Fresh Roast SR800 - 1/2 lb Air Roaster - Page 21

#201: Post by **MNate** » May 20th, 2021, 4:34 pm

mtbizzle wrote:I'm confused by a first crack start at BT 375, that is barely into Browning for me, using SR800 and K-type probe into bean mass

Is the probe rarely immersed in the beans, more often mostly air / some beans? In any case, if you learn your landmarks and it works, it works!

Yes, immersed the whole time. The beans have a lot of loft to them, the probe reads cooler. If more compact, it reads hotter. At first I thought this would be a reading error but when hercdeisel said turning the fan down is the only way to increase the bean RoR when the heat is already near max, and I tried that a bit, I realized that's got to be right. The compact beans trap more of the heat, and therefore receive more of the heat, likewise the probe.

375 first crack? It's often more like 365, depending on the bean. And the hotter I start the heat after soak, the more I really can hear the crack.

I'm going to keep using the probe mainly because I want to stop the roast at a certain degree, +-2. Even if I don't hear good cracks, or things look uneven, if I go too high it tastes awful to me, and if I stop there with an uneven roast, it's still pretty ok.

I'm anxious to see if IowaBoy will roast with me this summer as he lives close by. I feel like he has a better grasp of the nuance.

And I also think I need to get better beans... but making these cheaper beans taste ok with my unrefined approach is pretty encouraging.

#202: Post by **mtbizzle** » May 20th, 2021, 4:56 pm

Interesting, I always get FC (9.5" Razzo, K type probe into the bean mass, 8oz = 227g batch) around 395-410. A few example roasts, just to compare as I find the differences interesting. I haven't found a roast 'style' / 'recipe' that is reliably giving me good results yet, but I think I'm getting closer these days. (The strange jumps in the first image, are due to a broken probe, the wire is exposed)

#203: Post by **Iowa_Boy** » May 20th, 2021, 10:19 pm

I wish I could say I had this all figured out, but I am beginning to wonder if that is even possible, or if at some point it's just a limitation of the roaster.
I couldn't help myself, and decided to buy the manufacturer extension tube in addition to the V4 12" Razzo that I have. I feel for the washed beans I roasted (Guatamala Antigua, Costa Rica Tarrazu), the results are uniform and excellent with both. Just easy to roast beans. With natural beans, I think the HRS (manufacturer) extension has the edge because I feel there is better and more uniform bean movement with the batch size I prefer. Is it perfect? Nope. Here is my most recent roast:

Disclaimer: This looks a bit better than it really is, because I have the curve smoothing (I think that is what it's called) set pretty high in Artisan.
In any case, I am still not sure I have the drying phase figured out.
This roast was: Preheat to base temp of 360".
Then use Fan 9 Heat 1 for 2 minutes.
As soon as I start to see ROR peak and begin to decline, increased heat to 6.
Then decrease fan throughout roast to keep ROR steadily declining. During FC, may need to increase heat by 1 or so to avoid ROR crash.
I am still getting some tipping on this roast, though far improved from a few months ago.
If you look at my curve, and the ones from the last few pages, I really wonder if the big ROR drop after if peaks is a problem. To blunt that drop, you really need H7, or maybe H8 to maintain the ROR momentum. But it doesn't seem like the natural beans can take that sudden increase in heat.
So the problem I can't seem to solve - how to dry naturals without any tipping/scorching, resulting in an aftertaste for me.
Because the glass can't store heat like a drum roaster, I really wonder if the preheat is helping or not.
I am tempted next roast to start from cold, do 9/1 for a few minutes, and see if ROR peaks at a lower level, and I can more gradually increase the heat during drying.
FYI - I consistently get FC from 395-410 on my Uxcell 3x300mm probe. So it seems like we are all getting different FC temps.
MnNate - Definitely would be fun to do some roasts over the summer! Though I may have switched to a drum roaster by then.

#204: Post by **mtbizzle** » May 20th, 2021, 10:30 pm

Iowa_Boy wrote:o blunt that drop, you really need H7, or maybe H8 to maintain the ROR momentum. But it doesn't seem like the natural beans can take that sudden increase in heat.

If you look back at your roasts, ones where you had a similar start, does the turn of the ROR curve usually come around the same time? If so, in anticipation of that time, you could try ramping heat up from 1 to 8 (as a guess) at set intervals, (to choose random times) you might start at H1 30s before that time, and end up at H7 or H8 30s after that time

Jim White's profile involves --
* F9h1 @ 0:00
* H2 @ 1:00
* H3 @ 1:10
* H4 @ 1:20
* H5 @ 1:30
* H6 @ 1:40

As an idea, you could check to see if that smooths the heat increase a lot, by checking the base temperature using both techniques, to see if it makes the base temp (heat output) change a lot less sudden

May 20th, 2021, 10:37 pm

That's an excellent idea. Yes, the ROR peak is always at the same time, close to 2 minutes. Here is another roast from the day.
Please ignore the flick/crash at the end. Ugh.

#206: Post by **Iowa_Boy** » May 29th, 2021, 6:56 pm

Today's roast. Preheating on 9FH1 until temp is stable. I am keeping heat pretty low throughout the drying phase. Overall seems to be working fairly well and pretty happy with how it looks.

#207: Post by **mtbizzle** » May 30th, 2021, 11:14 am

Iowa_Boy wrote: Today's roast. Preheating on 9FH1 until temp is stable. I am keeping heat pretty low throughout the drying phase. Overall seems to be working fairly well and pretty happy with how it looks.

That certainly looks pretty from Artisan! Looks similar to J White's approach. Let us know how it tastes! I'll definitely keep at this approach, seems like the temp profile is pretty replicable

Are you using Razzo 12 or manufacturer extension here?

May 30th, 2021, 1:43 pm

Thanks!
That roast is the manufacturer extension. I have both but am finding I get more even roasting with the manufacturer extension, especially for natural coffees. Bean movement is better during drying.

#209: Post by **jfjj** » June 1st, 2021, 9:27 pm

Wondering if anyone had any experience combating the crash and flick with the SR800. I have a Rwandan bean Kivubelt Lot 9 that is notorious to drop right after FC. I have some examples, but I'm curious on your approach to deal with the crash. With the drum roast is seems increate air or dropping heat prior to the crash helps with FC but if you increase fan or drop heat on the SR800 you crash your temp. I've read that some crank the heat during FC to fight it off but I've tried a few times and it's either to meticulous or I'm missing the timing on doing that.

June 1st, 2021, 10:26 pm

Not sure, it's a tough one, the issues you mention about adjusting heat / fan late are definitely barriers

Check out the charts and profiles in the rest of the thread, may give ideas on how to get temp and fan in a good place, sub 10 ROR after FC, as it seems like adjusting heat/fan after FCs will cause a flick / crash, unless.you want to go dark