https://www.mdpi.com/2306-5710/6/4/70/h ... i8fRCpxn-Y
Cheers Mark
Interesting study regarding roast development times
Re: Interesting study regarding roast development times
Yes Mark really very interesting!
Have you any thoughts how to change a profile to get the "fast" version (or even the "medium" version). In this article or work they don't mention DTR at all. The KL profiles are very much built around this. Even if they tried to get the same colorometric value on the roasts DTR differs a lot. The colorimetric value only says something about the roast degree up to 80% then there are other factors the next 20%. I guess the fast version has a higher end temp but a low DTR. The "baked" version has a lower end temperature but a high DTR. The fast version could be uneven inside out and the baked is probably evenly roasted but baked because of the extreme developing time. It has probably stalled. The four roasts has the same color but different roast levels. I think this study raises more questions than answers. I also wonder if it's a fair comparison? They don't show the ROR from the different roasts. But anyway interesting what happens chemically when you bake a coffee!
Have you any thoughts how to change a profile to get the "fast" version (or even the "medium" version). In this article or work they don't mention DTR at all. The KL profiles are very much built around this. Even if they tried to get the same colorometric value on the roasts DTR differs a lot. The colorimetric value only says something about the roast degree up to 80% then there are other factors the next 20%. I guess the fast version has a higher end temp but a low DTR. The "baked" version has a lower end temperature but a high DTR. The fast version could be uneven inside out and the baked is probably evenly roasted but baked because of the extreme developing time. It has probably stalled. The four roasts has the same color but different roast levels. I think this study raises more questions than answers. I also wonder if it's a fair comparison? They don't show the ROR from the different roasts. But anyway interesting what happens chemically when you bake a coffee!
Re: Interesting study regarding roast development times
Hi,
Regarding the article above what happens with a roast tastewise and chemically at different developing times. In the study it looks like they used the same ground profile but made changes during the developing phase. I have a profile I've used but sometimes the roast even if it's light can give a bitter aftertaste maybe a tendency to be baked even if the DTR isn't more than about 20%.
I made a change to the profile by making it a bit steeper. Not to overload the roaster I also lowered the fan speed at the end of the roast. I made two roasts with the same bean. I roasted to the same DTR about 20%. The modified profile gave a 1/2 minute faster roast. The end temperature was similar maybe a little higher with the unmodified profile. Because of the faster roast the developing time was 9 sec shorter with the modified profile. This roast became about 10% lighter colorimetric. In my case DTR was a more constant factor. In the study a colorimetric value was the constant.
Well taste with a filter brew? The modified profile tasted sweeter and less bitter. It was very nice even if I tasted it a bit early the day after the roast. The unmodified was more bitter maybe a tendency to be "baked" even if the ROR curves were rather similar and looked ok. I will experiment with this further.
The study focused only on developing times and measured the roasts colorometrically to the same Agtron number. I've searched the article for "DTR" but I can't find it. Maybe they don't recognize DTR as an important factor?
Regarding the article above what happens with a roast tastewise and chemically at different developing times. In the study it looks like they used the same ground profile but made changes during the developing phase. I have a profile I've used but sometimes the roast even if it's light can give a bitter aftertaste maybe a tendency to be baked even if the DTR isn't more than about 20%.
I made a change to the profile by making it a bit steeper. Not to overload the roaster I also lowered the fan speed at the end of the roast. I made two roasts with the same bean. I roasted to the same DTR about 20%. The modified profile gave a 1/2 minute faster roast. The end temperature was similar maybe a little higher with the unmodified profile. Because of the faster roast the developing time was 9 sec shorter with the modified profile. This roast became about 10% lighter colorimetric. In my case DTR was a more constant factor. In the study a colorimetric value was the constant.
Well taste with a filter brew? The modified profile tasted sweeter and less bitter. It was very nice even if I tasted it a bit early the day after the roast. The unmodified was more bitter maybe a tendency to be "baked" even if the ROR curves were rather similar and looked ok. I will experiment with this further.
The study focused only on developing times and measured the roasts colorometrically to the same Agtron number. I've searched the article for "DTR" but I can't find it. Maybe they don't recognize DTR as an important factor?
Re: Interesting study regarding roast development times
I found it interesting that the grind method was not accounted for nor described in such a "controlled" experiment. No mention of the grind size, burr size, burr type nor burr geometry was mentioned. From my research this can have a significant impact on "body". They concluded unilaterally that development time did not have affect on body, when they did not account for the grind variables at all.
Re: Interesting study regarding roast development times
Hitennr wrote: ↑Thu 07 Jul, 2022 6:01 am I found it interesting that the grind method was not accounted for nor described in such a "controlled" experiment. No mention of the grind size, burr size, burr type nor burr geometry was mentioned. From my research this can have a significant impact on "body". They concluded unilaterally that development time did not have affect on body, when they did not account for the grind variables at all.
Wouldn’t the grind be treated as constant for their research. Otherwise you’d have to consider every other variable relating to taste and flavour. It would be a minefield and outside their scope. Modulating the development time is what they are concentrating on. That’s my takeaway from the article, from what I understand.
Cheers
G