic maceration gesha). Huge beans.
Humidity in these beans is above 11.5%. They have a lot of funky flavors and bare sign of heavy fermentation (the greens are multi-colored). The beans are extremely sour so roasting fast is out of the question.

Because the beans are big I want to extend the roast more compared to Ethiopia, but not too much as I dont want baked/flat coffee.

Here is the profile for it:

https://front.roestcoffee.com/shared_profile/5b5b8e39-75cc-48d9-a98f-9011441de05b/

I dry the beans more color change is above 4 mins,  I then go up to the max ET of 243C way before FC and immediately after FC I'm jumping down in ET. These type of beans will take off into development if you dont bring the heat down. They are also big beans and can yield a lot of stored heat inside them, and in the roaster (100g of colombia is not the same mass./heat in the room as 100g of ethiopia)

This is how a roast looks like:

1AAD38CD-D094-4585-821A-0B77DA3AEB7D.jpeg
IMG_20220927_111214.jpeg
There are some key-points I found out that need to be accomplished to have a good roast, beside the drying phase that needs to be long enough you also need to figure out what is the best delta between ET and BT. I've seen many profiles where the ET would go 30-50 C above BT, in my opinion that wont work taste wise. Because you are inserting a lof ot heat into the beans and they wont be so glad to take it. Rushing drying will give you a more acidic coffee but also a more rich in "green tea" taste and astringency of unripe fruit. The taste is also tea and not high in sweetness.  Many people complain about air roasters that they lack sweetness, I think it's exactly because of that reason, most of them rush throw drying and finish it in 2-3 mins tops. 

Roasting is difficult and there are no guidelines as each roaster is different, but together we can understand more, if we share and try stuff. Feel free to try, ask or add anything.
Reply 9 0
Denis S Member 37 posts
Denis S
So, another coffee another chapter, another learning curve. The written above applies for me on naturals or fermented beans, either ethiopia (2100masl) naturals or colombian naturals (1700m) super big beans. Bean size (density) plays an important role on profiles.

Now let's move our attention to something else, washed. In this case I got this Peru washed Fidel Huancas yellow bourbon cup of excellence 4th place.

IMG_20221001_115511.jpeg

At first, the beans look small, the aspect is dense, like you see on a washed ethiopia. I've tried some of the above profiles or a 6-7 min profile with really bad results. Uneven beans, flat taste, baked roasts.

I then revisit the forum, went again with reading Matt's profiles, Sucafina, Albert and Bazej posts on the blog.

So I came up with the power profile and see how the coffee behaves in shorter roasts, since longer roasts were horrible for me (either long or short development).

Here is my first short roast attempt with 100g:

You can already see the typical washed "kenya" behavior like, when you enter the development with a short previous phases and the BT sinks and the crack rolls. I was already frustrated because of this.
CAB2B773-C337-4D5D-A771-2D0E8C9320F8.jpeg

Cupped it twice and brewed it twice, it was showing flavors that were not found in my 6-7 mins ET roasts. more acidity, not as flat, but still harsh and green. Increasing the development time would not help here as I was already loosing 11% weight loss, and the humidity of the beans were 10.5%. I believe for a good  filter clean roasts you must land around the humidity percent of the beans.

So here is the winning profile, cupped 5 profiles from 50 to 120g batches, between 58 to 68 rpm, with different development times.

This was the clear winner and I would play only with the development time based on taste preferences.

https://front.roestcoffee.com/shared_profile/21a40b8a-939a-4cae-b369-4c16d207fb92/


119g because after weight loss (10-11%) and sorting out quakers and shells i'm left with 101/102g of beans.
- disable the FC detection feature as the noise made by the beans spinning at 69rpm will fake some cracks picked up by the microphone, better disable it.
- develop the beans to your liking, I mark FC only after I hear the crack rolling and in my case it's after 3 min 30 sec. I developed mine 32 sec and it seems enough
- a faster rpm (69) will develop the interior of the beans much more and faster, so do not get tricked that the beans can't be developed in such a short time. 

A key component of this type of roasting is to have the drum temp under control. I start with 200C -220C charge but i'm cooling my drum temp between batches with a cooling profile and I start each roast when my drum temp is reaching 120C (the beans are small, for a bigger bean I would wait to 125/130C).

The profile looks similar to Matt's power profile. it's extremely fast, but the beans are developed inside.

