hbuchtel wrote:Thanks all for the great nuggets in this topic!

I'd appreciate hearing some more thoughts about airflow. I've been reading a book by the Japanese roaster Taguchi Mamoru in which he suggests limiting airflow in the 'steaming' (ie drying) phase to even out moisture differences in the batch. Any thoughts on this?

He is using a 5 or 10kg drum roaster with adjustable air flow- his suggestion is to close the airflow valve to 1/4 during this phase, then open it up 100% to pull out the skin, then close it again to 1/4 until 1st crack.

Regards, Henry

This sort of thing is very roaster specific; any commercial drum roaster will have airflow control as a major way of controlling the roasting process, and in combination with adjusting the heat source will be the way that you control roast temperatures. Most people reading this thread will not have any easy way to control airflow with their equipment, so it becomes more or less moot for them. Exactly how to do this and when (changes to airflow) will be very roaster specific. I think it is impossible to generalize on this in a way that would be useful for home roasters.

It also depends on what you mean by "airflow;" are you talking about passive air flow, or active air flow, as in the case of a Hottop where you can change the fan setting during the roast? For the Hottop this would be very academic in any event, because the heating elements in the Hottop don't have the capacity to get through the "drying phase" with any speed, so if you were to increase the fan speed early on in the roast, this would extend roast times to the point where you risk baking the coffee or flattening out the roast.

ken

"Edited" A draft of what I'd consider some of the basic roasting 101 information necessary to understand profiling. Or useful background information. Maybe a tweaked index like this with some live links to internal threads or external resources could avoid umpteen questions and complications with such articles like this one being attempted.

1. Understanding your roaster:
heat application/transfer rates
temp. adjustments
air flow
monitoring the roast, capabilities (visual/smells/sounds, BT,ET,MET,time)
identifying and working with/around shortcomings
why, what and how to modify

2. Bean basics:
what will cause different beans to roast differently
bean density and size
moisture content
measuring moisture content
considerations due to processing (WP, various DP, decaf)
identifying and culling defects pre and/or post roast

3. Roasting chemistry and reactions
"still thinking how to frame"

4. Sample roasting
what is it
when to consider doing a sample roast and when to just go for it
developing a sample roast profile
how to cup a sample roast
what is the cup telling me
useful sample roast info. to use for the main event

5. Roast Profiling
breaking down the roast profile
choosing a final roast level
Using the above info. from(1,2,3)
building a roast profile

6. The Roast
using the profile
data collection
monitoring the roast
adjusting on the fly.
cooling

7.Post roast analysis
visual
time after roast, when can I learn what
defect beans
cupping and identifying roasting related problems
adjusting the profile

I actually agree with Ken that what any roaster (and I'm dispensing for the moment with the distinction between home and pro roasters because Ghu knows I've had enough commercial roasts that flat out sucked) needs to work towards perfecting their craft is a thorough understanding of the roast process - what is going on with the beans at each roast stage, and how does one optimize those stages to bring out the desireable qualities in each origin. Even someone with a Probat or Diedrich who doesn't understand those things isn't going to be turning out coffee that we rave about. On the other hand, if you understand what's happening as the roast progresses, you can get great results with even the most minimal and/or simplistic equipment. The biggest advantage we, as home roasters, have over the commercial roaster is the freedom to experiment with tweaking different elements of the roast, since the only person who has to drink our mistakes is us. And drinking your mistakes is a good way to motivate yourself not to make that same error again.

I deleted the ad hominem posts, along with the posts deploring them.

-- Ken, your thoughts on how to profile and how to teach it are welcome, your thoughts on who shouldn't even bother trying are not.
-- Mike, this is an egoistic topic on my part; I'm looking for suggestions on writing an article teaching profiling to home roasters. If you find the suggestions given so far unsatisfactory, tell us why. But complaining that this is not actually an article on profiling is redundant.

Again folks. What needs to be in an article that teaches home roasters how to profile?

