Another airhead drums: Initial Impressions of the Quest M3 - Page 34

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
User avatar
Carneiro
Posts: 1153
Joined: 15 years ago

#331: Post by Carneiro »

I've been thinking about making a mod similar to Rafael's (hot air input mod), but adding hot air from the back of the roaster.

One problem is that maybe heating the input air could penalize the heaters, that counts on cold air. Maybe the input could be done inside the drum (yes, it would require to drill a hole...), to make something similar to what Rafael did, but using the flow of the roaster to suck hot air inside the drum...

Any thoughts about it?

Márcio.

User avatar
Arpi
Posts: 1124
Joined: 15 years ago

#332: Post by Arpi »

you need very hot air (much hotter than the temp inside the drum). I use ~750F with slow airflow using a heat gun. Diverted hot air from the roaster is not enough (you'll be lucky if you get over 200F). The Brazilian beans come out outstanding (liquorish, chocolaty in espresso) . The very fast profile from dry to 1C makes all the difference (without the defects of a very hot drum surface). I use two cups of green beans.

Cheers

User avatar
Carneiro
Posts: 1153
Joined: 15 years ago

#333: Post by Carneiro »

Yes, I was thinking about a used air heater from Leister.

Two cups = 300g?

Márcio.

User avatar
Arpi
Posts: 1124
Joined: 15 years ago

#334: Post by Arpi »

Hi.

It will be a little less than 300 grams because the density of the beans is not very high. But for other beans two cups equal 300 grams.

This heat gun thing works best for Brazilian beans. I do about 4 mins dry, 4 mins to 1C, and 4 mins finish (total ~12 mins). The chocolaty flavor comes from the degree of the roast (1 minute past first pops of second crack). The liquorish flavor comes from the high speed to 1C and the residual humidity. As soon as I hear a first pop, I lower the heat gun airflow (every thing else stays the same) to the minimum. Then I wait till pass second crack first pops (~ 4 minutes for espresso from 1C first pop).

Cheers

User avatar
Carneiro
Posts: 1153
Joined: 15 years ago

#335: Post by Carneiro »

That's why I'm interested in this mod, considering I only roast Brazilian beans!

But in general I don't reach second crack, I don't like the bitter flavors from the roast. But maybe that could be something I would not get so strong using the hot air...

Maybe I could test a heat gun I have at work before try other thing. But it's a simple one, without the digital control.

Márcio.

User avatar
Arpi
Posts: 1124
Joined: 15 years ago

#336: Post by Arpi »

If the heat gun has a setting for low airflow then it will be OK.

Cheers

User avatar
Carneiro
Posts: 1153
Joined: 15 years ago

#337: Post by Carneiro »

The heat gun I see around has the lowest air flow around 250 L/min, do you know how much is yours?

Márcio.

User avatar
Arpi
Posts: 1124
Joined: 15 years ago

#338: Post by Arpi »

I am not sure of how much airflow. The heat gun I am using has 10 airflow settings. I use #2 (second lowest) for high speed ramp to 1C and #1 (lowest) for a slow finish. On top of that, I also use a heat gun tip reducer (that fits inside the trier hole) which brings down the airflow more.

For more information see this thread:

Heatgun upgrade for Quest M3 roaster

Cheers

User avatar
Carneiro
Posts: 1153
Joined: 15 years ago

#339: Post by Carneiro »

Always nice to remember! Looking for your heat gun model I found the specifications.

So, probably the steps add 34 L/min, and you use something like 150 L/min (#2) and later 113 L/min (#1).

I think the two heat gun I have at work has minimum 250 L/min air flow, but I could try it anyway.

Márcio.

User avatar
Arpi
Posts: 1124
Joined: 15 years ago

#340: Post by Arpi »

Good find.

You could always bring down the airflow by adding a restriction (like making the hole smaller).

Cheers