I am curious about how the fan works on the Quest. Can owners share their experiences with how they use the fan and how it affects ET? What kind of convection power does the M3 have? Can the fan be maxed without adversely affecting ET?

Thanks,
~j

Hi.

In my experience, the incoming air is cold and affects negatively the speed of the roast (slows down the total time). To get the shortest roast time, you would adjust the fan to barely move the air through the roaster. There are also tricks that could be done, like preheating the intake air.

Cheers

I disagree. It is like any other convection process. If you keep the drum temperature the same, going from low to high airflow speeds up the roast. Anything else is not physics, but magic.

I basically keep my drum temperatures fairly constant between 450F to 525F throughout the roast (exact temperature depending on bean and profile), and slightly regulate the roast speed by altering airflow. Raising airflow speeds the roast, but requires a simultaneous increase in the heat to keep the drum temperatures constant. The fan on the M3 is not powerful, so the effect is that a max airflow roast of 150 grams is about 2 minutes faster from drop in to first crack than a min airflow roast (fan just barely turning, around 3 - 3.5)

Hi Jim.

I see your point. To me, the trick is in the temperature of the air, and how-much & how-fast the heaters can heat up the air. Convection can be used either way. It can heat the beans and it can also cool the the beans depending on the air temperature. I remember from when I had a FreshRoast Plus 8 (convection roaster) that too many beans shortened the roast time as the air passage was blocked. And too much air lengthened the roast time.

Cheers

The Toper Cafemino has no control over gas pressure and uses air to control ET where the Diedrich IR's bring air over heat syncs to pre-heat it before entering the roast chamber so it is difficult to lower the ET with airflow.

My observation is that, the fan / airflow in M3 will definitely lower the measured "MET" but helping the heat transfer evenly to the drum, hence raise the temperature of both the BT and ET a bit in normal circumstance (not in extremely cold air intake)

You can always add a heat gun je je. That will give you unlimited power in terms of convection. For example, I just did a roast to demonstrate the power (see mid phase):

Beans: CR Herbazu beans
Weight: 255 grams



Note: the HG messes the BT temp a little.

The beans did not taste burnt to a chewing test after the roast. Set the Heat gun to 800-900F at HG_fan#3 during mid phase. Then at finish phase (after First Crack) I set the HG_fan#1. The Q3 fan does not matter here much but I had it at #7. I used a medium sized air nozzle (fits the Q3 perfect). Usually, I use the smallest nozzle (less heating power and also fits the Q3). This power flexibility allows me to explore the profile spectrum regions

Cheers

I might have reservation on using heat gun on M3, would the air-roast (convection) effect dominate the drum roast (conduction) effect .

Hi.

In my case, the airflow and its temperature are controlled by knobs. I can always turn them down. It is an extra option, not a full time modification. I think in some cases, a convection roast is better, for example like when doing soft beans. A Drum roast adds something similar to a "bark" in the contact points. The outer surface of the bean gets more done (like if roasting in a grill), which may add a positive complexity when not overdone.

I am trying now the coffee and I did not get a "toasty" flavor. I was expecting that. Probably that happens when using a fast ramp in drum roasters (very hot drum- very hot grill). It is a little bright. Some beans started the second crack and it has minor visible unevenness, but it does not taste bad. No "toasty" defect here.

Cheers