Hi everyone- I am hoping to get some wisdom from the more experienced roasters. I built a recipe two nights ago for 400g of an Ethiopian Suke Quto from Sweet Marias. My goal was to hit FC at about 8 minutes and to get 20% development time. I ran the recipe and it worked out perfect for what I wanted- FC at 7:52. I was super excited and went to bed feeling very proud of myself.
The next day I went out the shop to roast another couple of batches of the same bean using the same recipe but I had very different results. The second batch I marked FC at 6:36, but I really started hearing some cracks around 5:45. I modified the recipe by reducing the power at lower bean temperatures (dropping from P6 to P5 at 340 instead of 350) to try to slow it down a bit more. This time FC started at 5:21, so even earlier.
I cannot figure out what would be causing such different results. I am roasting indoors so at the environmental temp is stable. The humidity was very similar. Both days I had preheated the roaster for 30-45 minutes before starting the first batch so it should have been fully up to temp and stable. I cannot think of what else it could have been and would love some input and ideas. I know that using recipes is never going to be set it and forget it, but I wouldn’t expect FC to come almost two and a half minutes earlier when roasting the same bean at almost the same power settings.
I am new to the Bullet roaster also, but I like this kind of sharing, thank you. The only thing I notice is the change in Power and Fan in the second phase into development. It looks like these adjustments effected your ROR to level off instead of decreasing, especially go into First Crack. Was the environment humidity and temperature different?
The BTemp when you charged the roaster each time was vastly different- the 2nd roast is about +45F° higher than the 1st roast. When you preheat you have to pay attention to BTemp as well as ITemp. ITemp is managed by the roaster but the operator has to manage BTemp at charge and your only control is time and/or the bean chute plug.
Keep in mind BTemp is most influenced by the face plate where the probe is mounted. Raise the face plate temp and you raise the BTemp at the same time. Once the drum is charged , BTemp is most influenced by the beans.
Exactly what bab said. The only time your roaster was properly preheated was at the third roast. You might want to dial down the PH temp and not charge the beans as soon as it reaches your set temperature or says “charge”. For 400g you should try somewhere around 420-430f as your preheat temp and go from there. For the first roast let the PH run longer. I don’t know how it is with the R2, but it should be similar. On R1 at least 40 minutes before the first charge.
As @bab said! When I roast, esp the first roast, I look for the BTemp to stabilize at around 400F for at least 10 mins. To get there it’s at least a 20-25 min total preheating time - my ambient temp affect how long, as summer vs. winter temps inside my house is a good 10-12F difference. I roast 1.1kg batch and PH at the highest temp in order to get the 400F BTemp reading.
Thank yo so much Bab- you are exactly right! I have only been paying attention to the ITemp and not at all to the BTemp.
One of the reasons I was excited to buy the Bullet was the community. It is great to be able to get feedback from more experienced and knowledgeable people! Thank you for taking the time to look at my charts and tell me what I was missing.
From my own experience, I have found that sometimes my roasts that go wonky can give me insights into how different parameters change the flavor of the roast.
My main rule is: How does it taste?
It might be interesting to do a side by side cupping comparison and note what the differences are between those 2 roasts.
Hey there,
From what I have read and gathered from fellow roasters, it is the first roast of the day or batch that is usually finicky. What I have been doing is roasting the first batch of the day as a dark roast to get the Bullet up to prime operating mode, as we know origin flavor profiles are not as distinct in a dark roast, so less chance of undesirable results.
Happy Roasting!
Contrary to the general thought that the first roast is the most finicky, in my case, where I do 5 B2B roasts of 1.05KGs at a time, my second roast is the one that needs most attention. The first preheat extends to over 20mins, and that, as I have noticed gives quite a bit of thermal momentum to the roast. The preheat times post the first roast are much shorter but the second roast itself needs a bit of tweaking with regards to P and F.
By the third roast the drum has heated up well and matches the momentum of the first roast. With my fourth and fifth roast, with the chaff filter partially clogged, I need to up the F one notch to increase air flow. With these tweaks, have managed to more or less roast uniformly across the five roasts.
