Posted Tue Dec 23, 2003, 7:14am Subject: Z&D Update
I just have to say… I have been very impressed with the results from my Z&D lately. Initially, I was filling to the top fill line and roasting based on color to a medium brown (I use it for coffee only and don't like a dark oily roast). This would typically take me to about the 20 minute mark… with plenty of time left on the machine to spare. The results were quite good… but it did seem a little flat and missing something.
Lately, I have attempted to achieve a quicker roast by preheating the chamber for 5 minutes and using less beans. I measure out 115g which takes me to about the dark roast line. After preheating (with the lid on but no chaff collector), I dump in the pre-measured beans and add the chaff collector. My roast now takes between 9 ½ and 10 ½ minutes to achieve the same color as before. I still have a hard time hearing any cracks (almost never).. but have been successful a few times. Using my Yama primarily and manual drip on occasion.. I have been very happy with the result.
While I am not getting the maximum throughput out of the machine.. I do get enough to last me a full week…(which is my goal anyway). I am also very impressed at the evenness of the roast, lack of burnt beans (compared to my FR+), and lack of smoke. It is also pretty simple to clean up… which typically involves rinsing the chamber and chaff collector, wiping down the top and base with a dry cloth, and cleaning some chaff that escaped onto the counter.
I wish it would cool faster.. but all in all, I am pretty happy and this is the one I recommend to my friends who have similar requirements as I do.
Btw- I think I set a record today. In 18 minutes I roasted a batch of coffee, ate breakfast, made a pot of manual drip coffee (different beans), and cleaned up. I was quite impressed..
p.s. If anybody else out there has comments on roast times they achieve, I would like hearing from you…
I am heading home (parents) for Christmas and will have to resort to dial-up.. so I won't get to read my CG paper as I normally do. Wishing everybody a safe and happy holiday…
Posted Tue Dec 23, 2003, 12:14pm Subject: Re: Z&D Update
Hi John,
I am also a new owner of a Z&D. I also pre-heat the machine before roasting.
Before home roasting I was one of Peet's best customers so I am conditioned to roasts on the darker side. With preheating my roasts are taking about 20 minutes. I load the chamber somewhere between the dark and normal line.
One challenge I found was getting the warm and therefore soft gasket to seat properly. I plan to get a second cover so I can have a cool cover with gaskets and chaff cup in place while preating.
I think I am going to love this machine. The coffee is at least as good as what I was able to acheve with my HWP with a thermocouple and the ability to control the temperature. When the second lid arrives, I plan to mount a guide tube thru which I can place a thermocouple into the roasting beans. I may also try a tube for some sort of stethoscope arrangement. At present I don't hear cracks. When I open the machine to dump the hot beans into my cold HWP they are crackling like Rice Krispies.
You mentioned you would like faster cooling. My HWP will bring the beans to room temp in five minutes. It is a large load for the HWP so I have to pick it up and rock it back and forth to agitate the beans. I am not experienced with the Fresh Roast, but I would guess that you could use it for a bean cooler. The chamber is a smaller diameter so you may have to use a canning funnel to dump the beans into it without losing some.
After I get the thermocouple into the beans, I'll probably be looking at controlling the temperature.
Posted Tue Dec 23, 2003, 5:41pm Subject: Re: Z&D Update
PJK Said:
One challenge I found was getting the warm and therefore soft gasket to seat properly.
The first time I tried to preheat with the chaff collector I had the same problem. I don't believe a hot chaff collector is that critical and I have since been adding it after the preheat process (it is much easier to handle). I have the rubber gasket and chaff collector already combined and beans pre-measured. When I hit the 5 min mark, I pull off the top (which pauses the machine), leave the chamber in place, pour in the beans, place the chaff collector/gasket on top of the chamber, and put the top back on. I don't have as much problem with a flimsy gasket this way
When the second lid arrives, I plan to mount a guide tube thru which I can place a thermocouple into the roasting beans.
That would be nice. How much are they charging for an extra lid? I would like to see my temps as well... though there isn't much you can do to change them once the roast is in process.
At present I don't hear cracks.
Yeah, I can hardly ever distinguish the cracks over the motor/bean movement. I wish I could.. that would make it easier to establish repeatable times. Instead, I rely on color.. and ultimitely taste. Though in order to make it more precise, I need to stick with one bean for a while. Since I don't go through coffee that fast... it is easier said than done.
I would guess that you could use the Fresh Roast for a bean cooler.
Yes, that is a possibility... but the one thing I do like about the Z&D is that I can do it in the kitchen without making too much of a mess, if I start using another machine for cooling.. that would negate a major benefit of the Z&D.
It isn't that I hate the cooling... but I do notice the color change quite a bit during the first seconds/minute of the cooling process. If I am able to pinpoint times accurately, then I would be able to stop it 'ahead' of time.. and allow the residual heat to bring it into the zone. I do follow up the cooling process with a minute or so with 2 collandars. It isn't still cooking at that point.. but it allows me to filter out leftover chaff and examine my work...
DMHinCO Senior Member Joined: 9 Sep 2003 Posts: 17 Location: Denver, CO Expertise: I love coffee
Posted Tue Dec 23, 2003, 11:05pm Subject: Re: Z&D Update
I'll chime in here.
I like when my roast times (pre-cooling) are about 10-11 minutes also.
I take a pound and divide it into four equal parts. I roast near my computer and usually warm it up first. I can hear the Rice Krispies cracks very easily, so I just get up after about 30 seconds of cracking and press the cool button.
I commented here about chilling an extra roasting chamber for faster cooling. I can't tell the difference in taste, so I don't do that on a regular basis.
