Decreasing ROR Question

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

#1: Post by thestevenlee »

I am new to tracking roast profiles and roasting with an actual roaster that is not a HGBM set-up where I would simply time myself had try to hit my events by certain times.

I am roasting on a Quest M6 and typically charge 350g of coffee. I am 10 roasts in and feel a little more confident already, but obviously still have a TON to learn. My first few roasts were super fast, then super long. Now I can hit "most" of my event times, BUT my ROR is all over the place. I feel like if I charge and have an initial temp that hits my dry time, then I lose momentum to first crack and have to add heat. If I charge and have higher heat then I feel like I fly through my dry phase and have to much momentum that leads me to hit 1st crack fast at like 6min and dropping at 8min when I originally want to hit 1st crack.

I feel like my ROR drops really fast after charge, then almost stabilizes and plateaus, with the occasional decline and rise. I can post some profiles for future roasts if that will help you help me lol, but I figure I would ask before spamming images. I have charged at 390For 400F with the turning point typically 0:55 into roast at 190ish degrees. I know some people don't really look at ROR and mainly worry about event times, but I would like to work on having a steadily decreasing ROR.

Dokkie

#2: Post by Dokkie »

It sounds like there is not enough heat input at the start of the roast. Try the charge temperature that gets you the drying time you want, but give your heating elements more power. At dry end you can easily start decreasing the heat. This should prevent the plateauing of the ROR.

thestevenlee

#3: Post by thestevenlee »

I think my charge temp is to high and not allowing me to apply the heat I need at the start. I will try a few with a lower charge temp, but then apply more heat at the start.

Dokkie

#4: Post by Dokkie »

Yep, that is what I meant! Let us know if it works out!

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Almico
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#5: Post by Almico »

thestevenlee wrote:I think my charge temp is to high and not allowing me to apply the heat I need at the start. I will try a few with a lower charge temp, but then apply more heat at the start.
Agreed. Small roasters don't retain heat like their larger counterparts do. There is not much advantage to charging overly hot. Adjust charge temp so you're turning around at about 1:00 and at 170-180*F. Either turn the gas off at charge or keep it low. Then you need to find the right ramp gas setting, and time to engage it, in order to get to a decent DE time and to carry you through 1C. Ideally, you do not want to increase the gas, only decrease.

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Peppersass
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#6: Post by Peppersass »

What fan settings are you using? On my Quest M3, the roast will lose momentum if the fan speed is too low.

My Quest fan is operated through an Arduino/TC4 interface, so I can't tell you what front-dial fan settings I use. I generally start at about 30% of max speed, with is actually pretty slow, then bump up to 40% at RoR peak and 50% about one minute before DE. I leave the fan at that setting until just before drop, when I bump to max fan speed to blow off any remaining chaff.

I should mention than my M3 has 1/16" probes for MET (between drum and shell) and in the drop door. It also has probes for ET (1/8", stock position, opposite the trier) and exhaust (1/16" in the center of the exhaust tube.) I find it essential to manage heat with the MET probe rather than the ET probe.

That said, your M6 likely has very different air circulation properties than my M3. I have a solid drum painted black with a single row of holes drilled around the rear circumference. I also have the copper tube mod to pre-heat the air. If it's like the M3S, you M6 probably has a much drum perforation and a better air intake and pre-heating system. Does it have slats at the rear exhaust or did they finally remove those or find a way for them to restrict the exhaust less?

thestevenlee

#7: Post by thestevenlee »

I should mention that I am using the Mill City 50mm thermocouples in the stock BT and ET positions. Today I roasted a few 350g batches of coffee and tried to start with a lower charge temp. I was thinking that it may stretch out the TP as well to closer to a minute, but it was around the same as all the other roasts I have started with a higher TP at around 0:50sec. I may need to up the charge temp a bit because it took me a little longer to reach dry end on a few roasts than I would have liked. I found that I hit FC around the time I wanted, and a little later on a few, but nothing super crazy.

Image

This was a Colombian roast that I wanted to do a lighter roast on. I charged at 370F and let it soak for the first minute. After the one minute soak I turned the heat to 10 and had the fan on 0 (even though my fan still spins underneath on 0). At the end of drying I lowered the heat to 7.5 and turned the fan to 2. My first few roasts saw me fly through dry end, so I wanted to make sure I didn't do that. I will say that I stretched it out a little longer than I wanted to. At 9:00min I cut the heat to 5 and turned that fan to 3. About half way through first crack I cut the heat and cranked the fan to hight. I went a little past the end of FC because I wanted to stretch out the development time just a little.

I am curious how I can stop the sudden rise in ROR right before FC, and how I can fix the sudden drop of the ROR after I charge to make it a more gradual slope. I probably could charge this coffee a little hotter than 370 to get more inline to what I was aiming for. I went about a minute longer than I was wanting too thats because I went a little long in drying and in the mid phase.

This last roast I had a slightly shorter soak and higher temp on charge at 375F. It is also a different coffee. My Dry time was where I wanted, but the mid was a little shorter since I wanted to stretch it out and make it more of a medium roast. I hit FC .30sec faster than I wanted and dropped it faster than I hoped because I thought I heard an outlier for SC. and did not want to make this a dark roast. I wish I could have stretched it a bit more, but most of the beans looked nice and smooth. My ROR started to rise again at the end of the roast even though I was decreasing heat and increasing fan throughout.

Image

I appreciate the help. I feel like I need to anticipate changes better so the roaster has time to adjust with it being electric, but I also feel there are a few other things I am missing that you guys could help me out on.

@Peppersass My fan is always between 0 or 3 before I hit first crack to which point I turn it up half way through. My next roast I will start with a higher fan speed from the start.

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CarefreeBuzzBuzz
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#8: Post by CarefreeBuzzBuzz »

A couple of suggestions.

Program some simple buttons to mark your gas and fan changes in Artisan.

At the 9min mark you get two different results. In one you get ROR jumping way up and the other way down. Were there the same adjustments in both roasts?
CarefreeBuzzBuzz
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thestevenlee

#9: Post by thestevenlee » replying to CarefreeBuzzBuzz »

I will look at programming some buttons for heat and fan. The roast where it goes down at 9min was an additional fan increase to 4 instead of 3 according to my little roast book I have. I will say that there is usually an increase in ROR around FC.

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CarefreeBuzzBuzz
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#10: Post by CarefreeBuzzBuzz »

If you decrease heat and increase fan at the same time, it's hard to know what is going on since you are taking heat out two ways. Try to only do one at a time. Do you have sufficient quantity of one bean to practice with? My 2 cents would be get a fan protocol from other Quest users and then try to learn your gas first before you start adjusting for the fan.
CarefreeBuzzBuzz
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