Yesterday I roasted nearly four pounds of coffee… in three ounce batches. Today I attacked my Hearthware Gourmet with a spoon [and a drill, and some electrical supply bits]. It’s now a 6 oz. roaster.
I’ll put a picture essay up on Bloggle sometime soon [though very likely after the holidays] but here’s the low-budget version…
It’s pretty clear that air flow is constricted on the Gourmet — there’s plenty of oomph generated by its built-in blower, but there’s very limited inflow and outflow where the roast chamber itself is concerned. I made three modifications…
1) I enlarged the outflow of the base unit… the “air-scoop” type vents. By using a sturdy spoon I was able to retain the same general shape: flat on the surface, rounded below, so as not to overly muck with the general airflow properties. [I figure the vents are shaped as they are with reason… and I don’t have any particular cause to question it right now]. I enlarged the vents, best I can tell, between 1 and 2 millimeters, leaving plenty of room, still, between the lower portion of these vents and the heating element, below.
2) I enlarged the inflow of the roasting globe. An operation very similar to the base unit, I again employed my trusty spoon to increase the size of only the *larger* vents, taking some care to leave the shape of the opening pretty much intact. Once again, I modified these vents by 1 or 2 millimeters… they are still small enough that I don’t expect any coffee beans would fall through the cracks.
3) I drilled out the “lid” of the chaff collector… I removed the knob and plastic medallion on the lid, and drilled a pattern of small holes in the area of the lid that the medallion formerly covered. I made a trip to the hardware store and picked up some aluminum window screen fabric, and a round, galvanized steel fitting, used as an extender for household wiring boxes. I drilled two more holes in the lid to match the holes in the electrical fitting, and sandwiched screening between the two.
The results — very even roasts. Surprisingly so. The beans in the center of the chamber begin a wee bit less roasted then their compatriots [you can note a difference in color] but as first crack nears the difference is negligible, and near second everything is fully integrated and happy. Importantly: no tipping, and no scorching.
The air-scoop enlarging and lid drilling was matched with a number of test runs… tweak a bit, load in some beans and check airflow… tweak some more, load more beans, etc. With this setup I can do 6 oz. green at *room temperature*. A test run outside demonstrated that these mods cannot compete with the heating requirements of 40 degree temperatures. However — and this is the sweet part — if I simply add the plastic medallion to the top of the lid [thus covering my grid of extra outflow holes and restricting airflow] I have essentially a stock roaster, and I *can* roast outside, albeit with a normal 3 oz. batch.
I expect I’ll tweak the chaff collection further [I’m thinking of dispensing with “collection” devices altogether, and instead building a deflector that shunts chaff into the kitchen sink, which I can fill with water to “catch” the chaff as it blows off. But that’s another day.]
I don’t see any real downside [other than the obvious warranty voidance bit] and I expect this is just a precursor to mounting an external blower with variable temperature and air control… I expect this roast globe is good for better than 8 oz. of beans.
P.S. Hey, this is just what *I* did, and I don’t recommend you do anything remotely like this. You could put yer eye out, kid!