Well said. The only reason we even consider it, is because someone wrote a book about how important it is. The shape of the bean curve and thus the ROR is so dependent on machine design (thermal insulation, bean probe location/thickness, etc). If I base everything on a "pretty" shaped ROR curve on my 6kg machine, this would have me hitting FC around 8min and dropping coffees too early. Or, because my machine is so well insulated, I would need to have a lower turning point to have a steeper curve during the drying phase and it would require lowering my preheat quite a bit and then firing harder then I would normally. In reality, if I hit FC at 8 min, the coffee will taste good for 2-5 days and then flavor drops off fast, whereas a FC around 9:15-9:45 seems to be the sweet spot for my machine and results in a full-flavored cup that holds on to flavor for over a month.
Great that the RoR considerations are continuing to be understood. The initial RoR development was on an experimental hybrid design roaster that specifically had almost no metal mass. Mechanical agitation and low air flow, electric heat.
Hello. You said that shorter development time will give more fruity acidity and longer development time less fruity but more chocolaty. Do you think that the time to first crack will also influence acidity in the same way, I mean shorter time to first crack more acidity and later first crack less punchy acidity? Regards from Poland :)
Until you can find a better way to systematically judge smell and color of coffee development than time IE to fast or slow development then time in roast cycle color and smell will always be the judge of optimal development. I am okay with you not liking time and rate of rise and the judge of development, however you have not suggested an alternative method of tracking the development life cycle in roasting coffee either. I would also argue slowing down the rate of rise right before the first crack starts a gentle soft first crack as energy exports from the bean in every crack. This slows down the malliard reaction the sugar chain development and stretching it out as long as possible to the beginning of second crack. I opt to reduce the gas right before first crack until it is finished then gently raise the gas gently every minute softly to the beginning of audible second crack and finish of the roast. This is optimal all though you could argue this is objective taste preference, and I would say you are right. Basically reducing the gas right before the first crack exothermic state keeps the energy on the same path in general. Not reducing it before exothermic adds energy to the equation instead of keeping it consistant. Not adding heat back in after first crack will stall energy and the roast moving forward into the second exothermic state second crack and end of roast for me. Stalled state or raise of rise causes fermented yeast type bread flavors. Push a roast to fast through the development phases causes black tipping or scorching on the tops and bottoms of the beans. Also to agrissive development causing fisures blow holes in the beans structure in an aggressive cracking phase. TAKEAWAY = if you don't want to use time and temperature IE rate of rise, you must suggest an alternative to measuring the development stages in roasting consistantantly. You have not done that.
Hi Jason. Thank you for your thoughtfull answer. I'm not saying not to use time. I'm suggesting to use time and temperature separately and only when it is relevant (what I explore in the beginning of the blogpost under the title "Where is the concept of Rate of Rise useful in coffee roasting?") to look at the Rate of Rise. If you want a more thorough and systematic approach to our understanding of coffee roasting I will refer you to this scientific article that is available for free here: www.mdpi.com/2306-5710/6/2/29# and after reading that this one could be relevant to understand how we see time, temperature and flavour related and which concepts to use to describe it: www.mdpi.com/2306-5710/6/4/70 Hope it makes sense :-)
Well said. The only reason we even consider it, is because someone wrote a book about how important it is. The shape of the bean curve and thus the ROR is so dependent on machine design (thermal insulation, bean probe location/thickness, etc). If I base everything on a "pretty" shaped ROR curve on my 6kg machine, this would have me hitting FC around 8min and dropping coffees too early. Or, because my machine is so well insulated, I would need to have a lower turning point to have a steeper curve during the drying phase and it would require lowering my preheat quite a bit and then firing harder then I would normally. In reality, if I hit FC at 8 min, the coffee will taste good for 2-5 days and then flavor drops off fast, whereas a FC around 9:15-9:45 seems to be the sweet spot for my machine and results in a full-flavored cup that holds on to flavor for over a month.
Hi Alex. It seems many educators use this (and therefor students) so that's why I have been so frustrated not being able to make sense of it myself.
Great that the RoR considerations are continuing to be understood. The initial RoR development was on an experimental hybrid design roaster that specifically had almost no metal mass. Mechanical agitation and low air flow, electric heat.
Hello. You said that shorter development time will give more fruity acidity and longer development time less fruity but more chocolaty. Do you think that the time to first crack will also influence acidity in the same way, I mean shorter time to first crack more acidity and later first crack less punchy acidity? Regards from Poland :)
We're all dancing around the name of Scott Rao.ROR is his baby,
Until you can find a better way to systematically judge smell and color of coffee development than time IE to fast or slow development then time in roast cycle color and smell will always be the judge of optimal development.
I am okay with you not liking time and rate of rise and the judge of development, however you have not suggested an alternative method of tracking the development life cycle in roasting coffee either.
I would also argue slowing down the rate of rise right before the first crack starts a gentle soft first crack as energy exports from the bean in every crack.
This slows down the malliard reaction the sugar chain development and stretching it out as long as possible to the beginning of second crack.
I opt to reduce the gas right before first crack until it is finished then gently raise the gas gently every minute softly to the beginning of audible second crack and finish of the roast.
This is optimal all though you could argue this is objective taste preference, and I would say you are right.
Basically reducing the gas right before the first crack exothermic state keeps the energy on the same path in general.
Not reducing it before exothermic adds energy to the equation instead of keeping it consistant.
Not adding heat back in after first crack will stall energy and the roast moving forward into the second exothermic state second crack and end of roast for me.
Stalled state or raise of rise causes fermented yeast type bread flavors.
Push a roast to fast through the development phases causes black tipping or scorching on the tops and bottoms of the beans.
Also to agrissive development causing fisures blow holes in the beans structure in an aggressive cracking phase.
TAKEAWAY = if you don't want to use time and temperature IE rate of rise, you must suggest an alternative to measuring the development stages in roasting consistantantly.
You have not done that.
Hi Jason. Thank you for your thoughtfull answer. I'm not saying not to use time. I'm suggesting to use time and temperature separately and only when it is relevant (what I explore in the beginning of the blogpost under the title "Where is the concept of Rate of Rise useful in coffee roasting?") to look at the Rate of Rise.
If you want a more thorough and systematic approach to our understanding of coffee roasting I will refer you to this scientific article that is available for free here: www.mdpi.com/2306-5710/6/2/29# and after reading that this one could be relevant to understand how we see time, temperature and flavour related and which concepts to use to describe it:
www.mdpi.com/2306-5710/6/4/70
Hope it makes sense :-)