New to gas roasting - please help! - Page 5

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
OldmatefromOZ

#41: Post by OldmatefromOZ »

drgary wrote:Do you mean it actually dips your ET or your ET ROR? I've not had good results dipping my ET but with much less experience than you.
Its hard to talk about Environment Temperature, where is it being measured, what is it actually measuring and is it useful?

With your perforated drum I have no problems believing what you say.

In my case im using solid carbon steel with a cast iron 2nd outer "wrap" so a little dip in my outer rear drum ET / inlet temp is neccessary when approaching first crack.

I think Alan (Almico) has said it many times drum roasts are about making a few well timed gas changes and that's it. Morten on TW podcast advocates 3 flame settings and ive been having my greatest success so far with this approach which also gives pretty steady Environment Temps.

My current thinking is that if you need to make more than 4 gas adjustments prior to first crack something is not set up right or far too much gas is being used at start, but i could be wrong for different machines.

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JohnB.
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#42: Post by JohnB. »

OldmatefromOZ wrote:My current thinking is that if you need to make more than 4 gas adjustments prior to first crack something is not set up right or far too much gas is being used at start, but i could be wrong for different machines.
Even four seems like alot. Typically I'll adjust the gas twice before hitting first crack (typically 390°+or-) & my ET (measured inside the upper drum area) stays above BT right to the end. Most of my roasts are in the City+ to Full City range & I don't let the ET climb above 440°F before drop.
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LBIespresso
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#43: Post by LBIespresso »

I too am still learning to roast, but, worth noting that the ET for Shotclock's Cormorant is above the drum. I found it to be just as useful but different from having it in the drum. My new Cormorant has the ET close to the trier in the drum and it is different but I use it in the same manner. Max ET outside the drum occurs near FC on either side depending on use of the diffuser (plate between the flame and the drum) the bean, and heat application. With ET inside the drum max has always been temp at drop. But I still use ET to see where BT is going and still look at ET ROR post roast to make sure I called FC right from time to time (as per Rao's "Best Practices").
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ShotClock (original poster)
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#44: Post by ShotClock (original poster) »

Thanks for all of the tips, lots of food for thought here. I'll update when I've had a chance to try some of these strategies.

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#45: Post by ShotClock (original poster) »

Another update, tried to implement some of these tricks to get something out of my DP Ethiopian without baking it.

Roasting was done in my garage with the door open. After yesterday's blizzard, it was extremely cold - around -10C or 10F.

My general approach was to extend the highest gas setting before the first cut, maybe 1 minute after DE, make fewer cuts before FC, then leave the gas slightly higher for more energy during FC, and try not to cut during FC to avoid a crash. I was hoping that the gas strategy would leave ET rising. Flat or falling ET was my main warning that I might bake the roast.

First batch (previous roast of this bean in the background):

Charge was 450g compared with 500g last time - this was to give me a bit more room as the weather was so cold. I gave it a gentle start for 30s before hitting the gas. This roast went mostly to plan, although the ET started to stall at around 8:30, which was followed by a small crash. The big rise in ET is me closing the damper, which seemed to save the crash mostly.

Second batch (first batch in the background):

This appears to have been a disaster, although I will wait to taste and see for sure. After charging at almost identical BTs, the rise after TP was far slower. I'm fairly certain that this is due to the weather, and the fact that the roaster cooled down too much between roasts. I increased the gas to 35 mbar rather than 30 to try and catch up, but was behind at every point. I stayed on the gas much longer, came in to FC with a bit more momentum, and didn't spot the ET levelling off during the start of FC. Dropped this one at the end of FC as it was crashing, maybe a bit under developed at only 13% DTR? Don't have high hopes for this, but I have certainly been wrong before...

Interestingly, no amazing fruit smells from the roaster today - hopefully that is all in the coffee rather than the air this time!

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CarefreeBuzzBuzz

#46: Post by CarefreeBuzzBuzz »

ShotClock wrote:Another update, tried to implement some of these tricks to get something out of my DP Ethiopian without baking it.
Not convinced you won't like the second one better. You have 25 vs 17 degrees after FCs. You might very well get more fruit from the second. Shouldn't be baked.