So far we have:

• Equipment Modifications How to control the heat and measure temperatures in various roasting devices. Maybe we can have a home roasting part of the FAQ. It would include DIY pieces and links to similar project web pages.
• General information on roasting Background knowledge about roasting that is true for all coffees and all roasting devices. This includes my personal favorite ...
• Diagnostics How to identify and fix roasting problems.
• Specific Equipment and Coffee tips This could be the best part of the effort if we had a good way of organizing and searching the available info.

another_jim wrote:Again folks. What needs to be in an article that teaches home roasters how to profile?

So far we have:

• Equipment Modifications How to control the heat and measure temperatures in various roasting devices. Maybe we can have a home roasting part of the FAQ. It would include DIY pieces and links to similar project web pages.
• General information on roasting Background knowledge about roasting that is true for all coffees and all roasting devices. This includes my personal favorite ...
• Diagnostics How to identify and fix roasting problems.
• Specific Equipment and Coffee tips This could be the best part of the effort if we had a good way of organizing and searching the available info.

The key to a good profiling article is to keep it short and sweet and about profiling. I'm thinking a Roasting 101 index like I posted above(with links to internal threads and external resources) might be a good and maybe necessary complimentary resource. The index could be simultaneously developed in another thread.

Myself I get lost in the machine specific areas. Like you Jim I'd love a write up that covers the universal truths with home roasting rather than the "what do I need to do to my roaster" articles, but then again those have a valuable place too but separate in my opinion.

Myself like I've said before I've learned (from others) that the beans should be exposed to the lowest possible heat to achieve the desired roast. For espresso I've been hitting first in 7-8 minutes, and then stretching the roast to finish in 4-5 minutes later (bbq drum). The espresso is still really good and the flavors far more developed than when I roasted very hot, hit first in 6-8 minutes and then finished the roast 3-4 minutes later.

I literally have the grill over 200F cooler (because I preheat everything but the coffee) for the roast and still get to first in the same time frame, the real difference is that the later part of the roast is more predictable.

I'm at a disadvantage in the Diagnostic arena, I'm just not that experienced yet beyond the very obvious markers. I really liked the idea of the Rate my Roast, but got the impression it was geared more at blend evaluations than roast quality evaluations. I would have jumped on the later because like Ken I live in very remote area and am often left to my do my own evaluations (and frankly I'm no cupper).

I'm following this thread very much for the "universal truths" that we all can learn from.

Sadly my only contribution is the be gentle approach (nothing new), it really does preserve the aroma and I would think (per Kens remarks) the beans structure.

Did this list die?

I haven't really followed this entire thread, but if the goal is how to "profile" a roast, I think there's only a couple of necessary things.

(1) Roaster capable of variable heat application
(2) Bean Mass Temperature measurement (in a good, fixed location)

To me this is all that is necessary. Getting #2 positioned correctly can take some work, and having your numbers or experience translate to another person's setup is probably where it becomes the heated debate we are seeing here. But with these elements anyone can start to profile their own roasts. From there it's more about trying out certain CONCEPTS in roasting, rather than trying out a specific quantitative numerical result.

Sure, inferior equipment means inferior numbers, but they should still mean something to that specific setup.

Um, the thread presupposes that your roaster is capable of profiling. The question is now that you have it, how to use it?

Due to this thread and a couple other threads I've recently followed on a couple other forum/lists. I now realize that the quality and quality standards of the roast are determined by the home Roaster(person) who is also the end user. Every home roaster(tool) is profile able. A usable (again determined by the home Roaster) profile can be developed by one or combinations of: sight, smells, sound, BT, MET, ET, volt meter/variac, watt meter, timer, various temp. adjusters (variacs, triacs, thermostats, rheostats,pid,valves) , manual on/off(as Jim mentioned, plugging and unplugging a unmodified popper during drying phase), length of extension cord, batch size, manipulating agitation, introduced air, ambient temp/humidity and computerized buttons. (I'm probably forgetting something). Oh ya, raising and lowering the heat gun.