Advice on High heat & drop temp
This is a discussion on Advice on High heat & drop temp within the Coffee Roasters forums, part of the Coffee Industry category; I am somewhat unsure of some roasting terminology and need some advice. I have often read that certain bean types require different heating profiles. When ...
- 12-08-2012 04:10 PM #1
Advice on High heat & drop temp
I am somewhat unsure of some roasting terminology and need some advice. I have often read that certain bean types require different heating profiles. When I hear "high initial heat" say for a Yirgacheffe, does it mean a higher drop temp or more gas during the initial phase of roasting? I would add the same question for "moderate heat throughout"? If I keep my drop temp the same and increase the gas, then I get to first crack too soon, and ultimately get to my finish temps too soon. I am of the opinion that I need to get to FC in the 9:30-10:30 range and finish temp about 3 minutes later. I would appreciate some feedback on this issue.
Also, when do you start the timer? Once the beans have all entered the drum or when you first start dropping them in from the hopper?
- 12-08-2012 04:10 PM # ADS
- 12-08-2012 06:36 PM #2
Bam, you need to give some details like what kind of roaster, drop temp, 1c temp, 2c temp, and the @ times you get to drying, 1c, etc. so the other forum members can make suggestions.
- 12-08-2012 08:29 PM #3
I am roasting on an Ambex YM-2. I have been varying my drop temp between 320-380*. I am reaching the turning point at 1:30 min at 150*. I then climb back to And reach FC beginning around 375-380* at 9:30-10:30 min and dropping at 12:30-13:30 min at 415-435*. I don't take it to 2C very often. I am wanting to understand if initial high heat should be accomplished from a higher drop temp or more gas through the drying phase.
- 12-09-2012 06:58 AM #4
I think going down to 150* might be dropping it too far down. Especially if you are finishing the roasts in 13 minutes. It sounds like you should maybe raise the drop temp, at least on your initial batch roasted for the day. I'd also consider giving it more gas during the drying process. You could also decrease the gas when you reach first crack to slow the process in that crucial phase.
I shoot for a 15 minute roast on our USRC unit.
- 12-09-2012 07:48 AM #5
- 12-09-2012 10:23 AM #6
Also..... it appears you are raising your temps an average of 26.5*/min. On our machine we shoot for keeping it at 20*/minute or less. (That translates to a climb of 1*/three seconds.) As first crack begins, I like to slow the process down further.
- 12-09-2012 01:56 PM #7
Thanks for the feedback Eldub. If I increase the gas and drop temp, isn't that going to get me to FC sooner? Then my time from FC to drop is going to be upwards of 6 minutes. Is that what I am looking for? Also, do you start your time clock as soon as the beans enter the drum or not until all are in the drum?
- 12-09-2012 04:11 PM #8
Start timing when you open the chute to put the beans in the drum, or once they are all in. It really doesn't matter as that's just a few seconds when the beans are cold. The place where seconds count is at the end of the roast with a few seconds one way or another being able to make quite a difference in your roast results.
Our standard drop temperature is 175C (350F) and we're shooting for 17 to 22 minute roasts depending on batch size and bean type.
Also for us we do keep track of the time to FC, SC, etc., but The Lovely & Talented Roast Mistress is primarily roasting to taste and smell, with appearance coming next and the time a distant last. Each bean is different. Sumatra roasts (for us at least) lots longer than Ethiopian or Colombian. It is a harder bean and takes longer to cook. A 23 minute roast isn't unusual, dropping the finished beans just as second crack starts to take off. All roasters are different, we have a cast iron drum and it takes longer to heat than steel, so that's a factor but six minutes to first crack is (again, for us) way too fast. A 13 minute roast, unless we're roasting 3kg in our 10kg roaster is way too fast. So there are a lot of variables.
For instance you've got a 2 kilo roaster but are you roasting 2 kilos? If you're sample roasting say, 500g, then the roasting time will be a lot different than if you quadrupled the volume.Wrinkles only go where the smiles have been -- Jimmy Buffett (via Mark Twain)
- 12-10-2012 11:51 AM #9
What amount in pounds of coffee are you dropping? This will have a large impact on your roast profile. I roast on a YM-2 and typically drop 4.5 pounds with the burners at 100%. I reach 300F in about 7 minutes, throttle the gas back to about 50% at this time, 1st crack at 375F in 11 miuntes and typically finish the roast up between 14-16 minutes.
- 12-10-2012 06:08 PM #10
On the other hand, I think you are giving it too much gas during the roasting process if you are making it from 150* to finish in 12-13 minutes.
So my advice would be to bottom out at around 230* and then to raise the temps no more than 20*/minute until reaching first crack and then cut back on the gas from there to coast to finish.
Btw, Razzo's advice sounds spot on to me.
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