Thanks sincerely for the comment Aaron - it's appreciated.
I have heard some people say that fluid bed is brighter. You even said something to the affect of drying .vs. malty etc, slow the roast down a bit then. You can generally control that aspect fairly well (unless it's just a bright coffee) with the method most the time.
'K - brighter but controllable - that makes sense.
'Malt' was a reference to how they treat brewers malt (sprouted barley) for
caramelization by not over-drying.
<TL;DR> The inevitable long-winded circumlocution
In a former decade I was very involved with brewing & the beer industry & I happen to be a science-geek as well. So at one point I did some studies of the Maillard reaction after reading lots of papers on the topic. As a result I find nearly all of the popular article reference to the Maillard reaction annoyingly inaccurate.
Louis Maillard was a very imaginative French chemist circa 1912 who described a hypothetical (and still unproven) set of reactions that could leave to a
SPECIFIC type of "browning reaction". But not all browning is Maillard browning. Most of the oompa loompa's writing, even very detailed descriptions, fail to understand basics.
Maillard browning happens between simple sugars & di-saccharides (only reducing saccharides with a terminal carboxyl end, NOT sucrose) and free amino acids (usually from proteins), REQUIRES water for the strecker degradation (but too much water acn limit temps). The rate is very dependent on the temperature (mostly from ~80C to 140C (where even water vapor is practically lost), depends greatly on the pH as well (generally higher rates of formation at higher pH, not always), and the specific amino acids & sugars. Maillard's description addresses broad classes of thousands of potential chemicals - not specific reactions.
Caramelization reaction is between sugars and the amines (NH2's - NOT amino acids). It has similarity to one of the early steps of Maillard (the amine nitrogen attach to the carbonyl groups) - but cannot produce the same range of flavors - just a basic one-dimensional flavor range, and lots of brown color. Commercially they produce caramels by heating sugars with a little ammonia - no amino acids. This results in, at first, the sort of sweet, hot compounds we think of as caramel candy, but then as the reactions progress all sweetness is lost and you just end up with a soluble coloring agent used in cola & Canadian 'whisky' (I use quotes to avoid leaving the impression this stuff is real whisk[e]y) as well as other foods. Some amount of caramel is produced in any Maillard reaction, but
caramelization is NOT Maillard.
Fatty acids (often produced by heating triglycerides) can react w/ free amino acids, create a similar carbonyl nitrogen substitution, produce brown colors and a great range of flavor - but
fat+amino reactions are NOT Maillard.
Then there is enzymatic browning - the common example is when the phenolic compounds in a sliced apple oxidize and brown in when exposed to air & phenol-oxidase enzyme.
Enzymatic browning is NOT Maillard..
Also there is another sort of browning reaction - carbonization. If you simple heat starch or sugar w/o any amine or aminos at all - this initially browns, then this leads to a more rapid extension we call 'charring' somewhere above 400F.. Basically you wreck the hydrogen bonds in the starch and produce 'charcoal'. Again -
NOT MAILLARD AT ALL.Maillard is about sugar+amino acid reaction, not fat+amino, not sugar+simple-amine caramelization, not enzymatic browning, not starch browning. Not all browning is Maillard..
So blogs like this ....
http://www.chefsticks.com/searing-maillard-reaction-and-deglazing/andpop-science sites like this ...
http://www.scienceofcooking.com/maillard_reaction.htmare"mostly wrong". . The color &
fond of seared meat is a chemical reaction, and there are loads of amino acids available in the meat surface, but the only reducing saccharides available are from the tiny amount of glycogen locked tightly in the muscle cells, vastly reduced after slaughter and certainly not significantly released by cooking. To put this in perspective, a 1lb steak has about as much sugars & Maillard product potential as one 1/30th of a tsp of sugar, and most of that is locked up inside the meat - not at the surface. Yes there is a LITTLE Maillard product formation, but most frond is from fat+amino acid reactions. Shaking on some cornstarch + baking soda (for higher pH) on your roast before searing makes a profound difference b/c it's dramatically 'upping' Maillard products to the fat+amino browning.
Taking it home - coffee beans have water, starch, oils and proteins, so we expect several of these reactions are taking place in the roast. You'll get caramelization at a higher rate at modest temps, then more emphasis on Maillard products before 1st crack, then only after 1C is there much oil exposed for any possible fatty browning. Somewhere after 1C there is also starch browning & the potential for real charring.
</TL;DR>
You are worried about drying the beans more? You are heating them up to 425 degrees or so.. yer gonna dry them out bud.
My point is that you don't want them bone-dry before 1st crack, and you may want to retain some water vapor in the roasting chamber rather than blow it straight out rapidly. . Moisture is necessary for the maillard reactions. Believe it or not your beans are still leaking some internal moisture from inside as they hit 1st crack & that this is important for flavor development.
I havent compared the two methods really. I may if I get time, do a run through my behmore of say 12 oz and run in the artisan and see if I can tell any differences in them. Im sure there will be as the methods are way different but I'll see. Sorry bud I am not roasting 10 batches though.
Any details would be appreciated. Yeah - I've never been one who believes you can get the same roast on differing hardware - too many variables change. Getting the same roast on same hardware is hard enough.
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This is the sort of thing I'm considering as a flavor issue
https://www.youtube.com/watch?v=TjVas7jbOUI&ab_channel=MillCityRoasters%2CLLChttps://millcityroasters.com/roaster-news/airflow-settings-use/The Mill City guys are considering how airflow impacts drum roasting (IIRC that's BoldJava in the back seat narrating).
So they start the drum roast with just a modest airflow to encourage an even roast by convection ,then as they approach 1st Crack they but up the airflow.
Several sources talk about removing the "charry" flavor of some no-fan drums by adding a blower. I'm pretty certain that's what I am tasting on my SC/TO, tho' I used the word 'tarry' above. If you taste the bitter brown 'varnish' that accumulates on your hardware you 'll know what I am referring to. i just don't want it on my beans.
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IMO air popcorn poppers are poor roasters (tho' a reasonable starter position); I'd interpret my long-ago air-popper experience as ...
= must modulate the rate of roast by change the load of greens amount, or use a variac.
= results are clean (less charry/tarry) b/c of the air-flow (no smoke deposition).
= results are very even due to (air) convective heating.
= results are often brighter (more acidic) b/c the beans are roast so fast [in my popper experience] so that the interiors are more raw and acidic.
= results are a bit 'plain' (lack of sweetness & complexity) b/c they dried out too much to allow enough development of Maillard products.
IMO the SC/TO has the following characteristics
= must modulate the rate with load and on/off or proportional heater control.
= results are not clean (more charry/tarry) b/c of the smoke re-circulation to the beans.
= results are sufficiently even but requires the stir-arm to be properly adjusted.
= results can be roast thoroughly (neither too bright, acidic, nor too flat and baked ) but this requires adjusting the load size & profile.
= results can exhibit good sweetness & complexity (does not over-dry beans as much as a no-controls popper)