One thing I tried this morning that was interesting: to mimic the effect of greater soluble polysaccharide levels, try putting about half a gram of psyllium husk in a coffee dose (in my case 20.5 grams, for a smaller dose reduce the psyllium pro rata)
If you do a side by side comparison with the same coffee and keep the same grind your shot time will blow out* so it won't be strictly comparable but it will show you what an increase in viscosity feels like in the mouth. If I do it again I'll play with the parameters and try to equalise extract level.
* A logical consequence of Darcy's law.
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Great insights in your previous post Lyrebird!Originally posted by Lyrebird View PostI am but a novice roaster and I do not claim to understand the process at all.
As you, I too am only in the early stages of my journey as a roaster. There is much that remains a mystery to me and much of my love of this craft is the education that accompanies the process.
I agree that Rob Hoos offers little by way of scientific evidence to support his theories, I am pretty sure he even acknowledges this in the first two pages of the book. He does, rather, offer many years of logged data by way of roast logs mapped with cupping results which ultimately form his logical reasoning.
Regardless, I subscribed to his theories as they seemed to support what I am trying to achieve as a roaster to which they have. I now consistently achieve sweeter roasts with wonderful viscosity following his theorems (to an extent).
Though I am now very interested in learning more about polysaccharides!
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Ah that's all good, but yeah it is interesting everything that goes behind the scenes on that level. Such a volatile process!
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I am but a novice roaster and I do not claim to understand the process at all.
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Hmm fascinating Lyrebird! Really cool stuff, so then in terms of applying that, how would one dissolve/release those polysaccharides, would then roasting generally darker sort of "make sure" they've been released/dissolved? (Sorry I don't know the correct term to apply here XD )Originally posted by Lyrebird View PostI don't think that theory holds water.
His syllogism appears to be
Melanoidins have higher molecular weights than their precursors
Molecular weight affects viscosity
Therefore viscosity is due to melanoidins.
But he presents no evidence for this and there are at least two good reasons to doubt it.
Firstly, melanoidin concentration is highly correlated with colour (See this paper: warning, 178 pages of organic reaction kinetics) so if melanoidins are responsible for viscosity it should also be correlated with colour. As far as I know this is not the case (or at least I haven't seen evidence for it).
Secondly there is a much more plausible explanation for roast profile influencing viscosity: in many fluid extracts of foodstuffs, soluble polysaccharides such as beta glucans have a very strong influence on viscosity. In the coffee bean, ~50% of the dry weight of green coffee is polysaccharide, mostly cell wall components, and it is well known that roasting results in solubilisation of the polysaccharides by both chain scission and sidegroup cleavage (see this article for instance).
I did also read that melanoidins are related to colour (browning process of the bean), but perhaps extending that maillard reaction phase ensures that more melanoidins are present/created (more time for aminos and sugars to bind together)? Just totally guessing! And perhaps it's not just the surface colour of the beans that's an indicator, but all throughout the inside that it colours out?
Am honestly just guessing here, makes for cool discussion!
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Originally posted by solace View PostFor me, a turning point in truly understanding the profiles I had been chasing (and also truly understanding the Maillard reaction with regards to roasting beans), was reading Rob Hoos book 'Modulating the Flavor Profile of Coffee'. Below is an article from the man himself that sums up some of this theory nicely, the article is geared more toward viscosity however what happens during this part of the roasting phase also plays a massive part in the resulting sweetness in the cup:
https://www.freshcup.com/the-effect-...ofile-on-body/
I don't think that theory holds water.
His syllogism appears to be
Melanoidins have higher molecular weights than their precursors
Molecular weight affects viscosity
Therefore viscosity is due to melanoidins.
But he presents no evidence for this and there are at least two good reasons to doubt it.
Firstly, melanoidin concentration is highly correlated with colour (See this paper: warning, 178 pages of organic reaction kinetics) so if melanoidins are responsible for viscosity it should also be correlated with colour. As far as I know this is not the case (or at least I haven't seen evidence for it).
Secondly there is a much more plausible explanation for roast profile influencing viscosity: in many fluid extracts of foodstuffs, soluble polysaccharides such as beta glucans have a very strong influence on viscosity. In the coffee bean, ~50% of the dry weight of green coffee is polysaccharide, mostly cell wall components, and it is well known that roasting results in solubilisation of the polysaccharides by both chain scission and sidegroup cleavage (see this article for instance).Last edited by Lyrebird; 1 November 2018, 11:55 PM.
