germantownrob Senior Member Joined: 2 Dec 2007 Posts: 2,007 Location: Philadelphia Expertise: I love coffee
Espresso: Duetto 3, A Dead Oscar Grinder: Vario-W, Preciso w/Esatto,... Drip: Brazen Roaster: Diedrich IR-1, HT B
Posted Tue May 10, 2011, 7:21am Subject: Re: Question(s) on Toper Cafemino 1KG Roaster & Diedrich IR-1
My Diedrich IR-1 is a bit different, there is full control over burner level, air flow is always 20% through the drum which can be increased to 50% or 80%.
I drop in any where from 175-200c depending on bean and charge amount, I turn the burner off (if doing 1kg I will reduce burner to the lowest setting) until the turning point then I turn burner on and adjust to go through drying phase in 4-6min. During drying phase as beans start to pale and go yellow I open air flow to 80% to get rid of 85% +/- of the chaff. Once beans begin to yellow and drying phase has ended I put air flow at 50% until beans begin to tan to get rid of any excess moisture, from this point until FC I will adjust airflow from 20%-80% depending on what is happening with the amount off chaff still left. Once FC is approaching I will adjust heat depending on bean and how it will go into FC and once FC begins I open air flow to 80% and adjust depending on if I am going for a 3+min or 5- min finish.
Even though I have control over heat I am only doing minor tweaks to it once drying phase is over and I use air flow to do much of the control ET. I used to adjust the heat much more when I first started using the IR-1 but found these profiles where much harder for me to repeat compared to using air flow to adjust ET.
One other thing I do that the Diedrich manual suggest is to pre-heat to to 213c then adjust to desired drop in temp.
runaro Senior Member Joined: 12 Feb 2009 Posts: 21 Location: Norway Expertise: I love coffee
Espresso: La Marzocco GS3 Grinder: Compac K 10 WBC Drip: Hario Roaster: Toper Cafemino Gas
Posted Tue May 10, 2011, 12:24pm Subject: Re: Question(s) on Toper Cafemino 1KG Roaster & Diedrich IR-1
I usually roast 900g loads so the charge temp should be higher. I have had no problems with tipping or other burn damage on the beans, however with the second or third load of the day (when the Toper is really getting up temperature) I will reduce the charge temperature. Maybe having the heat source inside the drum (electric elements) will increase the possibility for tipping? In my quest for roasting knowledge I read that it is desired to reduce the drying phase of the roast and extend the time from FC to end of roast. So my strategy has been to have a high charge temp and much heat in the drying phase, then slow down before FC. Of course dependant on the hardness of the beans.
The quick increase in ET when opening the air vent is easy to explain, my ET probe is above the drum shaft and the warmer (lower) air is mixed with the colder higher air thus quickly increasing ET. The BT response to this action I find very slow. Maybe a combination of your strategy (air vent 50% open then 100% open around FC) together with switching burner on /off manually will get optimum control of the profile. I will test this on my next roast.
I wish the Toper had the possibility to vary the burner level, I have been thinking a bit about a modification of the Cafemino, but understand it is not so straight forward.
Whale Senior Member Joined: 12 Aug 2009 Posts: 114 Location: Montreal Expertise: I love coffee
Espresso: Vivaldi II, MCal,... Grinder: MXKR, Major, Mythos, Baratza... Vac Pot: Vintage Silex Drip: Press only, I don't do drip!... Roaster: Cafemino E and Poppery 1
Posted Wed May 11, 2011, 9:43am Subject: Re: Question(s) on Toper Cafemino 1KG Roaster & Diedrich IR-1
Of course, it may be (is) required to have a higher initial temperature to compensate for the higher mass. I always forget that I use my Cafemino at the bottom end these days. Not because it does better but rather because I roast many different type of beans. I am still experimenting a lot.
I do not have any tipping issue either. I just use a lower charge temperature to better control the profile. I find it much easier to correct a profile by pushing it up than bringing it down.
I personnally believe that the speed of the drying phase (BT<150°C) has little effect on the taste, but has a huge effect on the profile after. I find that too short (or long) a ramp to 1C is just as bad as too short (or long) a time after 1C. Thus my requirement to control the drying phase within certain margins. If one can control the profile after drying regardless of the duration and temperature of the drying phase and gets no roast defect, than one can charge at any temperature.
Unlike Rob, I control the roast (profile) with the heat input a lot more than the air flow. I tend to want to maximise air flow to get the chaff out. I find that the Cafemino is not great at extracting chaff. I think that is because of a somewhat weak air flow from the Cafemino fan. This also reduces the effectivness of the damper to control the ET.
I have installed potentiometer controled SSR's to control the heat input and also installed external heating. There was no means to control the heat input with the basic electric Cafemino. I am surprised to read that the gas Cafemino has not heat control either. It should not be too difficult to modify it by adding a needle valve and either a flow meter or pressure meter. It is not much more complicated that a barbecue... I think that the Diedrich IR-1 uses a needle valve and pressure gauge. Rob could confirm.
And like Rob, On the first roast, I pre-heat the drum, to 250°C and then adjust the charge temperature.
