Not sure how to fix it so here is the second graph.

No worries. But it's still the same profile in all three now.

For me and my roaster, avoiding the flick begins with minimizing the first crack RoR drop. Because if you crash too hard in FC, you almost have to flick to get to a drinkable drop temp. Some folks up the gas slightly into FC. While this does help minimize the FC crash, for me personally I find that my beans crack a bit too hard when I do this, expanding too much, bubbling, and blowing apart.

Recently I switched my style from a bump in gas at FC, to a slight increase in my "after dry" gas adjustment with a corresponding increase in fan speed. The result: my ramp curve stays the same, but I go through first crack without needing to bump up the gas and without my rate of rise crashing too hard. I suspect this result is because I have a hotter drum coming into FC.

I still get a decrease in the RoR during FC with my new style, but it comes later and at a high enough temp that I can just coast to drop.

Results in the cup have been awesome, and the beans themselves look better, too--more even, not bubbled or blown apart.

It's good to hear you guys are getting the hang of it! Congratulations.

Soliloquy wrote:Recently I switched my style from a bump in gas at FC, to a slight increase in my "after dry" gas adjustment with a corresponding increase in fan speed. The result: my ramp curve stays the same, but I go through first crack without needing to bump up the gas and without my rate of rise crashing too hard. I suspect this result is because I have a hotter drum coming into FC.

Cody, will have to try this out but how does this avoid the Pre first crack heat rise that the beans often generate? Does the heat not register due to the hotter drum?

Thanks for the tip - interesting.

Steve

[creative nickname] wrote:Scott stopped by a while back to discuss some of this with us; you can find the exchange here:

Development time as a ratio of roast time by Scott Rao

In that thread I posted about one blind comparison I did, where a SS-FF, flat-line (but not flicked) profile beat out a Rao-rules profile in a blind cupping. Soon afterwards I did another similar experiment using that coffee, with similar results (at least at city roast levels):

Roast and Learn Together - August 2014

But since then I've mostly become a convert, at least when using a traditional drum roaster. In the March-April R&L thread, Marshall encouraged us to couple Rao's "commandments" with a restriction to never increase heat input during a roast. (I had typically bumped heat up as a way to draw out drying and then have a fast ramp, for all my prior experiments.) When I tried doing Rao-style profiles in this manner, they consistently beat out all my other efforts, including the SS-FF, flat-line approaches that I had liked best in prior trials:

Roast and Learn Together - March/April 2015

So now I tend to treat his recommendations as much more valuable. But none of this has included an attempt to isolate just the "flick." I am always game for some blind testing of roasting theories, so I'll give that a shot at the next available opportunity, and post about the results.

Thats awesome that you have played around and decided on a roasting style that works for you. And Im definitely not saying people should be roasting a certain way(i hate when people think there is only one way to do things in coffee). But i know even if people had conflicting experiences with declining rate of rise, or the flick. That they would be hesitant to say so, because it doesn't follow the gospel of Rao. So I feel compelled to offering a differing opinion. I still wonder if the flick/declining rate of rise thing is batch size/profile style/water/thermocouple dependent. Because its obviously works for some folks, and not for others. I know for certain, the larger the batch of coffee the harder it is to transfer the burners energy to the seeds. So as you scale up batch size, the seeds are less efficiently roasted. This is obvious when i take a profile from my smaller roaster to my bigger roaster.

Hi.

Infrared radiation roasts different than conduction and both coexist in a drum roaster. I think infrared penetrates deeper the bean but without causing high heat defects. My guess is that these general profile rules depend on interrelated variables/conditions like for example batch size, which could change radiation/conduction ratio. For example, the best profile outcome for a batch size may be different for another.

Cheers

So, I did my first experiment with this today. I'll post again if my conclusions change, but here is what I've got so far.

I did two profiles of the Kirinyaga Karimikui AA, which I tried to make as nearly identical as possible, except that one was flicked and the other was not.





Both of these were 300g batches, charged at 375, with constant air and heat until FC-start. The non-flicked profile ran 3:20/3:20/2:20, and was dropped at 415F, while the flicked profile ran a tiny bit shorter before I dropped it at an identical temperature. The goal here was to isolate the "flick" as much as possible from other variables that impact taste, such as total roast time, ramp:dev ratio, or finish temperature.

To see the difference more clearly, here are zoomed in versions of the two graphs. The non-flicked roast finishes with an ROR in the 3F/min range, while the flicked roast sped up so that it was closer to 5F/min.





My wife and I tried a triangle cupping this afternoon, after the roasted beans had a few hours to rest, and the differences between them were subtle enough that on my first try I misidentified the flicked cup. Once I knew which cup was which, I spent some time studying them side-by-side until I felt like I could taste a slightly enhanced drying sensation in the aftertaste of the flicked cup compared with the non-flicked ones. (I suspect I missed it the first time because I was switching too quickly between cups, not allowing long enough for this difference in the finish to emerge.) Armed with the new knowledge, I tried three more blinded triangle cuppings and was able to pick the flicked cup two out of three times. So I am starting to think that the difference is subtle but real (although I cannot strictly rule out the possibility that the differences are solely the result of 5 more seconds development time in the flicked cup).

Now, I'll be the first to admit that this very slight difference in astringency is a far cry from the "charred" tastes that Rao describes in his post. But keep in mind that he was describing what happens when roasters let ROR flick up and stay up for a while, and then reduce overall development time to keep from finishing too hot. My experiment revealed differences that were more subtle because it is just really hard to keep all other variables equal between a flicked and a non-flicked roast! But it does give me some confidence in thinking that it is worthwhile to try to keep my roasts from accelerating once first crack is dying down, even for a roast that will otherwise hit all my targets.

Finally, I also think it is worth saying that one way to view these results would be that if you get your other targets right, a slight flick towards the end will make a difference so subtle that it probably isn't worth worrying about that much. At best, this might mean a quarter-point to a half-point difference on an overall cup score, which is hardly the end of the world either way. Before I knew what to look for, I couldn't even tell the difference.

Will be studying your comments and charts this evening/tomorrow. I have been able to get a bit of a handle on them thru your posts. Thanks. Dave

[creative nickname] wrote:Once I knew which cup was which, I spent some time studying them side-by-side until I felt like I could taste a slightly enhanced drying sensation in the aftertaste of the flicked cup compared with the non-flicked ones. (I suspect I missed it the first time because I was switching too quickly between cups, not allowing long enough for this difference in the finish to emerge.)

I commend the the attempt to empirically test these ideas, but an alternative explanation for the above would be that once the cups were unblinded bias led you to find what you were looking for. This is why randomization and blinding are so important in experimentation, even if it is espresso. Plus, it would be good to do more than a single trial.