Sonofresco / Q&A / Tip & Tricks

[rfeuker]

just fyi, sonofresco roasters use a 2 wire 1000 ohm platinum rtd.

I've never used RTDs; why would you use one instead of a thermocouple? And why are all the RTDs I see at http://omega.com 3-wire?

snipped
As far as an omega rtd that works with the sonofresco, I know that the RTD-870-1000 OHMS will work, as I modded my sonofresco 1 lb model to use that probe. (drilled a small hole for the probe in the exhaust tube and plugged up the other hole with metal duct tape)

Dang, I looked all over Omega and I didn't see those. Thanks for your help - I've been wanting to keep spares on hand, but the Sono replacements were too expensive. Plus the ones you found have stainless sheaths, so will be easier to keep clean.

I just ordered two.

I would also love to have a spare on hand and love the stainless steel sheath idea.  I get real nervous every time I clean mine.  Pardon the stupid question but is the connector on those Omegas the same as on the Sono?  Just wondering if I might have to do some "doctoring".

[hootowlcoffee]

Ok so I have been roasting and keeping tabs with my roastmaster app for over a year now on my sf 2#.  I roasted a blend that I have done hundreds, if not thousands of times before.  It cupped 32 hrs later and did well, just like it is suppose to.  I placed a 1/4# in a valve bag, like usual, for home consumption.  I get it home, brew in aeropress and it tastes metallic and bitter.  So i brewed as a french press and I got the same outcome.  Reminds me of if you have ever had the char oils off of wood and accidentally tasted it, like the black smoke residue off the sides of a grill.  Makes your face go funny as your tongue catches up with what just happened.   Not sure what happened, but it roasted IDENTICAL to every one before hand, along with 2 roasts after that which tasted fine.  Not sure what happened, your thoughts?

[Tex]

Ok so I have been roasting and keeping tabs with my roastmaster app for over a year now on my sf 2#.  I roasted a blend that I have done hundreds, if not thousands of times before.  It cupped 32 hrs later and did well, just like it is suppose to.  I placed a 1/4# in a valve bag, like usual, for home consumption.  I get it home, brew in aeropress and it tastes metallic and bitter.  So i brewed as a french press and I got the same outcome.  Reminds me of if you have ever had the char oils off of wood and accidentally tasted it, like the black smoke residue off the sides of a grill.  Makes your face go funny as your tongue catches up with what just happened.   Not sure what happened, but it roasted IDENTICAL to every one before hand, along with 2 roasts after that which tasted fine.  Not sure what happened, your thoughts?

I almost hate to ask - but was the bag new? Did you grind it just before use and does your home grinder need cleaning? It sounds like it's extremely stale from the way you describe the acridity of it.

If all else fails, recup it to see if you get the same impressions that you did at 32 hours.

[hootowlcoffee]

The bag was not just opened and the grinder is clean.  I am roasting tomorrow and will test some ideas. 

[Tex]

Some of you have asked about how & where I place thermocouples in my Sonofresco roast chamber. I've put together a PDF of images to better illustrate how I do it.

Questions/suggestion?

[ScareYourPassenger]

I run mine the same way but don't have a logger. Have you noticed different chamber temps with the colder outside air?

[Tex]

I run mine the same way but don't have a logger. Have you noticed different chamber temps with the colder outside air?

Hah, it was down to 64°F here today. If it's cold enough to need a jacket I'll just wait a few days to roast.

I don't bother logging my roasts; just monitoring the bean temp is enough.
 

[jittery_java]

just fyi, sonofresco roasters use a 2 wire 1000 ohm platinum rtd.

I've never used RTDs; why would you use one instead of a thermocouple? And why are all the RTDs I see at http://omega.com 3-wire?

snipped
As far as an omega rtd that works with the sonofresco, I know that the RTD-870-1000 OHMS will work, as I modded my sonofresco 1 lb model to use that probe. (drilled a small hole for the probe in the exhaust tube and plugged up the other hole with metal duct tape)

Dang, I looked all over Omega and I didn't see those. Thanks for your help - I've been wanting to keep spares on hand, but the Sono replacements were too expensive. Plus the ones you found have stainless sheaths, so will be easier to keep clean.

I just ordered two.

I would also love to have a spare on hand and love the stainless steel sheath idea.  I get real nervous every time I clean mine.  Pardon the stupid question but is the connector on those Omegas the same as on the Sono?  Just wondering if I might have to do some "doctoring".

Nope, long wires. You'll need to cut them to approx. the same length as the sono temp sensors and connect them to your old connector plug.
I had a few old temp sensors laying around so I pulled off one of their connectors and silver soldered (you could use lead-free, but it's a pain to work with) my new temp sensor in. If you don't know how to solder, you could try to find new pins and crimp them on. The only drawback to the metal sheaths is temperature coupling. Sometimes when I do roasts back to back I get an error 2 right at the start. Power cycling fixes it, and the stainless sheaths are so easy to clean (and much more durable) I don't mind. (it sure beats the error 1 3/4 of the way through the cycle that the sono temp sensors started doing every 3 months) I do approx. 40-50 lbs. a week through my 1 pounder, and i've been using one of those stainless sensors for the past 16 months.

P.S.  it is 27°F here tonight. I've roasted when its - 30, and it doesn't seem to take longer after the first roast.

[ScareYourPassenger]

Got my tc4 logger up and running. I am adjusting the gas valve and recording the results.

Current assumption that the colder weather was battling the valve adjustments I made might be correct.

[ScareYourPassenger]

The cupping confirms it. The trial 1 roast is a clear winner with proper development and won't bake the beans by extending 1st crack too long. I highly suggest dialing in the sono for outside air temp. Next trial is to see how working by volume a weight affects the roast. Dip prior or just after first crack?

[hootowlcoffee]

Is this adjustment going to keep my dp Ethiopian coffees from running away while i try to gamble with the gas off button.  It's like trying to hit a rabbit with a pellet gun at 100yards.  Has anyone found a solution to the insane amount of chaff build up and your roast ramping way to fast 30sec into 1st.   

[ScareYourPassenger]

Is this adjustment going to keep my dp Ethiopian coffees from running away while i try to gamble with the gas off button.  It's like trying to hit a rabbit with a pellet gun at 100yards.  Has anyone found a solution to the insane amount of chaff build up and your roast ramping way to fast 30sec into 1st.

It might, if you look at the trials I increased it by the same amount each time and the ramp increased. The chaff has not been as issue for me and I have had some very chaffy? roasts.

I would check the top probe and make sure the sono temp sensor is working properly before adjusting anything. I did this by putting another probe next to it and checking the readout of the sono vs the other temp sensor.

[ScareYourPassenger]

More logging in colder damper weather. I had to adjust the valve again to keep up with the outside weather.

The sono may be dead simple to use but I am getting irritated with it either ramping too slow or too fast due to outside conditions.

[hootowlcoffee]

More logging in colder damper weather. I had to adjust the valve again to keep up with the outside weather.

The sono may be dead simple to use but I am getting irritated with it either ramping too slow or too fast due to outside conditions.

I am wondering if this same experiment done reverse would slow down my roasts during the summer months.  I rent a warehouse and it gets around 75 during the summer which raises the ambient temp of my beans.  I am noticing on my nights I roast, my first 1-2 roasts are 1 minute ahead of schedule and then the 3-4 are 30 seconds and the rest fall 15 seconds faster than normal during the cooler months.  Am I missing something or can your crazy theory work for me?  If so, what do I do, and what do you suggest?  I have a 2lb Sono.

[ScareYourPassenger]

This should work for you as well. The logging was the proof that it worked and my roasts have improved because of the adjustments.