Using the damper on the Cormorant

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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LBIespresso
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#1: Post by LBIespresso »

I would like to hear the thoughts and theories on using the damper on the Cormorant.

For anyone not familiar with the Cormorant, its damper separates the flame of the burner from the drum and is not related to the fans. I have included 2 images below. One is of my disassembled Cormorant (Long story but worry not, it's all in once piece now) and the other is a closeup of the damper sitting on top of the burner without the drum which spins directly above it. In the image it is partially open but I think one would only have it 100% open or closed.




My experience: In an online class with Scott Rao, he told me to just leave it open 100% of the time and not to mess with it. That was what I did for a long time but after taking it apart and putting it back together I starting thinking more about it and I figured I would test it out.

So I roasted something that I have over 100 batches under my belt. The way that I always do and then another batch with the damper closed but made all of the gas adjustments at the same temp that I always do. I just cupped my results and there was a clear difference.

I don't know if I should expect that difference to be bean specific or generally be true most of the time or what. So for Cormorant owners out there: How do you use the damper (In a repeatable manner, not loosey goosey roast by feel kind of way) and for non-Cormorant owners: Whaddayathink?

Please discuss while I sip a pour-over from the better tasting roast :wink:
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akirapuff

#2: Post by akirapuff »

So how was it different? Roast was better? For me when I close the damper I ended up using alot more heat to get the same roast. So I leave it open all the time. How about you?

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LBIespresso (original poster)
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#3: Post by LBIespresso (original poster) replying to akirapuff »

Rather than hitting it with more heat I applied the same heat and made the same adjustments (by BT) that I used in my normal open damper roasts. I know it is impossible to only change one factor but I wanted to try to change as little as possible. 165 is open and 166 is closed



Both were good but the open was more sweet than acidic and the closed was more acidic than sweet. It would be nice if I could apply this going forward to anything new that I try but I am well aware that things rarely work out that way...thus my question. :D

I did drop the closed roast 1 degree earlier as it looked about to take off on me but 1 degree less a little over a minute more into the roast I figured balanced each other out enough.
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Jasper_8137
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#4: Post by Jasper_8137 »

I have a Huky that has a similar setup. I always keep it open until I hit first crack, then close it to stretch my develop time without raising my BT too quickly. I've never not done this so am not sure how much of a difference it makes.

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LBIespresso (original poster)
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#5: Post by LBIespresso (original poster) »

That's similar to what I'm thinking about. Maybe closing the damper to replace the lowering of the gas that took care of the hump/flat spot in the ROR before first crack. This might serve the dual purpose of giving me a more effective gas dip when I need it as well as a slightly longer development time.

I am just thinking out loud here and hoping that if I need it, someone will step up and tell me how wrong my theory is :lol:
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bshaw3852

#6: Post by bshaw3852 »

I have a cormorant. I have nowhere near the experience as many on this forum, but I like to tinker. I had a honey process coffee from Colombia Aponte and could not get good results with an open damper/diffuser. My last batch of it, I tried a closed damper and it tasted great, so from then on all my honey processed coffees are with it closed.

I also tried in batch change - charge with it open and close it about 3 min in. I didn't really like the bean, so it was mainly to test. I dumped the batch, tasted like ashtray.

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LBIespresso (original poster)
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#7: Post by LBIespresso (original poster) »

Happy to see someone else on experimenting with their Cormorant!

Next time you see some green that you want to order, let me know and maybe I and others will order some too so we can compare notes.
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glf
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#8: Post by glf »

I'm curious, bshaw3852. Why does your delta MET drop precipitously and delta ET shoot nearly straight up at damper close, if, as I'm assuming, you have the typical set up of MET probe through the back handle and outside the drum while the ET is inside the drum through the chute's lower bolt hole? I would have thought the more indirect heating of the bean with the damper closed would increase the heat first outside the drum. But I could have this totally mixed up!

This is an interesting thread!

bshaw3852

#9: Post by bshaw3852 »

Here is one of the latest purchases of green, a red honey, so it should give me some challenge to get something good: https://happymugcoffee.com/products/cos ... y-luzmilda. I bought 10 pounds, so about 10 chances to test closed vs open damper.

I placed my MET probe through the drop handle, yes, however I have a 9" 1/8" rtd probe in there. So, it goes in quite far, about 2/3rds the way in above the drum. I didn't think too much about placement, but it seems to give me good response there.