Roast Profile Adjustments for Bean Density/Moisture

twiztedwords

I'm using professional roasting equipment for small batch roasting.  My roaster's max capacity is 10 kilo.  I have PID controls too.

My question is: How will a roast profile need to be adjusted to compensate for more dense beans (ie, high grown PNG, as opposed to, say, an Indian Monsooned Malabar).  Also, how does moisture content factor in to roasting?

Correct me if I'm wrong (or expand my understanding), but from what I understand, a more dense and/or moist green bean will require greater energy to roast.  I'm also guessing this would cause the rate of rise to be less during roasting, as well as the bean/atmospheric equilibrium temperature to be lower at the start of the roast just after dropping the beans.

How should a roast profile be adjusted to compensate for higher density and/or moisture?...like, a longer roast time, higher end temp, flatter curve, etc.  Once the bean drys out (I'm assuming around first crack) will the roast personality change?....like, a faster rate of rise, more difficulty in keeping temps aligned with the profile, a spike in temp at the end of the roast, etc.

Also, are denser beans better suited for higher temp roasts, such as espresso, whereas less dense better suited for cinnamon/city type roasts?

Any comments, links, resources, graphs, books, ANYTHING would be super helpful.  I'm not finding much on this topic.

Thanks

mycuppa

Phil, With all due respect, you need to draw your own personal conclusions from testing, taking notes, constantly reviewing records and cup tasting based on your own roasts on your own equipment. The problem with most people asking these types of questions is they want to read and find the instant answer or solution. This already creates a per-conceived mindset or expectation that blinds you to what is actually happening in the cup and on your equipment. Unless you have a raft of scientific measurement equipment like moisture meters and agtron, etc. how would you know if bean A is more moist or harder than bean B, other than supposing it is from reading somewhere that Ethiopians are harder than Indians as an example and of course there can be quite significant variations in roast profile on some types of roasters, e.g. batch 1 and batch 2 can be different. My advice - don't read too much into what other people using different roasting apparatus and different beans - it makes no sense or has very little relevance. Start from scratch, keep meticulous records, make notes and observations, capture times and temps and then cup the results 7 - 12 days later. This is the only way you will develop an understanding - someone roasting on a popper or other style of home roasting equipment really can't compare to commercial gear and beans from your US broker may be quite different to the same origin beans I use in Australia.

Brett H

on 1346220889:

Phil, With all due respect, you need to draw your own personal conclusions from testing, taking notes, constantly reviewing records and cup tasting based on your own roasts on your own equipment. The problem with most people asking these types of questions is they want to read and find the instant answer or solution. This already creates a per-conceived mindset or expectation that blinds you to what is actually happening in the cup and on your equipment. Unless you have a raft of scientific measurement equipment like moisture meters and agtron, etc. how would you know if bean A is more moist or harder than bean B, other than supposing it is from reading somewhere that Ethiopians are harder than Indians as an example and of course there can be quite significant variations in roast profile on some types of roasters, e.g. batch 1 and batch 2 can be different. My advice - don't read too much into what other people using different roasting apparatus and different beans - it makes no sense or has very little relevance. Start from scratch, keep meticulous records, make notes and observations, capture times and temps and then cup the results 7 - 12 days later. This is the only way you will develop an understanding - someone roasting on a popper or other style of home roasting equipment really can't compare to commercial gear and beans from your US broker may be quite different to the same origin beans I use in Australia.

Great question Twisedwords and fabulous answer Jeff!  :thumb:

UNM

density is an easy one to check (I think, correct me if I am wrong). take a 10kg batch and see how much volume it takes up in a container with graduated markings on the side. denser beans take less space. Might be worth logging this as part of the record keeping if you want to factor density into the profile over time.