Sonofresco / Q&A / Tip & Tricks

[peter]

The Geisha has been pretty good; although a little risky, this was not a waste of beans. As a matter of fact -and don't tell Dave- it's nearly as good as what we cupped at his house last month.

This would be where Milo enters with a comment about pooching.



Good work, Steve!

[ScareYourPassenger]

This got me thinking about adjusting the flow with a variable regulator during the roast.

I did it on the cheap: a 0-10 psi adjustable regulator, an Ebay surplus magnehelic gauge 0-50 WC, and a handful of brass fittings from Home Depot. The regulator is good for only a fraction of it's total adjustment. 11 WC is less than 1/2 psi. The knob was too loose to permit fine adjustment so I wrapped electrical tape around the stem to give me enough friction to make it work.

Over 50 water column will blow the plug on the magnehelic gauge and vent propane next to your machine. If you try this, don't do that and if you do, don't smoke while you're doing it. If I keep this set up, I'll add a second fixed regulator for safety. It will shut off automatically when the pressure drops too fast. I'll also probably find a valve with a finer adjustment.

But I digress. I did a ramp up and drying phase, bumped the gas down to slow the roast, bumped it up again to hit first crack at 9:11, dialed it down to get a couple of minutes between first and second crack, and then ramped it up again to hit second crack at 12:48 and then finished the roast at 13:00.

The beans look and smell great. I make no claim as to the quality of this roast or this "profile." This was only an experiment to see if a cheap adjustable regulator would work in conjunction with the firmware of the machine sufficient to tailor the roast. The answer, so far anyway, is yes.

I'll post pics later tonight for anyone that's interested.

I am curious for sure, most of my roasts hit 9:15-10 in length. I have tried to lengthen them through adjustment of the valve but they don't taste as good as the shorter roasts for some reason. You should push a temp prob in there and log it.

[tyme]

I don't have a sonofresco but still I'd like to see the modification.
What  fuel valve does Sonos use? Like a Honeywell vr8xxx?

[sgreen]

Sonofresco uses a Robertshaw 722 series Uni-valve.

This isn't much of a "mod". I just bumped up the regulator on the gas valve to maybe 12 wc and controlled the burner output with the variable regulator off the tank.

[sgreen]

I did log the roast. Again, I'm a novice roaster and I haven't a clue as to what this curve should look like, especially in this roaster. I did get enough of an adjustment where I'm satisfied with this as "proof of concept."

Over a couple of back to back roasts, I was able to bring the burner output down enough to stall the roast but still ignite normally. I was also able to increase the temperature and the rate of increase beyond anything I can imagine as useful.

Bear in mind, this is all within the limitations of the safety features in the stock controller firmware. I have most of what I need to replace the stock control entirely, but based on what I'm seeing I'm not sure that is called for. All I wanted to do was slow the roast and control the time between first and second crack.

[sgreen]

And for the record, Bold J's Geisha was about the best coffee I ever had. If that's a pooched roast, it's a level of pooching that I aspire to.

[jspain]

And for the record, Bold J's Geisha was about the best coffee I ever had. If that's a pooched roast, it's a level of pooching that I aspire to.

Steve,

First of all B/Poocher is not in the same class when it comes to a "good ole pooch" controller that you've shown in your work! Nice job and I'm watching for pointers but, I'm even behind B/Poocher with my mechanical skills!

Your simple mods and description are a great idea and something that "I" might be able to attempt! I'll make sure the insurance policy is paid up first on the "man cave!"   

[sgreen]

I was willing to risk the garage. I never really liked it anyway.

[Burner0000]

I need help from fellow Sonofresco owners.  I have converted to Natural gas and here is the problem I've been having.  I have spoken with Sonofresco but I'd just like to get your take on this problem before messing with the roaster.  If I roast past #4 or City roast the roaster doesn't hit target temp and shows E3 code.  According to Sonofresco and the gas installer the roaster needs 7" water column to work properly which I assume I don't have because our residential gas pressure is a bit lower than that.  Sonofresco said I need to adjust my valve screw on the valve assembly approx 1/4 turn.  I'm gonna do this tonight or tomorrow.  Just wondering if anyone has experienced this and did it resolve the issue?

