New to gas roasting - please help! - Page 2

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
ShotClock (original poster)
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#11: Post by ShotClock (original poster) »

Thanks for the feedback. I'll try holding the gas until DE next time, then cutting a little more aggressively in the second half of the roast. I'm having a bit of an issue with the regulator on my hose - seems like i can only get 28mbar at the burner. I have a new hose on the way, hopefully this will allow me to get to 37mbar.

All batches are 400g, with the same espresso blend at noted in the first post. Also maybe worth noting, I'm roasting in my garage, but I'm the doorway with the door open - this is a pretty cold environmental temperature, probably around 40-50F for the last couple of days.

My warm up routine is currently full gas until BT of 400 or so, then turn off the gas, cool to 300 or so, then warm up to the charge temp with the gas setting that i plan to use at charge.

This particular green is slightly on the cheaper side of what i buy, probably around $6/lb. Recently I've been buying mostly espresso blends and Ethiopian naturals. This coffee has the advantages of damaged packaging, and being something that I'm not particularly fond of, while having 10+lb to hand. This would be a painful process if these were beans that i really wanted to drink... Anyway, I'm hopeful that i can get to reliably drinkable coffee in a few more sessions.

Marcelnl
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#12: Post by Marcelnl »

Try limit your changes to one variable at the time until you understand the impact of it, changing both charge temp and duration of gas setting makes it difficult to interpret the effect each change has.
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ShotClock (original poster)
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#13: Post by ShotClock (original poster) »

Today I cupped both of yesterdays roasts - the first one was undrinkable: extremely bitter and roasty. The second was okay: mellow acidity, a bit of sweetness, a bit of bitterness in the finish.

I also tried another two roasts, again with the same parameters as the previous day.

The first was a total bomb - I stalled completely during 1C, then accidentally cut the gas completely etc.

The second actually went somewhat according to plan:



I charged at 350 again, and didn't cut the gas until 310F at 5:30. I tried to do all of my cutting between this point and about 370F, but found that I ran out of room at the low end too quickly - the regulator adjuster seems to have a lot of backlash at the "top" part that is required to get below 10mBar. Has any other Cormorant user got a nice hack for this?

Also, I'm thinking that I would be better off using more gas in the first half of the roast in order to reach DE with higher RoR, and leave more room for manoeuvre in the second half. Hopefully I'll have a higher pressure regulator soon that will allow me to try.

Thanks again for all of the help and advice!

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JohnB.
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#14: Post by JohnB. »

What regulator are you using coming off the tank? Does your Cormorant have the early burner or the larger one. 37 mbar built in regulator or 50 mbar? I roast 454g batches & charge between 380° & 390°.
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ShotClock (original poster)
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#15: Post by ShotClock (original poster) »

Thanks John. I got a Weber hose and regulator from the hardware store. I presumed that any low pressure regulator should be fine, but it appears to top out at 26mBar or so. The burner is the 37 mBar model. The previous owner had no issues with it, so I assume that this is an issue with the regulator on the hose.

Can I ask how you manage to get below 10mBar - does your adjuster have any backlash in it? If I drop the gas to, for example, 5 mBar, I have to hold it constantly or it will just spring back to 10. It doesn't seem to be malfunctioning, so I assume that I'm just doing something wrong...

I will also consider higher charge temperatures. It seems like I am still on the low side of Cormorant users.

Marcelnl
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#16: Post by Marcelnl »

I could not get good results on my Huky until I started using a 50mBar regulator, more power at the front end allows you to taper off power more gradually without losing momentum.
Regulators are not that great at very low pressure, my regulator wonks out at around 5mbar too.

You will need to check if the burner can handle the higher pressure, my Wok burner could not cope with it, the IR burner for the Huky could.
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JohnB.
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#17: Post by JohnB. »

ShotClock wrote:Thanks John. I got a Weber hose and regulator from the hardware store. I presumed that any low pressure regulator should be fine, but it appears to top out at 26mBar or so. The burner is the 37 mBar model. The previous owner had no issues with it, so I assume that this is an issue with the regulator on the hose.

Can I ask how you manage to get below 10mBar - does your adjuster have any backlash in it? If I drop the gas to, for example, 5 mBar, I have to hold it constantly or it will just spring back to 10. It doesn't seem to be malfunctioning, so I assume that I'm just doing something wrong...
I use a 0-5 psi adjustable regulator bought off Amazon. Opened 1.5 turns I have no problem getting 50 mBar. No issues with low gas adjustments as I can dial it down below 5 mBar & it stays although I hardly ever have a need to go that low. If your roaster has the old burner that came on the earlier models like mine you should definitely consider upgrading to the newer, larger burner & the 50 mBar regulator. I swapped both as soon as they became available as I always felt that the original burner didn't put out enough heat to roast large batches with the control I wanted.
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mkane
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#18: Post by mkane »

Your 171° TP says up the charge temp a bit. You then might not need so much gas at the start.

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JohnB.
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#19: Post by JohnB. » replying to mkane »

Even with a 380°F charge he'll need to use more then 25 mbar to get through drying a bit faster with a 400g+ batch. Particularly if he has the small burner. With my 454g batches & a 380°F charge temp I move from the 25 mbar/fan 5 preheat setting to 37-40 mbar/fan 6.5-6.8 about 15 seconds after charge. This typically gets me to 300°F BT in the 4:15-4:30 range.
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ShotClock (original poster)
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#20: Post by ShotClock (original poster) »

Thanks for the tips as always.

Mike - are you using 2mm TCs to get a higher than 170F TP?

John - was it a simple job to swap the burner and regulator? I will probably swap the burner if I still have problems with power. I guess I'll see how things are when I get to roasting in my garage at 10F in a month or so...