miKe wrote: "I've found the early pre-tanning stage just as important as the start of 1st to end of roast stage. Too short time before tanning can lead to grassy/green aftertaste while too long inhibits good caramelization latter on I believe. I use about 4min drying stage (to my 300f). Then there's the main setup ramp tanning through browning. It's amazing how varying the ramp rate will alter the cup, same total roast time. Have done many comparison roasts in the past. Most Kona I've settled in on about 25f/min ramp tanning to start of 1st. Now I slow it down to 15f/min for a couple min then 10f/min final ~minute and a half my ~445f end of roast usually about 11:30. (which is about 5f before anticipated 2nd). Unless it's Kona Peaberry then a different overall faster profile usually about 10 to 10:30min. Cooling target 2min to 125f or less." If I understand correctly, what you describe above is a constant ramp upward toward the end without throttling back. Is this correct? Do you only do this for Konas or a certain type of bean? Respectfully, Eddie
I cannot speak for Mike, but reducing the heat after first is necessary to avoid running too fast toward second. You need enough heat input to prevent the bean temperature from falling. A falling temperature after first will not ruin a bean but will kill the brightness. Between those extremes, it is up to you to decide your preference. All roasters have a different response to heat input. A heavy wall drum with a large bean load cannot respond quickly to changes in heat. You have to anticipate the heat requirement minutes ahead of time. Fluid bed roasters with a light bean load can respond in a few seconds. Profiling does not have to be babysitting a roast and tweaking the temperature every few seconds. With my toaster oven drum roaster, I like a constant heat input from cold start to finish for dry process Brazils. I set the heater at the wattage requirement for the intended finish ramp, then leave it untouched during the entire roast. The initial heatup is slow until the elements reach maximum temperature. The maximum ramp is 18C per minute at 80C bean temp 5 minutes after startup. At 200C just before first, the ramp has declined to 9C per minute, about 16 minutes after startup. There is a brief decline to 7C during first then a return to 9C at the finish at about 18.5 to 19 minutes total. This is a quite fast finish ramp, so I terminate the roast near 220C bean temperature for a city level. This "profile" results in enhanced sweet chocolate flavor and preserves what little brightness there is in the bean. With wet process beans, I do a faster heatup, but then stall the temperature near 125C for drying. After that it is full heat to 180C where I reduce the heat in one or more stages to achieve the result I want for the particular bean. -- ---------- <Snip> <Snip>
From: homeroast-admin [mailto:homeroast-admin] On Behalf Of Eddie Dove Sent: Saturday, December 02, 2006 3:22 PM <Snip> important as the start of 1st to end of roast stage. Too short time before tanning can lead to grassy/green aftertaste while too long inhibits good caramelization latter on I believe. I use about 4min drying stage (to my 300f). Then there's the main setup ramp tanning through browning. It's amazing how varying the ramp rate will alter the cup, same total roast time. Have done many comparison roasts in the past. Most Kona I've settled in on about 25f/min ramp tanning to start of 1st. Now I slow it down to 15f/min for a couple min then 10f/min final ~minute and a half my ~445f end of roast usually about 11:30. (which is about 5f before anticipated 2nd). Unless it's Kona Peaberry then a different overall faster profile usually about 10 to 10:30min. Cooling target 2min to 125f or less." <Snip> <Snip> ramp upward toward the end without throttling back. Is this correct? Do you only do this for Konas or a certain type of bean? <Snip> Constant ramp rate from tanning to start of 1st yes (ie ramp rate of bean temp rise not applied heat temp). Usually between 20 to 30f/min depending on the bean. My current "main" profile (using past couple years). Note: first batch of session I pre-heat the Rosto to ~250f then cool to ~100f, same approx cooling temp as cooled batch. "Over sized" 1/2# batches. (Compared to stock Rosto 1/4# desinged batches) Target temps: 200f @ 1min (heater voltage usually 120 to 125v start, dropping to 102 to 108v ~150f ~25sec point depending on ambient) 250f @ 2min (usually maintaining same 102 to 108v or slightly adjusting) 275f 3min (usually couple volt bump to heater) 300f 4min (usually another couple volt bump, tanning stage begins) 325f 5min (4 to 6v bump, now up to 110 to 118v to heater depending) 350f 6min (often up to 120v to heater by now, browning stage begins) 375f 7min (sometimes need more heater power, sometimes not depending on ambient) 400f 8min (usually need 2 to 4v more to heater, 1st crack usually about now, often drop heater voltage 1 or 2v) 415f 9min (usually a couple v heater voltage bump back up) 430f 10min (usually backing heater v off a few) 440f 11min City+ (often continuing dropping voltage a couple v, depending) 445f 11:30min LFC (very common finish point for Kona, Centrals, Island etc) 450f 12min FC (early 2nds) 455f 12:30 FC+ (common Sumatra finish, used to go lighter but found like Indo's a bit darker, a few seconds of 2nd) 460f seldom go this high bean temp. For my espresso blends I usually go to 450f but a slower mid and finish but same start ramp, ~15min total roast. Use 20f/min tanning to start of 1st ramp, straight 10f/min 400f to 440f, then 5f/min 440 to 450f end of roast. This very slow finish ramp 2nd kicks in a bit earlier. I used to routinely use a finish "hold at final temp" for 30sec or so but don't now, though still do at times, depends on what the beans tell me they want from smell, sound, look etc. Kona Konnaisseur miKe mcKoffee URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path. To know I must first not know. And in knowing know I know not. Each Personal enlightenment found exploring the many divergent foot steps of Those who have gone before.
Mr. mcKoffee, I want you to know that I truly and sincerely appreciate you taking the time to entertain and answer my questions. I am taking this information and applying it to learning and in the last week I have gained even more understanding and applied it to my roasting yesterday. Again, I really appreciate you sharing this information and the reasoning for such. Sincerely, Eddie On 12/3/06, miKe mcKoffee wrote: <Snip>
miKe, Thanks for the profile......always learning. One comment to those that aren't instrumented to this level.......an increase in voltage at a higher bean temperature does not necessarily mean an increase in heatup rate as compared to a corresponding increase in volatage at a lower bean temp. In response to comments about slowing the roast after 1st......I have found that slowing at the beginning of first is beneficial (after prompting by several long time roasters). Mike (just plain)
Ken, Thank you for the information. This is helpful. Eddie On 12/3/06, Ken Mary wrote: <Snip>
I also use a PID'd Rosto. Here are 3 profiles: miKe mcKoffee's as described above and 2 that I use. You can see that miKe reaches 300F in 4 minutes while I'm closer to 5. His total roast time is 12 mins vs my 15 min (note I made a typo on the graph fro miKe's time to FC). I also roast smaller matches (6.5 ozs as opposed to 8 ozs. - I cannot seem to get 8 ozs to move enough in my Rosto and the 6.5 oz batch gives me 5 roasts per 2 lb bag). I'm going to give miKe's profile a try but I thought it might be helpful to see the graphs...http://coffee.nccs.biz/graph.jpg-Marc On 12/3/06, Eddie Dove wrote: <Snip>