[Joe]

I think Chris had done something where they had asked him to adjust some screw. I would definitely do what Sonofresco asks and then if it doesn't work you could always keep contact with them and follow up. Eventually they will have you returning parts, if it doesn't fix the issue. Did you already go through all of the normal items such as MCU and thermocouple? Also I know this is gonna sound silly but of there is any "fuzz" on the plenum where the thermocouple is? You should always keep that clean, this eliminated 90% of any issues I have ever had, in fact I think I replaced probably 2 thermocouples unnecessarily because I didn't realize how important that was.

[Burner0000]

I think Chris had done something where they had asked him to adjust some screw. I would definitely do what Sonofresco asks and then if it doesn't work you could always keep contact with them and follow up. Eventually they will have you returning parts, if it doesn't fix the issue. Did you already go through all of the normal items such as MCU and thermocouple? Also I know this is gonna sound silly but of there is any "fuzz" on the plenum where the thermocouple is? You should always keep that clean, this eliminated 90% of any issues I have ever had, in fact I think I replaced probably 2 thermocouples unnecessarily because I didn't realize how important that was.

What's the MCU? Yup I just replaced the thermocouple and I have the entire roaster vented out so nothing es exposed to the thermocouple and I clean after every roast.  By the phenum I assume you mean the smoke box assembly or collar area near the thermocouple.. It's pretty gross..  Previous owner never cleaned it.   

This? 

[Joe]

yep that. Clean it with a damp rag and be sure not to touch the thermocouple with anything wet.

The MCU is internal and it controls the ignition, usually it is a misfire that causes the code to post and it's about a $175 part. I had some E3 or E2 codes that was caused by the MCU, the sonofresco techs can tell you how to diagnose it.

[Burner0000]

Ripped it apart and cleaned it last night.  I don't think the previous owner ever cleaned it.. It was thick! Turned the J cloth brown.  Look's new now.  I'm gonna turn the valve screw up tonight or tomorrow night and do a test roast.

[sgreen]

For future reference, the attachment is a pdf detailing Nat gas/Propane conversion for a couple of different gas valves. Sonofresco uses the Robertshaw 722 Uni valve in fig.5 on page 3.

FYI: on a natural gas machine, you'll have to do a nearly complete disassembly to swap out the natural gas burner orifice for a number 51 propane orifice. This can be ordered from Sonofresco for about $20 or bought anywhere else for about $15. Like most of what's inside a Sonofresco, it's a standard part.

For the regulator, you'll need a RobertShaw 722 conversion kit. About $10 on Ebay. This will be a replacement regulator spring (see the attachment) and a plastic set screw. To install the spring and/or adjust the gas valve regulator, you'll get at the valve through a small hole in the bottom of the machine. Use a flat blade screwdriver to remove the aluminum cap and then the same screwdriver to increase (clockwise) or decrease (counterclockwise) the gas pressure from the valve.

I had to figure this out by trial and error. Smarter guys, -everyone else- will just watch the videos on YouTube before, instead of after, making the adjustment. 

[Burner0000]

For future reference, the attachment is a pdf detailing Nat gas/Propane conversion for a couple of different gas valves. Sonofresco uses the Robertshaw 722 Uni valve in fig.5 on page 3.

FYI: on a natural gas machine, you'll have to do a nearly complete disassembly to swap out the natural gas burner orifice for a number 51 propane orifice. This can be ordered from Sonofresco for about $20 or bought anywhere else for about $15. Like most of what's inside a Sonofresco, it's a standard part.

For the regulator, you'll need a RobertShaw 722 conversion kit. About $10 on Ebay. This will be a replacement regulator spring (see the attachment) and a plastic set screw. To install the spring and/or adjust the gas valve regulator, you'll get at the valve through a small hole in the bottom of the machine. Use a flat blade screwdriver to remove the aluminum cap and then the same screwdriver to increase (clockwise) or decrease (counterclockwise) the gas pressure from the valve.

I had to figure this out by trial and error. Smarter guys, -everyone else- will just watch the videos on YouTube before, instead of after, making the adjustment. 

Thx!  I have already ordered and converted the machine from Propane to Natural Gas.  I didn't notice that there was a hole in the base of the roaster to make the adjustment.  That will make things easier.

BTW: would anybody know the thread size on all the hex screws under the machine?  Previous owner stripped the crap out of them..