farmroast wrote:here are the finals profiles and winners announced today. ....

I had a sneaking suspicion another 8min roast would win this year. What unfortunately doesn't show is that the ROR is in fact way off the charts high for the first 4 minutes. The nearly flat down-sloping curve for the final four minutes suggests relative accuracy there, however the TC's are obviously too slow to show it, but I'm certain the ROR bottoms out after the crack.

farmroast wrote:here are the finals profiles and winners announced today. Click on the "download profile" for more data. Can clearly see where contamination effects the BT readings at points

Can you elaborate on that a little?

Also, I understand poor TC placement showing small variations but it doesn't account for the huge differences in those practice profiles.

And, whoa, 8 minute roast. I have already gone from 12 min roasts down to 10:30 roasts due to discussions here, time to start experimenting again.

endlesscycles wrote:Have you seen where Giesen puts their TC? It's way up high next to the trier where it's reading all sorts of things other than BT. Late turning points (more than a minute) and low 1C numbers (below 200C) are clear evidence of poor placement. Roasters who take temp seriously drill and tap as stock TC placements are rarely ideal.

Most if not all commercial roasters have turning points over a minute, usually a minute and a half minimum.

and 200°C is 392°F. I've had 1C hit well below that on almost every coffee I've seen both on my roasters and most others as well that are larger commercial roasters, so both of your counter arguments are invalid. Neither of your two points above are proof of poor placement at all, at least in the world of traditional drum roasting.

But I will agree to your last point, nearly all roasters place their own probes and drill their own holes where they want them, but do you think Giesen is going to let a hand full of people do that to their roasters they donated for use during the contest?

My arguments aren't invalid, your logic is. Obviously most roasters aren't using good thermometry. If they were, their response times would be fast and their 1C temps precise.

But thermometry (placement, latency, whatever) isn't the only factor in turnaround time, eh?

100% placement and latency. Ideally, you witness ET followed immediately by BT at charge. However, most TC's have some mass to cool down during which time BT is rising fast. Roughly the point where they meet is TP. Poor placement includes ET readings during the TC mass cooldown.

20C coffee should take the heat off a 200C 1/4" probe in under 45 seconds.

The top three have short roasting time between 8 to 10 and with a relatively constant but slightly declining ROR.

endlesscycles wrote:
20C coffee should take the heat off a 200C 1/4" probe in under 45 seconds.

Ok, I'm following you now. I have a huge headache at the moment (recovering from a nasty infected cat bite from Monday).

I'll assume that is independent of bean mass and charge temp?

Well anyway; congratulations to Jacky Lai!
He's roasting on a Kapok 5.0 and Kapok 1.0 and has two cafe's in Taiwan.
http://www.kapokcoffee.com/index.php?page=about

endlesscycles wrote:My arguments aren't invalid, your logic is. Obviously most roasters aren't using good thermometry. If they were, their response times would be fast and their 1C temps precise.

We're just going to disagree then. I've already gone over this with excellent roasters like Blue Bottle and the countless others, Verve, etc who all have the EXACT same thing to say about the topic. You stand alone on your own island of belief about turning point times. The rest of them sit somewhere around 1-2 minutes, and they all feel it's a very valid and important factor, that isn't some abstract issue relating to probe mass.

The only part of a probe that matters is the very tip, and that tip will be the same temperature as it's environment. If you dump a bunch of room temperature beans onto the damn thing, it's reading the coolness of those beans until they too start heating up, simple as that.

Most roasters aren't using good thermometry? Ha.