Arpi wrote:The problem is not that the Q3 is weak. A more powerful heater would not do anything . If you use more power, the drum heats too much and the beans scorch (too high drum temperature).

What about a more powerful blower fan to improve air circulation?
Roy

rmongiovi wrote:What about a more powerful blower fan to improve air circulation?
Roy

There is only so much hot air you can get that way with the the type of heaters used. I think it works well heating the drum separate from the air like mixing two types of roasters.

When the exterior surface of the drum is stable at 540F (safe temp for all beans), the color of the heaters is barely lit (like dying charcoal). That means that the temp of the heaters is much colder than when bright orange/yellow (full power). Having the heat of the drum independent of the air is a good way to guarantee that the surface of the drum stays within the safe cold zone. Providing independent hot air simplifies things. And providing a single heater for both purposes makes things complicated. Again, the Q3 works well out of the self . This is an enhancement not a fix. And there is no need to mod anything inside the Q3.

I think that in general, drum roasters provide a more "toasty" flavor (from the contact of hot surface of the metal drum), meanwhile air roasters provide a more "boil" flavor (maybe that's not the right word, clean flavor?). Air roasters roast faster but with a different flavor.

Cheers

Very elegant addition!

I think the commercial roaster manufacturers are significantly limited by liability, and won't ever build a roaster for home use that we thoroughly enjoy. As an example, the modification you added would be 'easy' for 'them' to incorporate, but then someone would run 24amps through a 18ga extension cord and burn their house down.

I love modifications, but I don't write insurance policies either. (I'm not knocking, because I roast with a home-made nuclear reactor that couldn't get UL listed on the black market.)


CHAD

Arpi wrote:I think that in general, drum roasters provide a more "toasty" flavor (from the contact of hot surface of the metal drum), meanwhile air roasters provide a more "boil" flavor (maybe that's not the right word, clean flavor?). Air roasters roast faster but with a different flavor.

That's exactly why I'm looking for alternatives to this mod. I'm interested in the M3 exactly because it's a drum roaster and not a hot air roaster. Tom's (at Sweet Marias) comment about batch size made me lose interest since I really want a roaster that can handle 1/2 pound with ease. His comment that batch size should be 120g is most disappointing. But hanging a heat gun off of the sample port wouldn't be a fix I'm looking for....
Roy

Roy.

Always do what makes you happy. The 120 grams batches probably produce the best results but that does not mean that the roaster cannot be used with higher weights. 200-240 grams are also good but not as good depending on who is judging. Maybe 300 grams are good for some people. It is not something black or white. What is written in buying literature from roaster manufacturers may not be a match to what is best. For example, I may be wrong here, but I think other roasters with smaller drums are "rated" with higher batch weights than the Q3. Something to think about.

Cheers

A roaster like the Behmor, rated by the manufacturers at one pound, does this load in about 25 minutes; and people once praised the Hottop for doing 300 grams in around 20 minutes. But this type of specification is BS -- once roasts go longer than about 15 minutes, the probability of them sucking goes up dramatically.

The Quest people are the first to give honest load specifications, probably because they are also marketing to professionals, who know the difference between baking and roasting coffee. To get a 15 minute production roast on a stock M3, you need to confine yourself to around 200 grams; to get a sample roast time of around 10 minutes, you need to go down to around 120 grams.

As you've seen from Rafael's posts, the roaster is well suited for modifications that permit higher loads. I prefer doing 100 to 200 grams loads, so I haven't done anything except add insulation. But my guess is is that you can load the drum to about 350 grams without mechanical problems, and that there are several good approaches to getting properly fast roasts at this capacity.

The airflow has to be considered in relation to the heat. As is, the airflow and heat are balanced -- if you run the heat flat out and the air flat out, you'll get the outer drum up to around 270C/510F. Unless you add insulation, increasing the airflow will do nothing but cool off the beans and slow down the roast.

Instead of a heat gun, the mod I'm considering is a second case for the roaster which encloses the exhaust tube and the drum itself. The air inside the enclosed space will get quite hot, and if the intake air is drawn from there, it would work like a Franklin stove, recovering some of the heat. A mod like this would permit the installation of a more powerful fan, and allow for either faster, albeit "airier" roasts, or for higher loads.

It has been posted several times here on HB that for the "best" results one needs to reduce the batch size to 200g or below. Regardless of who has posted or written about this, I don't personally accept this as settled truth. My own experience is that I have successfully roasted 227g (8oz) a number of times, with roast parameters and results that I do not believe would be improved with a lower batch size. I would have to see some objective proof including blind tasting results before I would accept that one must charge the roaster with less than this for the best results.

This having been said, I think that Rafael's heat gun mod post presents an intriguing idea, and might be the easiest way to increase the batch size with good results, as long as one used a separate electrical circuit for the heat gun. One can pontificate from here to the moon about how this would effect the "air flow" or "circulation," but in all honesty I couldn't give a rat's ass about that stuff; what I'm concerned about are end results in the beans and in the cup. And I don't think that any of us here know enough about the effects of something like an added heat source (and its ventilation) in the M3, like with a heat gun, and how it would effect the roast product, to comment on it (other than Rafael who has actually tried this mod.)

It would certainly be "cleaner" to change out the heating elements to something beefier that could apply more heat than those elements that are installed, assuming that those elements exist in the right form factor and that they could work on a domestic 20A 110v service, without damaging or tripping up any of the other electrical stuff installed in the roaster. A more powerful fan might be of use in addition, assuming one exists in a proper form factor that would fit.

And one needs to consider that when one roasts more beans in a batch, that more chaff is created and that this could result in a fire hazard unless the chaff is cleaned out more often than one would do so with smaller batches.

In the end, I think that Rafael's mod is probably the easiest and most cost effective way to increase batch size and/or speed up the roasts in an M3. Whether doing doing this mod will produce equally good results as the roaster produces with standard sized batches unmodified, I do not know. But it would be easily testable and looks like something with promise to me.

ken