The Zambian AAA+ for brightness and the Sulawesi Toraja for body are my favorites from Z&D though the Salvadoran and Sumatran are also great. I should know. I used to run the tasting panel where we selected the beans to offer. Looks like the Panamanian is gone. It was the best lot produced in the country in the Cup of Excellence competition.
Tip Sheet for the Zach & Dani's Roaster at quovadimusllc.com/zad.html
Posted Mon Jan 12, 2004, 2:17pm Subject: Re: Z&D Update
Here is my latest Z&D update.
I installed a 3/16" copper tube through the top cover through which I could pass a thermocouple wire. It was an interesting first attempt. The copper conducted too much heat out of the chamber so I couldn't achieve temperatures greater than 395 degrees F.
I then replaced the copper tube with a section of 3/16" steel hydraulic brake tubing. This was a big improvement. I was able to reach temps greater than 415 degrees F. I made a graph of the result which I will attempt to attach. I call this the Z&D native profile. I preheated the machine and filled it to a level between the dark and normal fill lines. While I am calling this the native profile, I think the steel tubing removes enough heat to change the profile somewhat. The roast did seem slower than with the unmodified machine.
If you are not going to do anything to increase the heat from the main heater, I can't recomend the tube. The main heater is about 388 Watts so there isn't much heat to spare.
The good news is you can increase the heat. Lisa at Z&D cautions against using a Variac for fear of damaging the CAT. It turns out that there is a seperate heater for the CAT. (~330 Watts) I unpluged the main heater from the PC card and ran the wires out of the machine. I connected the main heater to a Variac. A 5 Ampere Variac is sufficient for this small heater. With this arrangment all of the machine except the main heater is running on line voltage. Use caution to insure that the machine is running before switching on the Variac.
With this arrangment the temperature can be ramped much more rapidly. With 138 Volts to the main heater the power is about 560 Watts.
I was able to clone Jim Schulman's Hot Top clone with more ease than I could with my modified HWP. The temp.control of my modified HWP is somewhat skittish while with the Z&D the temp ramp can be controlled smoothly with the Variac.
There is some refining to do. If I continue with the Variac I will bring the heater output of the board out of the machine to the input of the Variac to mitigate forgeting to turn off the heater before the blower. I am also considering replacing the heater with a 600 Watt heater and controling it with an incandecsent lamp dimmer. That will all fit into the Z&D case.
I also need to buy a second cover (~$20 from Z&D) to use for preheating. With my temp probe, assembling the chaff cup and gasket to the cover takes time during which I am losing heat from my preheated machine.
Posted Mon Jan 12, 2004, 3:27pm Subject: Re: Z&D Update
PJK Said:
If you are not going to do anything to increase the heat from the main heater, I can't recomend the tube. The main heater is about 388 Watts so there isn't much heat to spare.
Why did you opt for a tube? I would think it would be easier to just drill a hole in the top, re-seal with high-temp silicone and poke a thermometer through the silicone and screen. This method is used by others with poppers and FR+ with no/minimal heat loss (that I am aware of).
Interesting stuff on how you separated the heaters. Any pictures?
Posted Tue Jan 13, 2004, 12:44am Subject: Re: Z&D Update
Hi John,
I used the tube because my thermometer is a thermocouple with a bead probe. It is a flexable wire which needs the tube to guide it into position. I have used this method with success with my HWP. In fact I used a 1/4" copper tube with the HWP. The HWP as well as the air corn poppers and FR+ are fluidbed roasters which move a lot of air to agitate the beans. All that air requires a lot of heat (~1300 watts in the HWP). Most of the heat is being carried away by the exhaust air and the amount lost through the temperature probe is trivial by comparison. The Z&D is quite different. The beans, being agitated by the auger, do not require air flow for agitation. A very small fan wafts air past the small heater to carry heat into the roast chamber. The heat in the Z&D is more precious so any additional heat conduction path out of the roast chamber will be more noticeable than in a similar sized fluid bed.
Tonite I did take some pictures. I have some useable pictures showing my temperature probe. The pictures which were to show the connection of the heater leads to the PC board were out of focus and will have to be done again. I tried to download what I had but the camera and computer were not being tolerant of my inexperience. I'll give it an other shot in a less sleep deprived state.
If you take the bottom cover off the machine you will find a pair of wires from the heater (right under the roast chamber) going to the PC board. Note that Z&D uses black for common and white for hot which is opposite the electrical convention in the US.
Posted Tue Jan 13, 2004, 11:18am Subject: Re: Z&D Update
I havent taken my Z&D apart yet, but a 600w heater with a dimmer sounds like a good idea. I like the idea of putting the dimmer right in the roaster case. Do you have a source for the heating elements?
With the larger heater, we could probably roast more beans...at least up to the fill line. Right now I just fill up to the dark roast line.
Posted Tue Jan 13, 2004, 4:46pm Subject: Re: Z&D Update
Hi Scott,
When I read about the rumor that Z&D is going to bring out a more powerful roaster I called and talked to them about possibly getting the more powerful heater assembly. No luck there.
I think the only way is to remove the old heater from the unit and measure the heating element. After knowing the wire size and dimensions of the coil, a new heater can be fabricated by chosing the next size larger nichrome wire and winding a new heater using the length of wire which will give about 22 Ohms of resistance.
I have had the heater out but I failed to make any measurements. I will do it again. I think the wire size is about AWG #22 and the coil diameter is about 3/16". The resistance is 34 Ohms.
To get to the heater you first have to remove the roll pin in the shaft which drives the auger then work from the bottom. Remove the drive belt, then remove the screws which secure the metal part of the air duct which passes from the blower to the heater.
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