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[QUOTE=Steve82;639720 I would get rid of the Yirg, it shines and is really sweet at a much lighter roast. [/QUOTE]
Steve how would you suggest I roast the Yirgacheffe?
Thanks
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You are more than welcome Gil.
I don’t really know anything about probes that are suitable for fluid bed setups. On the commercial gas roaster I use there are two K type probes attached to a Phidget 1048, this works out of the box with Artisan (after installing the Phidget driver which is straight forward) and seems to be a fairly common approach for Artisan users.
The probes used in that setup are 4mm wide x 100mm long and are RS brand from memory.
Heat Snob is unsupported in Artisan as far as I am aware.
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Thank you Solace for all your advice. It is most appreciated.
I see you are in Australia. What probe would I need to get to use the software? I presume the Heat Snob data logger wont work
Gil
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For me, a turning point in truly understanding the profiles I had been chasing (and also truly understanding the Maillard reaction with regards to roasting beans), was reading Rob Hoos book 'Modulating the Flavor Profile of Coffee'. Below is an article from the man himself that sums up some of this theory nicely, the article is geared more toward viscosity however what happens during this part of the roasting phase also plays a massive part in the resulting sweetness in the cup:
https://www.freshcup.com/the-effect-...ofile-on-body/
As for Artisan, I use that software when roasting on a commercial roaster. It is fantastic software given it is free and rivals the likes of Cropster both in accuracy and functionality. Below is an example of a profile I use for the Indian Elephant Hills which results in a super sweet cup with great 'mouth feel'. Note the aggressive reduction in heat which translates to an aggressive decrease in RoR (Rate of Rise), keep in mind this was roasted on a gas roaster, I believe your roaster is a fluid bed therefore the way you approach the profile is going to be different:
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Thanks for the advice and suggestions which I am going to try. I need to do some research on the "mallard" phase.
Has anybody had experience with the roasting software on https://artisan-scope.org
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The Indian Elephant Hills and Columbian Volcan Galeras Especial have produces huge amounts of sweetness in the cup for me! The Elephant Hills been the standout when it comes to grades of sweetness.
I don’t know your roasting equipment however you can achieve greater sweetness by extending out the maillard phase of the roast. I achieve this slightly backing off the heat from yellowing (pretty much when I get the bread smell). The trick here is to still have plenty of momentum heading into first crack.
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From that blend and given what you said about finish temps, I would get rid of the Yirg, it shines and is really sweet at a much lighter roast. The Gambella on its own should be just about perfect around 5°C from 2nd crack start in a 12 min air roast. I regularly use the Gambella by itself for milk drinks around this roast depth and its excellent, loads of complexity and if the roast is spot on can be REALLY full in the mouth in a dried fruit sweetness way. Something like 20g dose / 32g out in 32 seconds at 90°C.Originally posted by GilR View PostHi Steve
I use an Artisan 6 from Coffee Crafters and roast to around 220c. Second crack generally occurs around 225 and up.
I am currently roasting Brazil Bourbon 2/3 with 1/3 Ethiopian Yirgacheffe and Gambella but it lacks mouth feel. I mean sweetness and fullness in after taste.
I am looking for something that is smooth to the taste and rich aftertaste. We drink flat whites
. I don't want a strong taste that sometimes can lead to a bitter taste
Dimal, maybe I need to try Indian
Thanks
Gil
If you want to dilute it, try 50 / 50 post roast blend with Brazil pulped natural or as Mal said the IEH. Either way it will have massive amounts of body / rich thick mouthfeel.
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Hi Steve
I use an Artisan 6 from Coffee Crafters and roast to around 220c. Second crack generally occurs around 225 and up.
I am currently roasting Brazil Bourbon 2/3 with 1/3 Ethiopian Yirgacheffe and Gambella but it lacks mouth feel. I mean sweetness and fullness in after taste.
I am looking for something that is smooth to the taste and rich aftertaste. We drink flat whites
. I don't want a strong taste that sometimes can lead to a bitter taste
Dimal, maybe I need to try Indian
Thanks
Gil
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