I do not have a good answer. On the roasters schematics the gas valve I turn looks to electronically control a gas valve coil where the gas line comes into the roaster. Yes to a gas pressure gauge.
I have a NG 1/4 turn shut off valve just before connection to the roaster so I tried to see if I could accurately change the gas line pressure in the roaster with it , I was able to with a little practice.
Whale Senior Member Joined: 12 Aug 2009 Posts: 114 Location: Montreal Expertise: I love coffee
Espresso: Vivaldi II, MCal,... Grinder: MXKR, Major, Mythos, Baratza... Vac Pot: Vintage Silex Drip: Press only, I don't do drip!... Roaster: Cafemino E and Poppery 1
Posted Wed May 11, 2011, 5:25pm Subject: Re: Question(s) on Toper Cafemino 1KG Roaster & Diedrich IR-1
I am sorry I got confused with another roaster. Actually it is the US Roaster's sample roaster that has what looks like a simple needle valve to control the gas pressure to the burners. The only difference between Rob's 1/4 turn ball valve and a needle valve is the resolution (accuracy) of the control. But as Rob stated with a bit of practice, even a crude valve would give more control.
I actually cannot find a decent close up picture of the control panel of the IR-1. Rob, could you please, post one? Is the gas input control the knob that is on the panel?
runaro Senior Member Joined: 12 Feb 2009 Posts: 21 Location: Norway Expertise: I love coffee
Espresso: La Marzocco GS3 Grinder: Compac K 10 WBC Drip: Hario Roaster: Toper Cafemino Gas
Posted Thu May 12, 2011, 1:39am Subject: Re: Question(s) on Toper Cafemino 1KG Roaster & Diedrich IR-1
I previously aired the idea to modify the Toper to be able to vary the burner input during the roast and got comments about probable improper combustion due to incorrect air/gas ratio. The toper has a gas regulator (Honeywell VR8304M) which cut of the gas supply when the set temp is reached. It is possible to manually adjust the flame by turning a screw, this is however a very impractical way to adjust the flame during a roast.
Whale Senior Member Joined: 12 Aug 2009 Posts: 114 Location: Montreal Expertise: I love coffee
Espresso: Vivaldi II, MCal,... Grinder: MXKR, Major, Mythos, Baratza... Vac Pot: Vintage Silex Drip: Press only, I don't do drip!... Roaster: Cafemino E and Poppery 1
Posted Thu May 12, 2011, 3:41am Subject: Re: Question(s) on Toper Cafemino 1KG Roaster & Diedrich IR-1
Of course you do not HAVE to do it. I believe that it would help controlling the roast.
Now for the improper gas/air mixture. I do not think that this is very of a concern. Again look at a barbecue (for propane) or at a gas kitchen range (for natural gas), both simply use a metering valve to control flow/pressure to the burner.
I would suggest that you should not attempt to modify or control the burners with the electronic pressure regulator/shut-off valve (Honeywell device). I you would introduce control you should install it downstream of the regulator. This way you retain all the safety features included in the roaster.
If you are not comfortable with plumbing or gas devices, I would certainly recommend that you ask a specialist to do it or assist you.
runaro Senior Member Joined: 12 Feb 2009 Posts: 21 Location: Norway Expertise: I love coffee
Espresso: La Marzocco GS3 Grinder: Compac K 10 WBC Drip: Hario Roaster: Toper Cafemino Gas
Posted Thu May 12, 2011, 4:33am Subject: Re: Question(s) on Toper Cafemino 1KG Roaster & Diedrich IR-1
Thanks for your suggestions Whale. Maybe some day I will modify my roaster to be able to control the flame. For now I will, as yourself, continue experimenting. The improved temperature monitoring and the Artisan software is a very nice tool to learn the tweaks of the Toper.
germantownrob Senior Member Joined: 2 Dec 2007 Posts: 2,007 Location: Philadelphia Expertise: I love coffee
Espresso: Duetto 3, A Dead Oscar Grinder: Vario-W, Preciso w/Esatto,... Drip: Brazen Roaster: Diedrich IR-1, HT B
Posted Thu May 12, 2011, 5:10am Subject: Re: Question(s) on Toper Cafemino 1KG Roaster & Diedrich IR-1
Whale Said:
I am sorry I got confused with another roaster. Actually it is the US Roaster's sample roaster that has what looks like a simple needle valve to control the gas pressure to the burners. The only difference between Rob's 1/4 turn ball valve and a needle valve is the resolution (accuracy) of the control. But as Rob stated with a bit of practice, even a crude valve would give more control.
I actually cannot find a decent close up picture of the control panel of the IR-1. Rob, could you please, post one? Is the gas input control the knob that is on the panel?
http://www.diedrichroasters.com/index.cfm?page=LabRoaster that is actually my roaster they used for the pic. When looking at the SS control box top right is the bean temp display under that is a toggle switch for pilot and burner on, to the right of that is the knob to control burner pressure. under that is 4 red switches that control Drum on, fan on, gas on, and a high temp limit reset switch.
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