@kafcafe Hi, So here’s what I get from reading your Colombian curve:
Charge temp seems high. How about 195-205 and go for a slower convection-roast?
The ROR is steep between 2:44 to 4:24, then when P5 adjustment gets felt it looks to recover to a shallower curve. Perhaps your bean missed some early development in this phase?
D9 is fast for 350g. I go for D8. Found a calculation of beans tumbling in a drum and the recommended speed equates to D8 on our Bullet.
Can you put the Yellow Point and First Crack times on your curve pls? These can be added in the settings in RT3.
Colombians are known to have bright acid and fruit at lighter roast. I like full-bodied coffees with lingering chocolate and caramel flavours, so i’d go long into the development and drop before second crack. Btw, I found this link, which explains the nuance of the Colombian bean: https://www.sabores.co.za/2019/07/22/guide-to-colombian-coffee/
350g would be my min batch size. I’ve read of some folks doing 200g batches. It looks like another different technique because of the smaller bean mass and different exothermic conditions. I’m accepting it’s going to cost me a bit of waste to begin with to learn how to roast 350-700g batches! Where do you buy your cheap Brazils from at $6? Give me their number!
Anyways, hope I haven’t confused everything for us…
The charge temp depends of the qty of beens used, their density and % moisture and the profile we try to achieve. I have read also that the altitude you are roasting might have an influence too. I guess it is the knowledge experience will eventually give us.
I think the end temperature tells us the type of roasts (given probes are precise). I think once you know the bean, using IBTS or the bean probe isto your choice and maybe i would use the one that is the more constant with a specific bean. Anyway people with more experience might have another (better) explanation.
I am pretty sure that the RoR diminishing after RoR reach a peak is more important than the rate at which it diminishes per say. However if the decline is too steep, you will stall the batch (ie reaching a RoR of 0 before the fc or before the beans have time to develop). That being said i believe more into my taste buds than into curves. I just noticed after 4 years of roasting with the Gene cafe that everytime i would observe a constant declining of the RoR the coffee would taste very superior, top notch! With the Gene i noted the temp each minutes which brings me to your point 4.
Other might have a different opinion but I looked into my 4 years log book roasting with the Gene, and all the top notch roasts had declining RoR until the end. Of course the RoR with the Gene is not an almost instant RoR like with Roastime, But taken at each minute RoR of top roasts always declined with an end RoR of 1 or 2 (Gene is not precuse eniugh to know). looking at your picture minute per minute the RoR at minute 4 is higher than at minute 5, 5 higher than 6 but 6 not really higher than 7 and 7 not higher than 8. When i would get that with the Gene it would give a dull cup whatever the color of the bean.
Thank you for your observations on the last post. I agree that 220c is a high charge (i think) but i just followed the owner manual recipe blindly without trying to adjust anything (same for the D9 + in the manual they say to put D9 for the first 10 roasts but i agree D8 is probably better). Today i did not roast but did cupping of all the roasts i did for the last two days. It turned out that the decent cup improved a lot in 24h. To me it is still not enough developed to my taste (as it seems to be your taste too) but at least it tastes coffee and the mouthfeel is richer after 24h. I suspect it would turned better as the crushed beans under my thumb had a good smell right after roasting.
Next time when i roast i will put the yellow mark, in fact i succeded to roast a very good cup with 200g of the columbian, powerful coffee mouthfeel , vanilla, hazelnuts, sweet caramel finish, 0 biterness, the kind i was able to do before the bullet. I am so happy! I will post it tomorrow. I charged it at 160 (or was it 165) cannot see it now on my phone. Frankly if i can replicate that i will be very happy! It was the last batch of the day, so the drum was at 160 but after many roasts at higher temp charge. You will see a constant decline of the RoR. charging at lower temp gave me a slightly longer yellowing time to fc (than the missed batches). However the ratio development is higher than 25%. Not sure of this ratio importance.
I live in Canada and among others i am buying from this place for the last years. The eagle brazil espresso is 6.12$/pound for 2 pounds. This is not the best brazilian i have had (supplier sometimes had small farm beans from minas gerais that are amazing but more around 12-13$/pound):
So I looked back at the curve for the first roast and I agree that the RoR is probably too steep from 2:44 to 4:24 and I think that is what prevented to have a significant decline just before the fc, from min 6 to 7. So it is not really declining between 6 and 7 but after fc it is generally declining. Not sure how to “fix” that. Maybe by turning the fan to f4 instead of turning the heat to p5 would trigger a less steep decline…Anyway, the general trend is downward and I think this is why the roast still taste good (but not as great as I would like).
