Roast temperature and profile on 2 kg roaster

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
ontum
Posts: 87
Joined: 12 years ago

#1: Post by ontum »

Hello all,

I recently acquired an Ozturkbay OKS-2 coffee roaster that roasts 2kg batches. I roasted two batches but both batches did not have a lot of sweetness to the coffee.

Can anyone help with a good starting point for a temperature swing and profile.

On the first roast I dropped the beans at 200 C and the bean temp dropped to 150 C. In 6 minutes the roast came up to 170 C and I hit 1st crack. Way to early.

The second batch I dropped the beans at 175 C and the beans temp dropped down to 138 C at about 2 minutes. It rose up to 158 C at first crack and 8:40 into the roast. I pulled the beans for cooling at 10 minutes and a temp of 168C

The only control of temp bean temp that I can see is the if the propane burner is on and the exhaust flap flow. I feel like the bean temp should rise higher in that amount of time. Should I try smaller batches? Both batches I have tried were 2 kg. I am looking for a good starting point to lean this new to me roaster. Thank you for all the help.

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Boldjava
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#2: Post by Boldjava »

These would be my suggestions.

1. Your temps are not coming back correctly. They are reading about 80-85*F too low at given your reported first crack. Where is your thermocouple and how is it being read? Onto software or merely onto a PID display?
2. Start with 3/4th's capacity and just keep using that size till you master the roaster.
3. 8:40 for first crack is fine. What is just as important is how you got there.
4. Do you have an on/off switch to control heat or do you have a means to adjust the BTU application?
5. What kind of quality greens are you roasting? Are they fresh? How much per pound/kilo did you pay for the greens?
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LMWDP #339

ontum (original poster)
Posts: 87
Joined: 12 years ago

#3: Post by ontum (original poster) »

Thank you for the response. I must say that a big question mark is the beans. I do not know the age or elevation of the Honduras beans that came with the used machine. I received around 50 lbs of these beans and plan to see how good I get the roasts with these beans and then purchase known quality beans to hone in on better roasting. My intention is to dive into this roaster and learn as much as I can in about two months. This this machine is being donated to a none-profit camp in British Columbia that will use this roaster for their own coffee needs of about 30 lbs a week, and even sell beans in their general store.

1. I believed this to be the biggest issue thus far. Everything I read shows a rise in BT up much higher than up to the 170 C that I am getting. My first idea is that I need to reduce the quantity of beans, but I wanted to inquire here first before I waste more beans. There is a thermocouple for the BT at the left of the center shaft of the drum and I believe this drum rotated clockwise. So I believe the BT is taking the temp at the upswing of the beans. Sound right? The only other thermocouple is at the exhaust after the air flap control. The only readouts I have of temps are at the installed PID displays.
2. I will do this.
3. Good to know.
4. The PID controls an on/off of gas, and I have not seen an adjustment for more BTUs. I will get the propane tank filled to make sure it is at full pressure and capacity. I will also look harder for an adjustment.
5. Mentioned above. Can you recommend a good bean to work with but doesn't cost too much is I waste them? I would expect that I would want at least another 25 lbs. Currently I purchase beans for my home roasting Behmor at a local shop called Mr. Green Beans. They may able to steer me to a good bean.

Thank you for the help.

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hankua
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#4: Post by hankua »

There's a dealer in NY state, I'd give him a call as he has a reputation for being helpful.
http://www.adkcoffeeroasters.com

ontum (original poster)
Posts: 87
Joined: 12 years ago

#5: Post by ontum (original poster) »

Okay, so we have tried several more roasts. A couple at 3 pounds and one at 5 pounds.

The best roast numbers wise was the 5 pounds. Here is the temp/time log.
We left the exhaust air flap open 55% the entire roast.
0 Minutes - Drop with air temp at 175C
1:00 - 137C BT
2:00 - 131C BT
5:00- 145C BT
7:00- 158C BT
8:30 - 168C - First Crack
10:00 - 181C BT - Drop beans to cool.

The beans bottomed out at about 131C. Is this too high? Is our problem that we are starting the beans at too high a temp? Should we try dropping the beans with roaster at like 150 C? Or is there another problem?

Our 3 pound roaster were too quick. We dropped the beans at 175C and they finished within 6-7 minutes. We got a faster rise in temp with the smaller batches, but they finish too quick. We experimented with opening the exhaust more and less, but cannot slow the roast enough. First crack happened around 170C-160C.

Is it just that we need to lower the starting temp of the roaster? Or is it just the beans are are using?

Thank you for the help.

ontum (original poster)
Posts: 87
Joined: 12 years ago

#6: Post by ontum (original poster) »

Should I try different starting temperatures of the roaster?

Or just get new beans? Any other thoughts?
Thank you.