Going Light on Hottop Roaster

[jsab]

I've recently gotten into roasting and have purchased a Hottop P model. I have been doing 1-2 roasts a day for about 3 weeks now and am having trouble reaching a city or city+ roast. Even though the times seem to be in the relative area, the beans come out looking very dark.

I'm installing an omega thermocouple this week (via Randy Glass and Espresso! My Espresso!) and am hoping to get more accurate results.

Still, when I compare my "city" roast to local roasters, they have much lighter (and even) beans. I have even used Hottop's recommended city roast settings, still come out very dark. Any Hottop roasters who can help? What segments do you use for your lightest roasts...?

 

[Music_Geek]

You will learn a lot from the thermocouples.

My guess is that your charge temperature is too high, if you're particularly uneven. Then the next question would be a matter of how fast are you reaching particular landmarks in your roast?

So the first thing you're tracking, is the charge temp (how hot is the roaster when you add beans) and the charge time.
Then the next thing is "dry end." This is when you see the beans go from bright green to "yellow, orange and brown" and the smell gets distinctly like hot wet hay... like a sweet grassy smell, but nothing like "burnt toast" or bread. Mark this time down.
Then first crack. Mark the time you hear the first GROUP of cracks down... much like popcorn, there are usually a couple of jokers in there that crack early... you don't call it first crack until you hear a small group of them cracking. The way you play with heat and air flow during this part of the process will dictate how vigorous of a first crack you get.
Then mark the time for the END of first crack... when you stop hearing cracks.
Finally, second crack's start. As you should know by now, second crack is more of a subtle sound.

If you can give us the times for these events (if you don't reach second crack, that's fine... you may not want to, for a city roast) we can probably help tell you what variables to play with.

It doesn't really seem to matter how quickly you get to dry end.
It seems to matter GREATLY how long you take to get from dry end to first crack.
It is of MASSSSSSIVE importance, how long it takes you to go from first crack to second crack.

I have found zero agreement among roasters about what technically constitutes City or City+ roasts. Some say "drop during first crack for City roast." Some say "drop before second crack for City roast." Some say "up to the first few seconds of second crack for City roast." I think technically, these all might be right, depending on the roast method/speed and the bean type. But if you're getting very dark beans, I am really curious how long it's taking.

 

[jsab]

My thoughts were that it was taking too long to reach first crack, so I should set a higher charge temp and a more vigorous drying phase to reach it. So, I've been playing around with higher charge temps. Here are some examples of my roasts (temperatures from the Hottop display):

Charge:264 - Yellow:6:30 - Brown:8:00 - FC:9:30 - Eject:11:07 at 399F (colombia inza)
Charge:315 - Yellow:5:40 - Brown:6:20 - FC:9:05 - Eject:10:50 at 396F (ethiopian yirg dumerso)
Charge:264 - Yellow:5:30 - Brown:7:30 - FC:9:09 - Eject:11:30 at 410F (colombia inza)
Charge:264 - Yellow:5:30 - Brown:7:30 - FC:9:40 - Eject:11:38 at 399F (colombia inza)

I have been considering a city roast to be dropped at the last stages, or right after, FC. City+ is left for 15-20 seconds after FC. Thanks for the insight hope this helps

 

[Music_Geek]

These times are all totally reasonable. You shouldn't have a particularly dark roast at those temperatures, either. Many beans, you're just getting INTO FC at 380-390. You may have issues with the RoR during the time from dry end to FC, and in development phase. How are things tasting?

For what it's worth, if you compare against fluid bed results, you often find a lighter color at a similar roast level.