Please update to Artisan 2.4.6. Save your settings first. They will carry over but just in case. Go to Config>Stats. Check the box ∆F and on your graph you will see degrees past FCs. No more math. Start to compare you tastes on the same bean with this number.

Don't stress about a perfectly straight ROR line. Yes many claim it's better. I believe due to many variables in prep that to if you don't have a big flick which you don't then most people can't taste the smaller imperfections. If you want to start evaluate your curves, read the blog post on Artisan Analyzer and start to use that tool.
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#47: Post by ShotClock (original poster) »

CarefreeBuzzBuzz wrote:Not convinced you won't like the second one better. You have 25 vs 17 degrees after FCs. You might very well get more fruit from the second. Shouldn't be baked.

Please update to Artisan 2.4.6. Save your settings first. They will carry over but just in case. Go to Config>Stats. Check the box ∆F and on your graph you will see degrees past FCs. No more math. Start to compare you tastes on the same bean with this number.

Don't stress about a perfectly straight ROR line. Yes many claim it's better. I believe due to many variables in prep that to if you don't have a big flick which you don't then most people can't taste the smaller imperfections. If you want to start evaluate your curves, read the blog post on Artisan Analyzer and start to use that tool.
Thanks Michael - I'll try to remember to update Artisan, expert guidance here is very much appreciated.

Having just tasted both roasts as v60s, here are my thoughts:

- First batch: pleasant acidity, lacks some complexity and sweetness, not quite "fruity". This would probably have been better dropped earlier.
- Second batch: better, more complex acidity. Unfortunately, this is covered up a bit by a bit of a cereal type baked note. Nowhere near as bad as the last time, but there and annoying.

Next time, I think I'll try to replicate the first roast curve with a drop temp of around 400F.

Again, thanks for all of the help.

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LBIespresso
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#48: Post by LBIespresso »

Keep it up! You are making great progress in this puzzle that will never be solved but that will give you increasingly better coffee to drink and a fun challenge along the way.
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drgary
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#49: Post by drgary »

Looking at your latest description, I've been told by more than one expert roaster not to increase gas during 1C. Even if you do the Scott Rao gas dip, you return to a prior setting before the onset of 1C.
Gary
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What I WOULD do for a good cup of coffee!

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Brewzologist
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#50: Post by Brewzologist »

OP; Here's a theory for you to explore. I'm up in New Hampshire so know how hard it is to roast outside in the winter. (Which is why I don't anymore but I digress).

With the low thermal mass of the Cormorant and cold environmental temps I'm wondering if you're reaching a point after FCs where the low gas setting becomes overwhelmed by the external cold facilitating the apparent crash. In your recent profiles it's evident from BT you're carrying good momentum into FCs and not over correcting gas changes. But your ET has already begun flattening well before FCs which it shouldn't IMO. On my Huky I also have a probe outside the drum and it follows an arc during a roast, declining at the end but never becoming flat. That flat ET line makes me wonder if the Cormorant is struggling to maintain heat in general. Also when you close the damper temps shoot upward quickly, suggesting perhaps you've also been pulling in very cold air.

Is it possible on the Cormorant to close the damper part way during the entire roast to help hold in more heat? Yes of course you'll then need lower gas settings in general. If my theory is correct, this might be a way to better control the apparent crash at the end. eg. It's easier to remove heat on a gas roaster to control a roast than to add it.

If this theory proves wrong, the next thing to consider is you may have a crashy bean that's hard to control. I have some like this where a well timed gas dip approach before FCs works nicely when everything else has failed. But my bet is the cold is the culprit. HTH.

EDIT: See example profile below. On my roaster I have 2 ET probes; one within the drum and one outside. The outside probe is the thin black line at the top of the profile labeled MET. The inside probe is the red ET curve. It sounds like your Cormorant's ET probe may be somewhat similar to my MET probe in being outside the drum. Not saying you should strive to duplicate my roasters behavior as the specific location of your ET probe is different than my MET probe; just illustrating the arc I mentioned: