Hey all. I'm struggling to get good flavor from the coffee that I'm roasting on my Hottop. I'm certain that it is not the bean, as I drank it in a cafe and it was killer. Specifically, each of my roasts have tasted bready, flat, and flavorless (baked). I'm confused by this though, because my roast times are significantly shorter than average HT roast times.

My flaw may be that I am fighting to get the same roast times that I used to have on a Joper dual-drum sample roaster, roughly 9:30 - 10:30 total roast time. Here are the variables that I tend to keep constant in each roast:

Charge Weight: 175g
Charge Temp: 380 - 400
Development: 1:30 - 2:00

The more important, nitty-gritty can be seen in the images attached to this post. They are the notes that I've taken during my roasts. The best tasting note that I've gotten out of any of these coffees has been a toasted nut and slight char. I'm curious if you all have any advice for me!

What model Hottop, where is the temperature data coming from, and what beans are you using? How old it the main filter, and how dirty are the fan blades? Etc.? Plus, it can be difficult to take a profile from a small gas roaster and transfer it to an electric roaster.

Answers to the previous poster's questions would help get the conversation started.

I've never been able to get a good tasting roast on any bean with the charge temps like you are using. I realize they are very popular, but I suspect our TCs are reading different (see my sig for my model). I read TB at about 345F for 1C for most beans. Yes, I know that is not correct. But my point is that I charge at 220F usually, turn in 55sec at maybe 140F, mark dry at 5:30min and 265F, 1C at maybe 9min something and 345F and drop at 365F at 22% development, maybe 365F. 2C on my TB probe is around 380 as I recall. This is an over generalization of course.

You development is short I suspect because it is a light roast: still quite short. It is also noteworthy that the bean temp from 1C to drop is essentially flat. Some would say that produces a baked flavor; I have no experience in this light a roast/short development nor flat temp development phase.

regards,
Brad
Edit: I charge 226g

Randy G. wrote:What model Hottop, where is the temperature data coming from, and what beans are you using? How old it the main filter, and how dirty are the fan blades? Etc.? Plus, it can be difficult to take a profile from a small gas roaster and transfer it to an electric roaster.

I knew that writing this post in a rush would require some more information later on. Here are those details:

Model: KN-8828-B2
Beans: https://thepantrycs.com/collections/who ... ledon-12oz
Temperature Data: BT via a thermocouple snaked underneath the front glass door
Fan Blades: Deep cleaned the whole machine two weeks ago. It's perfectly clean (minus 15 roasts)
Main Filter: I'm assuming that this is the back filter, not top. I replaced it about 20 roasts ago

Hope this helps diagnose the problem. Happy to share other information if it will be helpful.

First, the blend- I wonder if it is a post-roast blend.

Your thermocouple location is different from any other I have seen done. Assuming that it is an insulated wire K-thermocouple it is likely reading the temp differently from anyone elses so it is difficult to use those temperature to make any real comment.

When I was roasting on Hottops I used Artisan and, being a visual learner, depended a lot on the ROR curves to manage my roasts. Others may be able to comment better on your raw data.

Based on the temperatures, and that you are dropping at 10:00, but at 7:30 you are displaying a temp around 390 to 400 range, I think your temperatures are off. On the B-2K+, BT temperatures 400 and up are into 2nd iirc. Once again, your temperature data seems to contradict what most Hottop users will see I think. I could be wrong. I have no Hottops from which to compare. Based on t=your tasting notes, the temps you are getting could be 20 degrees higher than the actual bean temp. Just guessing.

You are possibly charging to hot. But that is in relation to everything else and is not the problem; its because of your charge temp and your ripping through green (which will give you that nice char taste, mmm mmm). But more importantly you are crashing, hard. Batch #2 and 3 have different charge weight and effect you turnaround point/momentum. The crash could be you not navigating the moisture loss well during the roast, since your millard is longer than your dry/green, maybe try dropping to 80% power and then working back to 100% quickly. And maybe you can introduce more momentum but going from 80 to 100 than just flaming the beans with all 100 from the start.

Soft beans need the heat up front but ive seen they have trouble taking on heat in the beginning and then are more readily to fizzle out/crash out/burn out going from Mexico to Brazil so a Coasta Rican bean should be about right in thr middle. So my guess is to reduce to after you drop your beans and bring it up to full power in 3-4min and hopefully that wont make you pop so hard and crash.

All that being said, it is just the beginning to navigating the whole roast depending on where you want to land.

crunchybean wrote:You are possibly charging to hot. But that is in relation to everything else and is not the problem; its because of your charge temp and your ripping through green (which will give you that nice char taste, mmm mmm). But more importantly you are crashing, hard. Batch #2 and 3 have different charge weight and effect you turnaround point/momentum. The crash could be you not navigating the moisture loss well during the roast, since your millard is longer than your dry/green, maybe try dropping to 80% power and then working back to 100% quickly. And maybe you can introduce more momentum but going from 80 to 100 than just flaming the beans with all 100 from the start.

Much appreciated. I have a few questions in response. When you say that I am crashing hard, are you referencing the very end of the roast? Or are you referring to the slowdown in ROR right after green? Also, what is an appropriate charge temp on the hottop, in your opinion? And lastly, charge with the heat setting at 80% and working up to 100% within a few minutes?

Correct me if I am wrong. It sounds like you recommend charging at a lower temp and heat setting, stretching out my dry time to build momentum, and then get through yellow/maillard quicker.

P.S. I was running low on that coffee and had to charge the last two roasts at 155g. That roast was a bad example, as I have been charging 175g consistently.

Not trying to discount Vbrock's comments, but RandyG has made one heck of a crucial point: your probe for BT is suspect or at the very least an large unknown with suspicious readings. Any conclusions drawn from said probe would be of questionable value.

Perhaps some well thought out BT-probe validation would pay the greatest dividends at this juncture?

respectfully,
Brad

Thanks for chiming in, Brad. The more, the merrier (and better chance of me actually roasting drinkable coffee!)

True, it's not the most legit, but here are my thoughts: See the image attached to this post. The thermocouple end sits right in the bean mass when the drum is rotating. Maybe it's beginners ignorance, but I trust it enough to use the data that it spits out. Curious to hear what you think now that you've seen what it looks like. Also, and maybe more importantly, it provides consistent data on ROR. Even if the temps are not incredibly accurate, the raw data would shed light on my roast progression via an analysis of the ROR. I tried using the ET reading on the control panel, but found it was wildly inconsistent.

Your temperatures aren't in line with other Hottops but other Hottops aren't in line with most roasters. Around 390-400f has always been the temperature first crack is expected to start. I had a Hottop with aftermarket probes that I added through the back wall, I always hit first around 390-400f.