I’ve been reading around on some of the conversations re: charge temp and decided to test something out this morning using a bean and profile I’m pretty familiar with to see what happens if I drastically change the charge temp.
I kept the roast profile adjustments essentially the same to see how the charge temp would affect the roast curves. My plan is to cup the roasts tomorrow to see if I can discern any differences in the cup based on charge temp.
Initial observations show a similar if not identical declining RoR. With the higher charge temp it appears FC occurs about 30 seconds sooner and even though end of roast time is also the same the development time varies by 5%.
What do you guys think? I’m a bit surprised to be honest that the higher charge temp didn’t affect the roast and its previous profile to a greater degree.
Since you didn’t mention, I’m curious if you roasted two batches on the same day as humidity and ambient temp could affect the preheat temp required.
Also, what about timings for yellowing?
In theory, bigger batches would require bigger differences in preheat compared to smaller batches due to the mass. I will try doing a similar experiment with smaller batches (150~200g) in a few days and post an update.
That’s a good point. I didn’t mention it. No I did not roast them on the same day.
However, our weather has been pretty consistent and my garage doesn’t fluctuate a whole lot except for hot summer and cold winter swings. With that said, you have a point that it may be affecting the experiment. I went back and reviewed the same bean under different conditions (as I recall them) and the profile is basically the same.
I will try again later this week when I roast a different bean but I’ll do two batches with the lower temp, and two batches with the higher temp. I will also mark yellowing to see if there is a difference at all.
I tend not to mark yellowing because it is VERY consistent with all of my saved profiles/recipes. Usually around the 4/430m mark.
In theory, bigger batches would require bigger differences in preheat compared to smaller batches due to the mass. I will try doing a similar experiment with smaller batches (150~200g) in a few days and post an update.
Exactly! This is why I wanted to run the experiment. My RoR curves look pretty good with the 260C charge temp and so I wanted to see how they compared with the higher charge temp both for RoR and taste. I’ll post an update after I cup these tomorrow.
You have a longer development and higher delta temp on the second one. The only way you could know what the difference is would be the colour. I suspect there are differences there. Weight loss could be different too, but the colour is the one that counts.
Good point. I know they were slightly different. I did measure the color of the higher charge temp and it gave me a reading indicating Full City, which was my aim. However, that’s what I usually hit whenever I run ~2:00m (18-20%) development time.
Roasting this morning and did the same bean with the same profile different charge temps. (For reference, 775g Natural Ethiopian) Interesting differences… outside of the weird blip with the 260C charge temp they have very similar declining RoRs. Roast time is a full minute faster with 285C charge. Development is close but also different. Hmmm… we’ll see how they taste in comparison to one another tomorrow after they’ve rested for 24hrs
Color analysis shows the higher charge temp coming in at City+ (65) where the lower charge temp of 260C finished around City + \ Full City (61/62)
Another observation from a different bean that I am roasting at the 286C charge temp this morning to see what happens. It’s a blend (775g of Central American + S. America + Uganda) that usually sees First crack around 9:30m and I finish the roast around 11:30m for a Full City 2:00m dev 212C drop temp.
The first two batches I roasted today went significantly faster. First crack ~8m and finished around ~10m with 2:00m dev time and 212C drop temp.
These times seem fast to me… maybe it’s just because I am accustomed to the previous profile markers and speed.
OK, I finally got it. I was baffled as to why the faster one should be lighter, with practically the same development times, but then I’ve noticed you’ve dropped the heat to P5 on the faster one, while keeping the P6 on the slower one. Usually, you’d push the development a bit further on the slower one to get the same colour. When you look at it, it seems they’re identical as dev. time and DT, But that’s only on paper, or in this case the graphic. The faster one should’ve finished on a higher temp to equal the slow one. As for the roast looking fast to you, it doesn’t really matter as long as you don’t get any roasting defects that can be attributed to you and not the farm. Once you get the fast roast to finish at the same colour, by not making the adjustment, it should be equal to the other one. Last, but not least, have you taken the Morten Münchow course where these things are thoroughly explained? Until proven otherwise, I’ll carry on assuming it’s free for Bullet users.
I haven’t yet! Only because I was looking for it the other day and couldn’t remember if it was Hoos or Münchow. Thanks for the reminder. I was thinking about going back and checking it out. Turns out I was looking for the wrong roaster
What is really helpful in his course is the simplicity of the roasting process and avoiding concentrating on wrong things, such as RoR, end temperature and so on. As far as I’m concerned, this is the fastest way of learning everything you need to know about roasting on the Bullet and getting good results, but also roasting in general. It doesn’t give you a magical formula or recipe, just directs your attention to where it needs to be. I’m not saying that you or I had bad results, but the course is a must, and not just for beginners.
We should also be careful not to throw the baby with the bath water. The logic behind a declining ROR is that heat is gradually reduced at the point when the beans have lost most of their water and are more susceptible to scorching. A smooth and declining ROR probably reduces the probability of scorching and as such is not a bad thing to aim for as long as it is not done for its own sake.
I don’t know how to say this, since people take offense at anything these days. I hope you won’t get this the wrong way, but I think you meant to say facing. Scorching happens earlier, at the beginning.
No offence taken my friend. I called the defect the wrong thing but the point stays the same. Beans are more susceptible to heat related defects later in the roast once they have lost most of their water. At that point in the roast there is wisdom in gently reducing the heat application. There is wisdom in the different roasting philosophies of people like Rao, Hoos and others. The trick is in taking the good from each of their different approaches without throwing the baby out with the bath water by being single minded about any one approach
The approach really doesn’t matter if you get the results you want. As for the defects, I’ve mentioned that above. This course doesn’t really tell you roast this way, or that way. It just tells you what effects certain actions have on the roast. How you roast is up to you. I’d also argue that overthinking it might be the wrong course of action. When you do a SCA course for your roaster diploma, you must match the given colour on different roasters. Nobody asks you how you did it. And if you do match it, it would be really difficult to get defects.
Hasn’t even crossed my mind you were arguing. I don’t know if written word comes across differently or what, but nobody here is arguing anything. Can’t people just express their opinions or is arguing a must? Shouldn’t everyone be entitled to a reply in a healthy discussion? By the way, I don’t even see this as a discussion as we’re both saying the same things in different form.
A few delayed notes based on feedback from some clients and friends who “agreed” to let me experiment on their beans
Client who has a hotel style, super-auto machine said the beans (higher charge temp) tasted great. No discernible differences just delicious. I’m always suspicious of these machine because they’re not drip – not espresso just caught somewhere in the ether.
Friend had an interesting comment about their being a “darker” note to a typical light roast Ethiopian I keep around for him. The fruit notes were still there he said but he noticed a new flavor as well. Based on what he was describing it made total sense that a higher charge temp may produce a more pronounced roasted note in the finished cup. He said it was good, just unexpected.
I’m roasting the same bean for him and went back to the lower charge temp to see what he thinks. Overall, I can’t say that increasing charge temp changed the cup profile to anything that would convince me to permanently make the switch for now. I still need to check out the Munchow course once I can find some time.
