Drum Roasters - when do you change air; your theory?

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
User avatar
CarefreeBuzzBuzz
Supporter

#1: Post by CarefreeBuzzBuzz »

MCR roasters recommends low to DE, medium until FC and then high in their starter manual.

I thought that was too many changes so I found my max convection setting and backed off that a small amount and left it until 45 seconds after FC where I up to where I think it will blow out smoke and chaff but won't impact ROR. I am not always right especially with beans I don't know too well so I do make other adjustments if I think they are warranted.

What do you do and what's your theory?
CarefreeBuzzBuzz
___
Artisan Quick Start Guide
http://bit.ly/ArtisanQuickStart

mkane
Supporter ♡

#2: Post by mkane »

If I had a theory I may be able to solve my flick and crash issue that seem so prevalent lusting after a 20% 3rd phase. I can do it with an extremely high gas setting and just use air but that's a band-aid.

User avatar
Almico
Supporter ❤

#3: Post by Almico »

I use air to enhance convection and evacuate chaff and smoke. I do not use it to control how much heat, just the type of heat. I will sometimes use it at the end of a full city roast to mitigate a flick.

I adjust heat pretty much just as MCR suggests: 25% to DE, 50% to FC and 75% after FC. This seems to be working well.

User avatar
TomC
Team HB

#4: Post by TomC » replying to Almico »


Your coffee is phenomenal, so keep doing what you're doing.

I committed a cardinal sin by not jarring up and freezing the big bag of your espresso.

Marcelnl
Supporter ♡

#5: Post by Marcelnl »

My approach sounds similar to that of Almico, I try to adjust air in three stages but sometimes have to cheat a bit to overcome a flick. I did notice that bolder air adjustments sooner in the curve work better to keep things manageable than chasing the curve...
LMWDP #483

User avatar
CarefreeBuzzBuzz
Supporter

#6: Post by CarefreeBuzzBuzz »

Those doing three changes? Why?

Prior to DE - don't blow the heat out, you'll only fight it with more gas?
After DE - max convection?
After FC - blow chaff and smoke out?

Don't three changes in air mean even more changes in gas?
And more uncertainty every time you have a new bean. For those not buying large lots its only a few roasts to get it right.
CarefreeBuzzBuzz
___
Artisan Quick Start Guide
http://bit.ly/ArtisanQuickStart

User avatar
Almico
Supporter ❤

#7: Post by Almico »

TomC wrote: Your coffee is phenomenal, so keep doing what you're doing.

I committed a cardinal sin by not jarring up and freezing the big bag of your espresso.
That made my day, Tom! I'm so glad you like it. I value your opinion above most.

User avatar
hankua

#8: Post by hankua »

CarefreeBuzzBuzz wrote:Those doing three changes? Why?

Prior to DE - don't blow the heat out, you'll only fight it with more gas?
After DE - max convection?
After FC - blow chaff and smoke out?

Don't three changes in air mean even more changes in gas?
And more uncertainty every time you have a new bean. For those not buying large lots its only a few roasts to get it right.
That's for sure, roasting half of a 1lb bags from SM; although they do put a little extra in there :D

Prior to DE - I'm just following what people have done before me with the identical machine. Which is to close the damper all the way, still has an air flow; mine is .02"wc.

After DE - I increase the air flow to .05"wc, it was too low before and correlates to the previous (non-pressure gauge) used setting of 2-3 damper.

After FC - I'm presently leaving the damper alone or .05wc until around 55-60 seconds post 1st crack increase to .10"wc (after heat reductions). Need to evacuate chaff and smoke during this phase and prior to dump the air is increased to maximum usually runs .15"wc.

As far as theory, just speculating here; prior to DE a low air setting would give the beans a chance to heat evenly wheas a high convection model would cause the outside to heat quicker than inside.

After DE how much air (within reason) is going to control how fast the development phase runs prior to FC. Maybe it doesn't matter how much convection or maybe it does for uneven development? My other question is why use more airflow than's necessary to achieve the end goal? If the goal is to hit first crack in 7:00 that would be different than say 9-10 minutes onset of FC.

The advice of leaving the controls along just before and after FC seems practical. Usually I would step down the heat before increasing air flow before drop. That doesn't work if the goal is to hit second crack, and I'm been playing around with leaving the heat on high as long as possible and using the fan to control ROR before reducing heat.

User avatar
Brewzologist

#9: Post by Brewzologist »

Sorry, no theories to share. But, I ran tests in Artisan with an empty roaster at different gas settings with the goal of maintaining temperature equilibrium, and then changed fan settings (0,25,50,75,100%) to see when the effect went from conductive to convective to cooling for a given gas setting.

While just a proxy, based on these test results I generally start off with no/low fan thru TP, then increase to medium thru FC, and then increase again later in FC to max cooling effect to clear chaff/smoke and help avoid flick.

I experimented with increasing the fan at DE for more convection, but found it didn't really add much and I got better control using gas, so I stopped this to keep things simpler. Of course every roaster is different, but the airflow tests gave me a better sense for what is happening in my Huky during a roast.

User avatar
CarefreeBuzzBuzz
Supporter

#10: Post by CarefreeBuzzBuzz »

Brewzologist wrote:While just a proxy, based on these test results I generally start off with no/low fan thru TP, then increase to medium thru FC, and then increase again later in FC to max cooling effect to clear chaff/smoke and help avoid flick.
Thanks Steve, may give this a try. Lowering more till TP and then raising a bit more from where I have been through 45 sec post FC as I have.
CarefreeBuzzBuzz
___
Artisan Quick Start Guide
http://bit.ly/ArtisanQuickStart