BCB4BA8A-26C4-46C1-90D7-BDB1C8231169.jpeg
IMG_20221001_214207.jpeg
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Per Junior Member 6 posts
Per
Thank you Denis for sharing this. It's very helpful for me as a new Roest roaster!
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Denis S Member 37 posts
Denis S
Hey there. I upgraded my roaster with the new inlet kit (thank you Roest team)  and slowly moved from 100g profiles to 120g and now settling at 150g batches for some time. The roaster can do 200g but I feel 150g is a good number to do and let's you run higher rpm is that is what you want. With 200g you will have to reduce a bit the rpm as some beans will get pushed out to the exhaust. 
 
150g batches gives me more accurate data to the graph compared to 100g batches. Roasting 2 batches of 150g at once gives me after a weight drop of 11-13% and some sorting ±250g of beans (so a bag of coffee). My focus since january 2023 moved from naturals and anaerobic processed beans to mostly washed high density beans.
 
I roasted some and I came up with this profile that I made for 150g of beans (it works for kenya, ethiopia, colombia):
 
 
To help people who dont own an inlet temp I created a power profile based on my inlet temp roasting, you will have to adjust up and down to get your FC at 5-5:30 min mark:
 
 
Batch size: 150g
aim for a minimum of 60-65 sec development (this will give you above 11% weight loss) I prefer sometimes a bit longer dev even 70 sec.
The first crack should be happening in the 5-5:30 min mark, if the first crack is not happening there then you should increase your points for the inlet or power profile to adjust it for your altitude (i'm at 20masl) or your voltage at the plug (got 240V).
 
 
Here is how a roast looks like with this, ethiopia washed  greens from Kaffa Oslo:
55A7B18F-6E78-44AB-A1FC-3694048658F8.jpeg
 
73 sec dev time, 11.27% weight loss, 115 agtron gourmet scale color
 
For any other beans that's not washed high density Aris made a nice profile that he shared on roest discord. I tested this profile on several beans (El Salvador geisha anaerobic 300h fermented, colombia natural, colombia honey sidra) and it works really well:
 
 
batch size: 150g
mentions: after you enter FC you must increase the air by hand from 32% to 90/100% in 30-40 sec. 
FC should be at around 7-7:30 mins here (you can extend it to have it a bit later if you are roasting some low altitude not so dense beans- like brazilian). Development depending on the beans 50-60 sec.
 
Here is a roast with it:
 
C6299D30-5F8C-435F-BFA6-9B524720ECF5.jpeg
 
 
 
Dont be afraid to experiment and feel free to ask anything. I'm not claiming that these are the best profiles out there, but these work for me with good results. Clean, juicy and super sweet coffee, and the most important part is there are no underdevelopment taste in the beans, no matter what. Let the beans rest for 2 weeks before trying them. Good luck.
 
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Per Junior Member 6 posts
Per
Thank you very much Denis that you are so generous to share your effort! I have an inlet sensor in my machine so I will try the profile for naturals tonight. It's the first time for me using that kind of profile. The logs look really nice and you say they taste good also so it seems to be a win/win! The bean I'm going to roast is 150g of a rather small natural from Ethiopia that I've got good results from before with an ET-profile I had modified. That was a 100g batch. Exciting!
 
I also want to share this blog from Scott Rao:  https://www.scottrao.com/blog/sample-roasting
 
Per 
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Denis S Member 37 posts
Denis S
When you roast pay attention to your exhaust and ET temps. If your exhaust is really close to your BT before the crack it means there is too little energy left in the system and you need to increase the inlet temp/power.
 
Also make sure you charge at a lower temp (I charge based on drum temp but not everyone has a drum temp) I aim for 125-130C max drum temp or this would be 175C ET±.
 
For most parts if you have too little energy for your altitude (or other reasons) you will see a climbing ET up to 1:45/2 mins mark then the ET will go down, you want it to be either slightly climbing up or remain steady, but in the end the exhaust will let you know if you had suficient energy to crack the beans or not. 
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Per Junior Member 6 posts
Per
I've just tried the inlet profile for naturals. It looks very good. I have tried air profiles and BT-profiles before but the machine seems to regulate much better with this inlet profile or it's the very good profile. I will make some small changes and roast another batch tomorrow. Thank you again @Denis S 
 
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Per Junior Member 6 posts
Per
I made a new roast with the same bean and the same profile as above. Yesterday I forgot to raise fan speed after FC but I did today. I can't see a great difference. At the same time as fan speed goes up also the power goes up. I would like the power to go down instead at the very end. Now RoR flattens after FC. I should maybe have dropped both batches a little earlier. DTR were 20% and 19,4% respectively. What is exactly the reason for raising the fan speed after FC? Color of the first roast was light but not very light on the scale I have. I can't say much about taste as it may need some rest. I will measure the color of the second roast tomorrow. 
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Paul Ahn akc0218 Junior Member 2 posts
Paul Ahn akc0218
Hi, Denis.
 
