I did a search on drop temps and didn't find a lot specifically related to it.

Do most people consider the "drop temp" just a by product of the development of the roast? or is it a definite target you are shooting for.
Again this has to do with the Declining ROR discussion.
Temps posted in the discussion should include a 1C temp and a 2C temp (your average) since everyone's probes read a bit different.

I hit 1c at 365 F and usually 2nd at around 410 F(or close to it .. don't go there very often) and usually try to drop in a 398-400 temp with a good development time. This usually puts me in a FC roast neighborhood ... if I have a really slow ROR and can only muster a 385 without hitting the gas then it really doesn't feel like it has been developed well ... despite an adequate development time.

Would be interested in hearing from others on this ...

Steve

You'll really need to better measurements for it to mean much. At that point, it'll mean exactly the average bean surface temperature...which in and of itself still doesn't mean much.

Elaborating further, full and complete development can happen at any temperature above 1C, which should happen when reading 392F/200C +/- 9F/5C. If the final temperature is significantly higher than 1C temp, then it will taste dark.

Now, seeing that average bean surface temperature is INCREASING from 1C to drop lets you know that more than sufficient thermal energy is being applied to keep the crack going. Seeing that surface temperature is increasing quickly during that time indicates that too much energy is being applied, and you'll end up with a higher drop temp and a darker coffee.

(Marshall is ahead of the curve on roasting theory )

Definite temp. target!

Another related question: post 1st crack development time vs drop temp? Which would take preference?
I would give preference to drop temp. every time; even if it risked ruining the roast.

Lets' just say for example your running two identical normal roasts with the same charge temps., profile,
and 1st crack temps. Now you have the option of choosing the post 1st crack development time and temp.
Do you target the final drop temp? My answer would be yes.

Steve, I think probe placement and readings are going to vary too widely for "takeaway" conclusions. What would be more important is your readings relative to what you want to do with the bean in tweaking it from prior roasts.

You get 1C at 365. Mine usually come at 390-394, depending on bean. Just looked at an exercise on SM's and he is stating 401. Trying to remember what Rao said. There is too much inconsistency in set-ups to make much sense of that or base roasting decisions on that.

Just an opinion.

PS, see you in Seattle.

Dave

I typically target a certain among of temperature increase past first crack as well as a particular window of decelopment time. For a pretty standard 9-10 minute roast of a wet-processed coffee intended mainly for brewing, FC-start-temp plus 18-22 F, stopping around 2:00 to 2:15 after FC-start, would be typical targets.

I also more or less target a temp. But development time definitely has a little sway on the decision to drop or not.

[creative nickname] wrote:...coffee intended mainly for brewing, FC-start-temp plus 18-22 F, stopping around 2:00 to 2:15 after FC-start, would be typical targets.

Bingo. Same here and tweak after that initial roast.

hankua wrote:Another related question: post 1st crack development time vs drop temp? Which would take preference?
I would give preference to drop temp. every time; even if it risked ruining the roast.

I would agree with you on this. I have found my roasts missing a bit of the character I am looking for if I "no matter what" drop at the maximum 25% of development time per Rao causing me to drop at a lower than planed temp (I know it is a guide not a rule). It tastes a bit better if I can get up to a drop temp I'm looking for and go longer in development past the 20-25 % development guideline.

That said ... nailing both (development and drop temp) is best! This really comes up when trying to salvage a roast that goes south.

I had a great roast on a Klatch Yirgacheffe Gedeo that I had ... interesting in that it didn't seem to go through much of an endothermic flash at 1c. Got some fantastic berry flavors. When I tried the same roast on the HB Yirgacheffe Gedeo , the pronounced endothermic flash temp drop took me by surprise, which left me with no headroom in the ROR to hit my drop temp without stretching the roast a lot. It happened to me twice ... (thought it was just because it was my first roast and maybe the roaster wasn't warm enough - it was) You could find the berry there but it was really lacking. Never seemed to nail that coffee as well as the Klatch. So on one I stretched it out to hit a 398 drop temp and the other I dropped it at 25% development time at 385 .... the drop at the higher temp was better.

Steve

Once you identify baked flavors, they become so clear and obvious that every coffee (of sufficient development, being defined by exhibiting enough solubility to get 20% extraction from "normal" espresso parameters) has baked notes to varying degrees. Trying to "correct" a roast that doesn't seem to be getting to "target temp" soon enough will increase the prevalence of baked flavors.

By the quotation marks I am indicating personal issues with the concepts of normal espresso, correcting a roast, and aiming for target temps.

I wonder if the shape of a profile might be more indicative of its success than the actual temperatures (within limits of course). If the curve is taken into consideration rather than absolute temperatures it might make the temperatures that the OP mentioned for FC less critical.