Roasting for espresso, in a HottopB. Lately I've been experimenting with different settings, trying to get a handle on accurately stretching the time between the beginning of first crack and the end of the roast-- aiming for 4:30 from first crack to beginning of second crack. This morning I roasted 8oz of Guatemala Finca La Jolie. As first crack was approaching I lowered the heat a little bit and once it was well under way I dropped the heat to 50% and when first was done I dropped the heat to 30%. Previous experience shows that second crack will come about 3-3:30 after onset of first using this method so I removed the bean chute and rear filter for 20 seconds (with the fan at 50%) once first crack was completely done. At 4:00 I raised the heat back to 100% and dropped the beans at 4:30. No second crack at all.
So would you consider this a stalled roast? Any insight as to what this "stall" will do to the flavor? Thanks!

In case anyone is interested- using that same approach with another 8oz batch of beans (El Salvador Santa Ana Naranjo) I lifted the bean chute and pulled the rear filter for 15 (just a little less than last time) seconds and got exactly 4:30 from the beginning of first crack to the beginning of second crack

I have no problem getting the stretch I want with both the chute cover & filter in place. I use a combination of reduced heat before & during 1C as well as higher fan speeds until I have control of the BT rise. I have replaced the rear filter element with a stainless screen for better air flow.

I tried many many times and just couldn't get the stretch time, even lowering the power to 20% once first crack was under way (and having lowered the power to 80 roughly 45 seconds before first started). With an older or new rear filter I struggled to get more than 3:30.
How much do you lower the power during first crack? Thanks for the feedback, by the way.

Also, what did you use for that stainless screen?
Thanks!

I use these aluminum fan filters: http://www.amazon.com/gp/product/B0009Y...os_product You need to remove a little material from the stock filter holder plastic tabs & then they snap right in.

As far as cutting power I usually drop to P4 or P5 before 1C & go to F4 at the first stray pops of first crack. Once the BT rise slows noticeably I bring the power back up to prevent stalling & taper off the fan. How much of each I use during the stretch depends on the roast level I'm after & whether I'm doing a brew or espresso stretch.

I should add that I use a Variac to maintain a minimum 119v-120v feed showing on my energy meter at all times as I only get 117v at my outlets. This requires 123v on the meter before I turn on the HT.

I appreciate the help and will see if I can successfully duplicate your technique. I ordered a couple of those filters by the way- so thanks for saving me some money

First crack is exothermic, the beans are pumping heat out. I run 150-250 gram loads. Just before first (based on the bean mass temp) I cut the power to 70% and turn the fan on at 50%. Once the first couple cracks of first start I drop the heater to 10 or 20% depending on the load. The larger the bean load the more heat they put out. I also turn the fan up to 75%. First crack runs on its own. Just as I am nearing the end of first I cut the fan to 25% and turn the heat back up to 90% to prevent the roast from stalling. Then I feather down the heat to get the time/temp I want. There are a hundred way to skin a cat, it is just a matter of finding the one that work best for you.

Thanks very much for the info. I'm going to try your suggestions/technique on my next espresso roast and see how it compares to the El Salvador beans I'm enjoying right now.
Are you dropping the heat during the drying phase at all? I have been for the last few dozen roasts and I now I need to try some without and see what that does. There seems to be a lot of differing opinions about this.