hi-

from the info i gathered, i'm trying to keep these roasting 'rules' in mind:

1) 4 min from start of 1C to end of roast is ideal
2) to avoid stalling the roast to maintain 50F between BT and ET

hard for me to achieve both on my hottop -- can do one or the other. if i lower power a bit before 1C, i'll be able to stretch it, but also the 1C cracks won't be as active... the gap between BT and ET might drop to 20 - 30.

if i reach 1C (389F BT usually), and ET is 440, it'll power though 1C, but also it'll reach 2C in less than 3 min, even though i'm able to flatten the ET to 450F.

any tips? chart below shows charging 150g (SM Workshop#10) at a high ET, it seems lower than this, it's harder to keep that 50F gap between BT & ET. I ejected them at 9:40 right as i heard first signs of 2C, which i did not want to reach (aiming for FC).

Don't worry about your ET until you can get the profile you want based on BT only. If you don't nail your intentions, then take it as a lesson and taste the results then try again. Don't get stuck in this whole "rules of roasting" head space, as they don't entirely exist.

9:40 to 2nd crack may be a bit fast.

Just a suggestion. Concentrate on one temperature only, be it ET or BT, and correlate the temperature with different roasting stages.

The shape of the coffee bean is quite a complex structure that still cannot be described mathematically, not to mention the volume also changes during roasting. Imagine even for a single bean, the center and surface will have different temperatures. Just for these two reasons, "BT" is really not bean temperature.

HotTop is unique in that it has conduction, convection, and due to perforated drum and electric heating element, radiant heat. Even so, utilize the HotTop fan more frequently, as convection is a predominate form of heat transfer. By increasing the fan and lower the heating element about one minute prior to expected first crack, the duration from 1st crack to 2nd crack can be readily adjusted.

If you don't mind, please post your other setting, like fan speed and power settings at different times.

in this case i had full power, no fan... until smoke started, maybe ~360F 'BT', then fan to 1 until end of roast.

if i reduced power 1 min before 1C start -- it would be much less active during first crack.

so should i increase fan even more and it'll help?

putting temps aside, are these guidelines to shoot for:

1) have at least 3 min from start of 1C to end of roast... but ideally 4min for espresso roasts.
2) have a healthy sounding 1C, with lots of pops
?

I think you will find it easier to get a decent "intercrack interval" if you charge the HT with more than 150g. I haven't used my HT in quite some time, however I would suggest that you try a bean load of 200 or even 225g.

4-5 minutes is a good range to shoot for from the onset of 1C to the end of the roast, as long as you are not doing a very light "cupping roast." For sure, you want "lots of pops" in the 1C, however you want these "pops" to be spread out, not all at once. When you do succeed in drawing out the "intercrack interval," you will notice that most of the audible pops of 1C occur in the first ~2.5 minutes or so after onset 1C. You then get a period during which audible popping is more or less absent, before 2nd crack begins, assuming you want to go that far into the roast.

ken

benm5678 wrote:putting temps aside, are these guidelines to shoot for:

1) have at least 3 min from start of 1C to end of roast... but ideally 4min for espresso roasts.

Yes, that's a good general rule of thumb.

benm5678 wrote:2) have a healthy sounding 1C, with lots of pops

No. A vigorous first crack might be entertaining, but its not something you should aim for on every roast. Some beans might call for a faster temperature ramp, which would cause a more aggressive first crack. Others call for a slower ramp, and thus a feebler first crack. There are also other factors, like bean freshness/moisture content, bean uniformity (size and ripeness), and perhaps others that all impact how aggressive the first crack would sound. So its not something you should strive for on every roast.

Ken Fox wrote:I haven't used my HT in quite some time, however I would suggest that you try a bean load of 200 or even 225g.

More beans would increase the volume of "pops" and help normalize things, but batch sizes of 200g+ in an unmodified Hottop get tricky in my experience. You end up needing such a high ET that you'll start seeing tipping and even charring in lower altitude beans.

I do batch sizes of 7oz/200g with my Hottop which has added drum fins, and is about as big a batch I can do at the moment. I'm starting to play around with running that fan at least at half power throughout the roast to improve things, as chang00 has suggested, but its still a work in progress for me...

I agree with the batch sizes on the Hottop. While the manual talks about 250-260gram roasts, I like many others have found that(depending on who you talk too), between 170-225gram batches produce better results. But, you have to pay attention when trying less and less beans, because you hit a point where the beans don't really tumble around anymore, and end up more or less just sliding around the drum. Me, Im between 170-185gr. Usually 170gr, and I raise the batch for Peaberries/smaller beans.

At 150grams, if you're at 100% heat until 360F, the 9min to second crack sounds about right. You shouldn't even "need" 100% at that batch size.. 60-70% should give you some pretty fast ramps up to 1C. In general, 9mins into the roast would be on the early side, but still acceptable, for when 1C would start. I hit 1C usually around 10-12mins in, depending. But, there is a million exceptions and reasons why thats good and bad.

Currently I have two different "profile approaches" Im playing with, obviously which get tailored to how each bean likes to be treated, but, what really got me going and helped me start to develop my own profiles, essentially started with the profiling tips Randy Glass has on his website. That was my starting point, and I made changes to it to suit my needs/tastes, and went from there. He outlines a general approach to the roast, which gives you a base to work from. That was a huge help for me, maybe it will be for you as well.

The other thing which helps me a great deal, is(using my log), calculating the Deg/Min rise throughout the roast. I do 30sec intervals for my logs, and based on the BT readings from the previous minutes log, I can see the Deg/Min rise in the roast, and how IM affecting it. This allows me to see how much I can slow down the stretch between 1C starting and the end of roast/2C, without worry of either going to fast and hitting 2C, OR, going to slow and stalling the roast. Idk, but maybe that will help you.

thanks a lot for tips! i understand better what to aim for, and really that i just need to keep experimenting more on my equipment (as opposed to searching for some magic formula), but think it's getting there...

this 150g batch had good 1st crack... seems I need that P10, otherwise, i'd get very inactive 1C. I tried bigger batches, but switched to lower to save beans when realized it wasn't necessarily helping. I cut power dramatically to slow down ramp... but raise it again to keep things going... I think here is where i find ET helpful... since i can see a 'warning' sign if it starts evening out, time to crank some more heat -- I wish i could see the ramp speed on the hh506ra for T1/T2.

Fan was never shut off (left on 1). The yellow region got shifted, it was really 8:00 - ~10:00... when dumped at 12:00 no sign yet of 2nd crack

Lower your bean dose. During first crack you get an exothermic reaction, the beans give off heat. In a small roaster with a lot of beans, that exothermic reaction will run ramped and push a lot of extra heat into the mix because you do not have adequate air flow through the dense bean mass in the small roaster. I use smaller bean weights, as first crack starts I will crack the chaff tray open on my HT to allow more air to flow through. Some times I will even take the charging chute cover off to allow more cool air to flow through. As first crack is nearing completion I will close it back up. Very unscientific way of doing it and to much air you will stall the roast and bake your beans but after a few hundred roasts, you get the hang of it. I have the old digital hottop, no programming so I get what the built in profiler gives me and adjust the best I can.