This is amazing. Thank you for sharing all of this. It made me rethink of how I approach.
 
I was just curious, what kind of Between Batch profile do you use? I'm trying to implement it since roast offers it now, but I'm not sure where and how I should start with it..
 
As of right now, I do it for 5 mins, slowly increasing to my charge temp, but according to what you said on this thread, that might make my starting environment too hot? 
 
So, just curious how you approach it. 
 
Thanks! 
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Denis S Member 37 posts
Denis S
Hei, I learned a lot of stuff since then, and i'm roasting different now.  I roast much slower and with the max power placed in the maillard phase.  The dry is at 3:30-4:30 mins depending on bean, and crack at 6:30-7:30.
 
 
Development is kinda the same depending on bean: naturals 40 sec, washed dense 50 sec. 
 
 
Power profile for washed (works for naturals too):
 
Inlet profile for washed (works for naturals too, if you have a slow roast, for ex: crack at 8+ just increase the top inlet points by 5-10C):
 
 
 
For my machine i have good results at 35% fan and I increase it at 40% after I hear FC. For your youll have to figure it out, might be the same or slightly higher fan (40-50% but not above 50%).
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justkeeproasting Junior Member 8 posts
justkeeproasting
Hi Denis,
 
Thanks for sharing your experiences here! It helps a lot. 
 
Just curious, do you encounter any tipping issue so far, and if so, how did you overcome the issue?
 
I myself have been trying to fix the problem by lowering the charge temperature, gentler heat application, but they don't seem to help.
 
Thanks!
Reply 0 0
Denis S Member 37 posts
Denis S
Hei, many things have changed since then. I moved from roast 100-125g to 170g on all beans. The roasts are more stable and the data is a bit more reliable and there are less swings while roasting.
 
That is one change I made, another one is reducing the inlet rpm from 3400 rpm stock to 3100rpm (in the roasters menu) it just means the airflow during roasting is reduced overall. And after that I roast with a drum pressure meter (but a paper or lighter test at the trier should do it too). I aim to have neutral pressure while I start roasting up to 150-160C and after that I aim to have a slight negative pressure to evacuate the chaff and smoke.  From 150/160C to the end of the roast I manually increase the fan 2 or 3more times, with more airflow during the dev phase.  
 
From testing this lower airflow/and managing the drum pressure better results in more developed beans inside (the beans are bigger in size) while maintaining a more even and lighter color on the outside. The problem is that this drum pressure depends on many things- your exhaust system,  your batch size, air-inlet temp- and other things i dont know about. So my air settings wont work on another roaster, some roast with neutral pressure at around 50% exhaust, and on my unit I need to be at 30% exhaust at start.
 
You can read more about it here, in details:
 
 
Again the drum meter is not mandatory, you can do your testings using a lighter/fire at the trier during a roast and manipulate the exhaust till you see the flame bending just a tiny bit (remember to have your heater rpm set to 3100rpm).
 
Here is just an example of a roast. I changed the inlet based on what I want to get. 
 
IMG_5984.jpg
 
E8F87FA7-EBB1-4519-887A-DF2994B74DF8.jpeg
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justkeeproasting Junior Member 8 posts
justkeeproasting
Hei, many things have changed since then. I moved from roast 100-125g to 170g on all beans. The roasts are more stable and the data is a bit more reliable and there are less swings while roasting.
 
That is one change I made, another one is reducing the inlet rpm from 3400 rpm stock to 3100rpm (in the roasters menu) it just means the airflow during roasting is reduced overall. And after that I roast with a drum pressure meter (but a paper or lighter test at the trier should do it too). I aim to have neutral pressure while I start roasting up to 150-160C and after that I aim to have a slight negative pressure to evacuate the chaff and smoke.  From 150/160C to the end of the roast I manually increase the fan 2 or 3more times, with more airflow during the dev phase.  
 
From testing this lower airflow/and managing the drum pressure better results in more developed beans inside (the beans are bigger in size) while maintaining a more even and lighter color on the outside. The problem is that this drum pressure depends on many things- your exhaust system,  your batch size, air-inlet temp- and other things i dont know about. So my air settings wont work on another roaster, some roast with neutral pressure at around 50% exhaust, and on my unit I need to be at 30% exhaust at start.
 
You can read more about it here, in details:
 
 
Again the drum meter is not mandatory, you can do your testings using a lighter/fire at the trier during a roast and manipulate the exhaust till you see the flame bending just a tiny bit (remember to have your heater rpm set to 3100rpm).
 