In roast time the yellow point and fc points are showing but not in roast world. However in roast world you have this bar above the graph that indirectly tells you the YP and FC.
. But is there a way for the graph in roast world to directly show those points on the graph?
Anyway here is a screenshot from roastime (is there a way to directly cut and paste the graph in an other way I did? I did a print screen + paint to get it here:
Thanks @bradm, I guess that’s how I interpret things like heat transfer! Also, appreciate the link to seasoning beans tho I’m not sure they’ll deliver to UK.
Btw, I’m posting an update on the rested Mo soon beans now too…
@kafcafe Hey Charles, I am ordering some Columbian and would like to try your 200g profile if that’s ok? Can you post it up soon?
I can edit my roast profile in beta.Roast.World (see photo) that then allows me to adjust the yellowing and FC markers in the time boxes. Try that and see if they show on your profile.
I’ll add new photos of my Monsoon beans in a minute too - got some interesting updates to share!
So This is the image of the first 200g batch success with the columbian supremo (got few scortch, 6 of them on 200g not too bad) but taste is excellent, with slight bitterness but at least it tastes good strong coffee):
this is the image of the playback, I stopped it before the other one and the taste is even better with less scortch ?(3 only and the beans are not as dark) (my wife thought that was really good and comparable to what I was able to do with the Gene):
I also tried the same recipe doing playback (playback works very well!) with Peruvian but it was less developed (however the bean smell very good so I am going to wait some degassing before judging). I think I have a basic recipe that works for dark roast (or at least darker profile), not sure if I really heard the 2nd crack and will try to improve from there. Also I notice that the color of the beans are not always a sign or success/failure. I started a post on smell.
here are the beans of the columbian playback (just tasted it again and I am very happy!):
The playback recipe (which should be the same as the original “colombie dernier”). Let me know if it works for you. I think you can access those under my pseudo Kafcafe. Roast World
@kafcafe Charles, interesting curves you have there and the beans look quite dark IMO. I prefer a lighted roast, though am finding that the dark roasts seem to mature well during resting. Mine now have oils sweating out that is bringing a dark chocolate kinda jammy fruit bitterness to the cup - I’m more pleased with these results now!
Here are the pictures of them now: you can see some oil spots where my thumb is.
@wngsprd a quick update for you: I’ve kept these three roasts in airtight containers now since roasting. Roast 2&3 have both started to show oil spots. And they have all developed a dark chocolate smell. Truth be told, they are both very bitter as espresso, which is tolerable with milk added. They don’t have a full flavour - maybe a hint of chocolate and tobacco. Charles (@kafcafe) has been sharing his analysis with me and I’m looking forward to roasting this weekend to try some of his tips - check his feed below. And what have you been roasting recently? Share some curves with us?
[quote=“kohaii, post:31, topic:4072, full:true”]The power delivered to the induction coil is the same for each power setting (P0 thru P9) for either the 120 VAC or the 230 VAC power board.
sooo
do i get 1550w at p9 at 215v and at 230v is it just drawing more current at lover v or?
my e cig i can run it in vw og vv the resistence is the same
i hope u understand what i am thinking, my english is not that good
Your English is ok… I misinterpreted what you asked instead of just trying to answer the question. Sorry.
And it’s a really good question: how well regulated is the output if the power board of the Bullet when the power line varies from 200 to 240 VAC. That’s something @jacob will have to answer. The Specs in the on-line manual say “200-240V, 50-60 Hz”. The maximum power required is 1500W while the maximum power delivered at P9 is also 1500W- probably not possible since there are losses in getting from the power line to the 21 kHz output of the power board.
Hi All,
Been busy roasting. You can find my roast curves in RT - my User id is scottwaugh. Pleased to hear any feedback you kind people have for me to improve.
Keep getting baked, roasty flavour instead of anything enjoyable. Roasted four sample batches last night and will roast again tonight.
Here they are for your critique:
Looking at your roast curves, the IBTS temp flattens out at first crack. That indicates the the ROR is near zero, which will produce the baked flavors you are tasting.
Several people have noted that the ROR reported by the thermocouple (‘Bean Temp’) diverges from that recorded by the IBTS sensor, and I personnaly choose to belive the IBTS.
Below is a recent roast that shows the divergence between the Bean Temp ROR and the IBTS based ROR. The gap opens up right around FC.
