Managing my Cormorant

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

#1: Post by Almico »

I'm in need of a couple of new coffees and ordered a bunch or samples to try. Most of my importers supply 230g (1/2#) samples. I would love to roast 100g samples, but I can't get reliable enough data, so 230g it is until I can figure out something better.

My bean probe is in the door and bent 90*. It is not fixed and floats on and in the bean pile. It's about halfway from the door to the drum paddles. FWIW, I keep the diffuser selector "in" for the entire roast.

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Here are a couple of roasts from this last session:

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After warm up, and from the second roast on, I have to turn the heat all the way down to 1mBar. If I left the heat on, I would hit dry in 2:00. Not good. I can't turn the burner off like I do on my 5kg roaster, because lighting it back up mid-roast is not reliable.

As you can see, with a 250g charge, I don't have to turn the heat up until 2:00 into the roast.

I found 250g needs 25mBar to get going and hit 1C with 8-9 minutes, but I can't turn it up that high, or again, I'll hit dry way too fast. SO I found that turning it up to 10mBar at 2:00 stops the RoR from dropping too much, then a little boost to 20mBat and then 25mBar to push through dry and get some heat energy into the beans.

Then after dry I drop it down to 20mBar again and push the ramp to just before 1C where I drop it to 10mBar for a light roast. Fortunately, all my roasts on this roaster will be light roasts because all I use int for is sample roasting.

So this process has been yielding some pretty good results, and some pretty ugly curves. I'm not really sure how to manage it better. It's possible I need a thicker probe. The 2mm one I'm using seems too fast. If I left the heat on at charge, the BT would race to 300*, but the beans would still be green, so obviously I'm still measuring a lot of air and not just bean. A slower probe might help.

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JohnB.
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#2: Post by JohnB. »

As I recall you told me you replaced the original burner with the later larger one. Considering your use why not switch back to the smaller burner?? Also if your burner doesn't ignite reliably you probably need to adjust the igniter position or clean up the contacts.
LMWDP 267

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Almico

#3: Post by Almico » replying to JohnB. »

I think I still need the big burner to get 250g to 1C fast enough. More power is better than not enough. I can always turn it down.

My issue is not with the burner as much as it is with the combination of retained heat in the roaster, the speed of the 2mm probe and the difficultly in positioning the BT probe. The paddles are so close to the door, that it is hard to get a probe immersed in a 100 or even 250g bean mass. I've considered taking the drum out and grinding the paddles down. This way I could put a 1" long probe straight in at the bottom of the drum. But that seems pretty drastic.

I need to try it on the slower drum speed too. I've been using the fast speed.

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JohnB.
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#4: Post by JohnB. »

Or sell it to someone roasting normal loads the roaster was designed for. A used Hottop B with a few mods would work well with the 100-150 gr batches you want to use.
LMWDP 267

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Almico

#5: Post by Almico »

If roasts are going to be repeatable, I need to work on roast "hygiene".

With my 5kg roaster, it is very easy to start every roast at any temperature I want. I tend to charge coffee at the same temp I plan on dropping. I don't know if that will work with the Cormorant, but before I do anything, I need to get my charge temps stabilized. On the 5kg I can set the air to 50% and the gas to 10% and the roaster will sit all day at 380*. I need to find that kind of equilibrium with the little guy. I don't like charging while the temp is moving up or down too quickly. No point.

The infinitely adjustable variable speed fan does not make it easy to set the air at exactly the same rate every time. You have to kick it back and forth and wait until it settles in on a number. I would almost rather have a 10, or even 5 position switch that would repeat every time. Maybe I need to replace the potentiometer?

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CarefreeBuzzBuzz
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#6: Post by CarefreeBuzzBuzz »

How many MM can you insert before it hits the paddles.
CarefreeBuzzBuzz
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Almico

#7: Post by Almico » replying to CarefreeBuzzBuzz »

I think maybe 7-8mm. That is why I have the probe floating and not fixed. There is not enough room for a sideways 2mm thick probe and a bean. If the probe was fixed, beans would jam. If the paddles were 3-4mm shorter, I could lock down the probe I have and maybe get more consistent data.

mkane
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#8: Post by mkane »

If were mine I would drill a new hole up a bit higher, nearer to 7:30 where the probe would be inboard just a bit, out of the way of the paddles. This still might not immerse the probe in 100g of beans being inboard a bit. Your grind paddles idea may be a solution.

I have plenty of experience dealing with very small probes and if toy don't mind ROR going through the roof at charge, fast tp and lot's of smoothing stick with them. I caved and went with 3mm probes and am quite satisfied.

It took me 700 roasts and something finally sunk in reading every thread available here @ HB. These small roasters hold the heat and a minute or so before 1C it needs to really come down or else you have no control. I would really like to get my hands on a big machine just for feel.

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Almico

#9: Post by Almico »

mkane wrote:If were mine I would drill a new hole up a bit higher, nearer to 7:30 where the probe would be inboard just a bit,
You can see an unoccupied compression fitting about 4:30. That's the old BT position. Very little bean contact with 250g, less with 100g.

I tried installing it higher and bending it to point down towards the lower drum, but beans would jam and pop the door open.

I'm going to try some roasts this afternoon with the drum slowed down and maybe add heat sooner and allow dry to happen a bit earlier. As long as yellow is happening when it should, I'm OK with a fast roast for sample purposes.

mkane
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#10: Post by mkane »

You would think the people who manufacture this machine would have chosen an optimal TC location