Being the guy who created the owners manual and created all the repair procedures you find on the Hottop website (including the website) I knew the probe was at least part of the problem. Pull that out. It's doing you no good. Somewhere out there (maybe as part of the old HTC+TC4C [?] instructions) I wrote, you will find some info on adding thermocouples to a Hottop. The only viable way is either through the rear wall, or, if you are not that brave, on my website you can find the details on how to add one through the bean loading chute. Also spend a few hours going through the Mill City Roasters School online.

I personally think you're going into first crack too hot. With the small charges you're using you should be be able to use a lot less heat. The first roast the last minute of temperature data you collected shows you were at 35f a minute. The second roast was better but still a little fast at 16f minute.

Thanks for chiming in again, Randy. Installing a proper thermocouple has been on my todo list since I got the machine. This one is just what I have for the time being. In the meantime, I'm curious to hear how you respond to a post that was made just before yours. Here it is:

"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."

This is my rationale, exactly. The temperature reading has been pretty consistent with each of my roasts. I hit first crack in a range between 390 - 405 BT, which I believe to be consistent with theory on when 1st is supposed to happen (correct me if I am wrong). I can see that the probe sits in the middle of the bean mass, which indicates to me that I am reading the temp of that area. Color and smell have also correlate well with the temperatures that I read via this BT probe. However, even if my temperature data differs from most Hottop users, and even if it is less accurate, wouldn't the consistency of readings that it provides shed light on the roast progression and profile?

RobertL wrote:I personally think you're going into first crack too hot. With the small charges you're using you should be be able to use a lot less heat. The first roast the last minute of temperature data you collected shows you were at 35f a minute. The second roast was better but still a little fast at 16f minute.

I plan on playing around with this a bit more today. I ended up blasting heat throughout the roast in an attempt to get the overall roast time down. A 380 charge temp with high heat throughout the roast period seems to be the only way to get to first by 7:45 - 8:45. Obviously, this has not produced a good-drinking cup of coffee, so it's back to the drawing board.

Vbrock9089 wrote: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.

Yes thats essentially what I meant, I'd guess that a good option is to peak ROR or ET towards the middle of yellow and then start to decrease slowly (ET and ROR) to allow BT catch up. I am assuming a lot as to the bean, processing, end goal etc. but hope this helps in terms of thinking of how to roast, rather than an exact recipe to follow. Whether or not the advice I gave turns out to be the right profile type or not for your particular coffee.

From what I have seen, deciding charge temp is usually somewhere around 10-20*F below the end temp. I have heard more than enough talk of roasters who end roasts at specific temps and use that as guidlenes for similar orgin and processed beans. I would say from back 2 to 3 you moved too much, but Dave in the Mill City videos said if you dont know what to do make largish changes. I would guess an charge temp of 380F if you are finishing at 400F, as a start.

Probe placement and type matters if you are tying to compare and replicate other roasters data if you do not have a strong understanding of your own temp numbers and ranges, so fixing your probe as per RandyG. said is kind a must.

The crashing i said for the same reason as RobertL said you are coming in too fast. 16*F/min is ok in my experience but the differential temp gradient between my drum wall (in an air roaster) and yours in a drum will be larger, so you may need to go even slower. Perhaps in the 6-12*F/min range during the finishing development stage.

Thanks for the reply and clarification, crunchybean. It provides good insight into roasting theory, which is exactly what I am trying to soak up right now. I'll be roasting some coffee in a few hours. I have a good bit of coffee, so I'll be doing several test batches to continue dialing in technique. I'll put this advice to practice and let you know what comes of it.

Vbrock9089 wrote:"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."

I was able to dig through and find some roasts. These are the two newest I have available. KN-8828B-2K+ (dual factory thermocouples) read on Artisan's Roaster Scope.

From early 2017:
charge at the signal beep (165F.)
Charge - 165F
TP - 115 at 1:20
DE - 296 8:44
1st begin - 363 12:29
1st end - 383 13:32
Manual drop at 398 14:11 (first few clicks of second)

From late 2016:
Charge - 250F
TP - 161 at 1:11
DE - 307 7:00
1st begin - 373 10:33
1st end - 388 11:39
Manual drop at 401 13:21 (maybe beginning of active 2nd)

This is super helpful. Thanks Randy!

Randy G. wrote:Being the guy who created the owners manual and created all the repair procedures you find on the Hottop website (including the website) I knew the probe was at least part of the problem. Pull that out. It's doing you no good. Somewhere out there (maybe as part of the old HTC+TC4C [?] instructions) I wrote, you will find some info on adding thermocouples to a Hottop. The only viable way is either through the rear wall, or, if you are not that brave, on my website you can find the details on how to add one through the bean loading chute. Also spend a few hours going through the Mill City Roasters School online.

Thanks VERY much for the details on how to add a temperature probe to a HotTop! PDF templates too!

Mark