Replies to This Discussion

Permalink Reply by greg costello on December 28, 2009 at 9:18am

any change in roast times? (slower?) interesting topic though sorry no immediate definite reasons

Permalink Reply by Bryan Dyer on December 28, 2009 at 9:33am

Different varietals, processing methods, and even different lots of the same varietal can produce different amounts of chaff.
Have you tracked this?

Permalink Reply by Rebekah on December 28, 2009 at 6:40pm

Our roast times are fine. The decrease has happened pretty abruptly and evenly across the board for all the coffees, so I think it's more than a matter of varietal differences. Jamie, what you say could very well be the case. We recently replaced the hood on our stack, and though it was the no-loss stackhead most recommended for proper ventilation (see "Stack Overflow" in Sep/Oct. issue of Roast magazine), it still lets in the elements (maybe not rain as much but definitely the snow). I guess for now we'll be making sure our stack gets cleaned out and checked regularly.
--This might not be related, but I also remember the change happening simultaneously with an increased difficulty in hearing first crack for several of our coffees which we use regularly (mainly Brazil YB but also others--Indonesian, etc.) The sound was more muffled and every now and then I couldn't hear it at all.--

Permalink Reply by greg costello on January 4, 2010 at 3:54pm

less chaff, difficulty hearing first crack. This is exactly what I was getting at in first question. 'If times are longer gases escape in more controlled way. crack gets disipated as bean expansion is not as violent. This inturn means the bean doesnt quite expand as much alot of chaf wont get free of bean.

Now if you come back and say roast times havent moved out.....well I will be intrigued.

Permalink Reply by Rebekah on January 4, 2010 at 5:44pm

the times have not become longer...and first crack usually happens around 9 min for most of the coffees.

Permalink Reply by Andrew Phillips on January 7, 2010 at 10:47pm

Any changes to your airflow system? Blower motor/impeller fan blade? There's the possibility that you're shooting the chaff out like you said or, conversely, the chaff is staying in the roast. Sounds like the ducting or something along the way is getting dirty and you're having a restricted airflow. Perhaps the cold makes things constrict in a way that kinks up your system?? I liked Jamie's idea of installing "quick peek" hatches at key points in your ducting-especially where it makes an elbow (I hate elbows!)...

Permalink Reply by Rebekah on January 8, 2010 at 7:23am

Yes, I like the "quick-peek" idea as well, and we're figuring it's definitely got to be the ductwork and winter clumping. Oddly enough, the past week or so we've suddenly had normal amounts of dry chaff come out! It made for a good discussion:) but we'll defiinitely still be making sure the ductwork is clean.

Andrew Phillips said:

Any changes to your airflow system? Blower motor/impeller fan blade? There's the possibility that you're shooting the chaff out like you said or, conversely, the chaff is staying in the roast. Sounds like the ducting or something along the way is getting dirty and you're having a restricted airflow. Perhaps the cold makes things constrict in a way that kinks up your system?? I liked Jamie's idea of installing "quick peek" hatches at key points in your ducting-especially where it makes an elbow (I hate elbows!)...