Here is just an example of a roast. I changed the inlet based on what I want to get. 
 
IMG_5984.jpg
 
E8F87FA7-EBB1-4519-887A-DF2994B74DF8.jpeg
Thanks Denis!
Reply 0 0
Kaqw0116 Junior Member 2 posts
Kaqw0116
Hei, many things have changed since then. I moved from roast 100-125g to 170g on all beans. The roasts are more stable and the data is a bit more reliable and there are less swings while roasting.
 
That is one change I made, another one is reducing the inlet rpm from 3400 rpm stock to 3100rpm (in the roasters menu) it just means the airflow during roasting is reduced overall. And after that I roast with a drum pressure meter (but a paper or lighter test at the trier should do it too). I aim to have neutral pressure while I start roasting up to 150-160C and after that I aim to have a slight negative pressure to evacuate the chaff and smoke.  From 150/160C to the end of the roast I manually increase the fan 2 or 3more times, with more airflow during the dev phase.  
 
From testing this lower airflow/and managing the drum pressure better results in more developed beans inside (the beans are bigger in size) while maintaining a more even and lighter color on the outside. The problem is that this drum pressure depends on many things- your exhaust system,  your batch size, air-inlet temp- and other things i dont know about. So my air settings wont work on another roaster, some roast with neutral pressure at around 50% exhaust, and on my unit I need to be at 30% exhaust at start.
 
You can read more about it here, in details:
 
 
Again the drum meter is not mandatory, you can do your testings using a lighter/fire at the trier during a roast and manipulate the exhaust till you see the flame bending just a tiny bit (remember to have your heater rpm set to 3100rpm).
 
Here is just an example of a roast. I changed the inlet based on what I want to get. 
 
IMG_5984.jpg
 
E8F87FA7-EBB1-4519-887A-DF2994B74DF8.jpeg
Hi Denis,
 
Thanks for sharing! it's a treasure for a newbie like me.
 
I got my Roest a month ago, I never roast any coffee before, so I tried some profiles to start it but the bean temp sometime it's not reliable as the batch is 100g.
 
So I lower the inlet rpm to 3100 as I'm located near sea level, checked my drum pressure still got no good result on 100g.
 
I would like to tried increase my roast to 170g like you mentioned, if it possible to share your profile on this 170g profile?
 
Manny thanks! 
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Denis S Member 37 posts
Denis S
I have been roasting 200g batches mostly and a few months ago went back to 3400rpm for the heater, as I compared 2 roasts side by side with a controlled profile roasted to the same color and liked  3400rpm better. 
 
With 200g as Roest team has posted, you will need to lower a bit the rpm (i'm at 50rpm) or what I do is put a lifter/spacer on the right side of the machine so the beans pile fall faster before reaching the upper side of the drum (where I think beans can get between the exhaust opening and the propellers. 
 
200g roasts have a better BT readings, more heat stable and once the roasts starts rolling easier to control. The inner development is also bigger on 200g vs 100g. This means my development time is much shorter for 200g.
 
I can gladly share the profile, but keep in mind the machines can be a bit different and we have different taste and greens, feel free to adjust things:
 
200g washed profile:
 
I roast anything washed with this one, kenya cracks at 5:30-6 mins other beans at 6 mins+ (ethiopia, colombia, honduras, costa rica). For the development I like 20-30 sec max or 197-198C BT on my machine. The color is 120-125 agtron (espresso fine grind size) and the beans are ready to drink after 2 weeks rest.
 
200g natural profile:
 
The same as the washed one with a bit less inlet/heat on the last part so the bean temp doesnt take off.  I aim for the same development time here, but the BT will get higher because natural beans get hotter on the outside. I drop at 198-201C.
 
100g profile for any kinda of beans:
 
For 100g I can't rely on the bean temp readings as they are not so accurate and reliable as with 150-200g of beans. This is why I do not use a profile that uses the BT, so no BT/IT here. Instead I use a inlet profile that pushes some energy into the beans up to yellow without creating defects or tipping and then slowly decline the inlet and keep it to a safe value.  The beans will crack in the 5:30-7 min interval depending on the varietal (roasted an el salvador pacamara natural that cracked at 7 mins mark with 30 sec dev it turned out perfect). A kenya will crack sooner, aim for 5-7 min FC time.
 
You have to keep in mind that the beans will get darker tasting after 2-3 weeks, so adjust that to your liking. 
And just to repeat myself again, I am at 3400rpm heater-stock settings with the profiles above. I tilt my roaster because then I have no rpm stalling and there are no beans in the chute with 200g roasts.
 
An example of 200g roast. this one on washed kenya.
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