Initial temp drop after charge funny, and recovery after TP

[alejandrooo]

Hi, everyone, I'm starting to get a bit more consistency with my roasts, but still looking for any suggestions to improve all the dips I still have:

https://goo.gl/photos/rvHKNpf48q7UpTNj7

It's been hard to get the ROR line smooth without making a lot of adjustments to keep control of it (definitely not a hands-off roasting experience on my Huky). 

Another issue is my TP is not dropping as far down as I'd like to 200 or less.  I charge at 400F and preheat above 400 for a while before dropping it down.  Wondering if maybe I need to stall out at 400 for a while to stabilize everything first....

I'm per an earlier post in this topic group having some yellow and green beans show up when clean out the machine after a roast.  Sounds like I need to keep the exhaust pipe angled up when I charge? 

Lastly, after a few consecutive roasts where I was feeling like I was making progress and getting more control, tonight it on the first roast just had a mind of its own and I couldn't slow down all the curves in my ROR.  It was a little windy on my patio where I roast.  I am covered on all four sides with walls, but there's no ceiling, so wind does blow around quite a bit on a day like today.  Could that be affecting my results?

Thanks and FYI on my Artisan set-up:

https://goo.gl/photos/etUC3jRLhWnh8Bdu5

[edtbjon]

While the perforated and the solid drum does behave in different ways, a Huky is still a Huky regardless of the configuration.
I use three settings for air and 3-4 settings for my heat. But the way to get to the 3-4 gas adjustments came from doing some 6-8 adjustments throughout the roast. Once I started to understand how the roaster worked and reacted to my adjustments, I could analyse at the graphs, looking for places where I could have made one single larger adjustment instead of 2-3 consecutive ones. Add some patience to your roasting experience and you'll eventually get there. Getting down to having a nice looking graph (not important) and very nice tasting coffee (VERY important) with 3-4 gas adjustments took me many months if not years.
With my solid drum I usually aim for a TP around 160F, which I get if I (with a properly per-heated roaster) charge at 280-300F with a 400g charge load. If you don't get your intended TP (from charging your perf. drum at 400F), simply lower the charge temp. Try 350F or even lower! (From my experience with the perf. drum it does need a higher charge temp, but nothing even close to what Mr. Li recommends in his instructions.)

[alejandrooo]

Helpful stuff, thank you! 

Do you mind sharing with me some of your own graphs where you've had good control so I can study how they differ from mine?  And do you mind telling me what % or v you have your airflow at throughout the roast? 

Lastly, do you feel it's important to be aiming for that 200 or below TP like I read in Scott Rao book and see in my many other friends' graphs who are very good with the Huky?  It seems a standard of quality and more important than initial charge temp

[alejandrooo]

Not sure how much this matter, but what's your sampling interval?  Mine is 4s and wondering if I should lower it to get quicker feedback....

[SusanJoM]

I've been under the impression that the Turning Point was irrelevant and that it mostly just indicates how sensitive your t/c is  -- something that won't change from roast to roast anyway....

I think the first data point of interest is EOD (End of Dry). 

As to "sampling interval", I think 3 is appropriate if you are using a Phidget.  It might be too fast if you are using a slower reader?  I'm not sure, but I've always used 3.

P.S.  Could you post your profiles here in the thread rather than linking them, so they are part of the conversation? 

[Brent]

I have a feeling that,  especially with the perforated drum, it won't take much wind around the Huky before it's going to effect what's happening in the drum.  I'm learning that the perforated drum is pretty sensitive to airflow. At least that's how it seems to me. Doesn't take too much continuous air flow to really affect MET.

As far as Tp,  I've read and heard a few different ways of explaining TP as most of us probably have. Roos way of explaining turning point worked well for me and I came away with thinking of it this way.
Bean temp starts going up quite soon after being dropped in the drum. Though the thermoprobe is showing a drop in temp because the drum just had a bunch of room temp beans dropped in it. Bean temp is going up now, probe temp is going down. They meet at your TP and both go up from there. So I agree with Susan that it doesn't really have a bearing on roast quality. My understanding is that it can tell you a few things though.

According to what I've heard from Joe Marocco (sp?) it can give you an idea of bean density for eg.  If your drop temp and charge are the same when roasting a few different types of beans, (different origins, or farms) a more dense bean will have a lower turn around temp than a less dense bean. Though I use volumetric measuring too. (If I'm remembering that name correctly? How much a given amount of beans weigh per volume measurement, IE cup, or liter)  Personally, I like to have an idea of the density of bean I'm roasting. I like that there's an area to calculate and record it in Artisan

According to Roos, as you get to know your roaster and a particular bean, the TP happening earlier, or later than expected, can give you an idea of how much initial energy you have going into your roast before you start seeing ROR numbers. Even though I don't yet know the Huky as much as I'd like, I'm finding this to hold true