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Micro stall when roasting
Hi everyone. I will start off by saying thanks for this forum; it is a super valuable resource for home roasting advice. I really appreciate all of your help and advice thus far.

Q: When I achieve 1C I begin to, or have already, ramped down heat/ramped up fan to slow roast and give me the 3-4 minutes additional roast time needed to develop sweetness in the bean.

However, when doing this, I have sometimes seen the BMT slow to a crawl and even drop .1 or .2 degrees for a moment or two (NOT 1 or 2 full degrees). Is this acceptable? I haven't noticed any detrimental effects to the roast result, but then again I don't know what the roast would be like if I hadn't "micro-stalled"it.

Any advice here? Am I getting less-than-desirable results with this action?

Any help is good help.
Hottop B-2K w barryR thermocouple mod, Mazzer Mini /Super Jolly burrs, Salvatore E-61 group machine, Aeropress, French press.


threwitallaway wrote:

... I have sometimes seen the BMT slow to a crawl and even drop .1 or .2 degrees for a moment or two... I haven't noticed any detrimental effects to the roast result...

Nate, this type of "micro-stall" happened to me as well a couple of times, and I did not detect any detrimental effects on the quality of my pulls.

Ciel... seeking Heaven in my cup with ................................................................................................................. EXPOBAR Brewtus II - MAZZER Mini E - MAHLK?NIG Vario - GeneCafe - RAF-1 Extreme (Modified B-2 HOTTOP) - BellaTaiwan XJ-101
Rate of rise is a great variable to follow, but one of the features one sees in an over-sensitive recording system, such as un"damped" Artisan with uninsulated probes, is the considerable fluctuations that occur in bean and even environmental temperature. This can be minimized by software adjustment, but it underlines the fact that what one is observing is a combination of real-time events and the interface between them and the observer. That interface may be faithful to those events, produce aberrations, or just be "off" a bit.

The answer to your question: Don't let it bother you. The real answer is in the cup. Trial and error is an essential part of our ongoing learning process.
Happy roasting!
Barrie (San Diego, CA)
"So much to learn, so little time."
Hottop 2K+., Artisan, Jura Capresso ENA 3 (i.e. espresso).

I was on my way to start a topic nearly identical to yours, here. Hope it's OK to resurrect this thread... maybe you've worked out some kinks and can share?

I have a similar question/problem dealing with these "micro-stalls"

Maybe you, or someone else here, could take a look at my two recent roasts and give some advice?

Here are pics (particularly the graphs "12-1-15 ... ".TIFF's)

First one is a Peru, 1 Lb batch. And it's not noted on the graph, but I also did a partial drop at 9Min/430F (which turned out better in the cup than the final drop, but both have a nasty taste...)

I'm currently trying to adapt to my new probes (pic "probeplacement1.0"), and have temporarily placed them... where you'll see them in the photo. I just did this to see what the reading would look like, before I start drilling. Still looking for recommendations for probe placement.

As I've recently added datalogging probes/Artisan to 1K drum roaster, I've noticed a decrease in quality in my final cup. My last couple graphs seem to indicate some "micro-stalling"... and I'm wondering if that's contributing to the nastiness in my cup.

My whole reason for the "upgrade" was because I was sick of having these phenomenal, one-off roasts that I could never replicate.

Didn't see pics, said Google drive folder was empty. The micro stalls are dependent on 1) roasting outside in cold weather, OR 2) ramping heat down too far during 1C, or 3) Both

I too have seen a decrease in cup quality when I get micro-stalls but I personally believe they are part of the larger problem of too low of an RoR after 1C. I addressed that in another thread a while back and the consensus was no lower than 6?/min (BMT Delta) RoR to keep roast functionally developing. Anything that resembles a very slight or straight line roast curve in the final stage of development will likely have an adverse affect on the beans and subsequently in the cup. Also, a long development time after onset of 1C will diminish flavor and acidity.

Hottop B-2K w barryR thermocouple mod, Mazzer Mini /Super Jolly burrs, Salvatore E-61 group machine, Aeropress, French press.
insatiable ONE
I got a roast that finished to light when I opened the door to try that same theory. To lower the heat right before first crack & try to slow the fan speed some.

Perhaps time to upgrade my equipment in the near future.
While I try to do a ROR of 5C/m coming into 1C and then slowing to 3-4C/min for 2 min thereafter, on one occasion a while ago I had a power failure right before 1C and everything shut down. Rather than throw that roast away, I cranked it back up later to 210C and just held it there for 2 minutes. It tasted fine to me in spite of all this, although I'm a total newbie to all this, I must say.

In my very limited experience, I do find that a 3-4 day resting period after roasting is beneficial, and brewing, or course, can have a very significant impact. My newbie perception at this point is that those are more important than micro details in the roast profile.
So many beans; so little time....
Because of this bump post I noticed this thread today and I can say pretty sure that with today electronics available to commercial measurements, 0.1C degrees fluctuation coming from a K type TC are pure noise, not related at all with actual temperature or bean thermal activity, which is of much bigger magnitude, 3-4 C.
Just think that TC4 resolution is 0.3C, so you read either 200, either 200.3, either 200.6, nothing inbetween... to understand that 0.1 could be the result of an averaging at most, but not a real temperature variation you can measure.
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