Coffee Roasting Anyone here do static airflow?
@raccroasters
Posted in Coffee Roasting
Anyone here do static airflow?
I was talking with Rob Hoos the other day and we started discussing roasting strategies and preferences and one of the things he does is roast with static (and high, 100% on his machine) airflow. He just published a booklet on experiments regarding airflow for those interested you can find it in his website.
I think most of us follow a low-med-high airflow progression during roast, I recall a Derek de la Paz video on roasting a Pacamara using Static Airflow but it isn't too widespread.
Also part of our conversations, and to be honest I haven't actually tested this myself, is that I think that MCR machines have very powerful fans. Like if I were to bump my airflow to 100% I've always figured, but never tested, that I'd just be sucking beans out of the drum and diluting down the heat with, relatively, cold air coming from the room. FWIW, and I know this is extremely configuration dependent, currently using 26 Hz as low, 30 Hz as Medium and 34 Hz as high on my setup.
Thoughts on this?
Very interested in seeing if anyone else has done this. I was just reading Robs lighter method review where he goes over some of this. I also just ordered his field notes book, so I am looking forward to that.
https://hoos.coffee/blog/the-lighter-method
@Slimfl08 said:
Very interested in seeing if anyone else has done this. I was just reading Robs lighter method review where he goes over some of this. I also just ordered his field notes book, so I am looking forward to that.
https://hoos.coffee/blog/the-lighter-method
You should join the mentorship group, we have weekly office hours with Rob and a monthly meetup. Only a couple of people generally join office hours so it's like almost one-on-one consulting for $40 a month
I will have to check that out. I actually juts reached out to Scott Rao in regard to one of his sessions so I can try to figure out where I am getting stuck. Thanks for the additional input! When are the office hours?
Consultants frequently recommend static airflow to eliminate a variable and simplify machine control for their noob clients.
Too, a lot of roasters are built with much less less precise and less repeatable airflow control than is found on our roasters.
We realized that VFD control over airflow was good, but not always consistent because of vent and fan fouling.
In other words, at any given Hz, when the fan or venting or vent cap is crudded up, you are moving less CFM.
BTW, that's the reason the fans are overpowered. They'll allow you to move enough roast air even when you are overdue for maintenance.
If you are on a MCR roaster with a digital drum pressure gauge, you are measuring 1/248 of 1" of water column. That's not just window dressing. It delivers the kind of precision allows you to dial in an optimal conductive to convective heating ratio for every roast.
You can go static airflow if you want. It will simplify the operation of your roasts, but it will do it at the expense of both cup quality and the development of your craft.
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