I really enjoyed roasting on a Popcorn Popper back in November, and I'm sure it's more rewarding for brewed coffee.. but as an Espresso lover.. less than 1/4 of a pound simply wasn't acceptable, despite the awesome results. Recently, I was browsing Sweet Maria's and quickly got drawn into looking at how reasonably priced greens where. Before I go crazy and start buying a lot of beans, I want to know what methods you guys use to roast larger batches of coffee at home? I have a bread maker lying around, and I've thought about that, but I wanted to exhaust all possibilities. For the actual roaster I have a budget of about $100 to get something functional.

I found I could easily roast 250g batches in a heat gun / bread machine setup with good control over the profile. A full pound would have resulted in a very slow profile, which I don't recommend.

If you really wanted to do a full pound using an inexpensive home-made setup, my best bet as to what would work would be a gas-grill + rotating drum design. Look around on homeroasters.org and I bet you can find some good inspiration for how to build something along those lines.

I'd probably be roasting Brazil's, probably along the full city line.. if that makes a huge difference. I've heard of people roasting 1.5lbs in HG/BM roasters.. I wonder if modifying the stir cycle would make a difference. Maybe I should just try it and see what happens. Is there any specific heat gun someone could recommend just for this purpose?

I use the Zippy popcorn popper and do about 13 oz per batch. Takes anywhere from 11 to 13 minutes to finish a roast to the end of first crack. I've tried a full pound and wasn't happy with the results, but I didn't really make a strong effort to see if it was possible. Total price for the popper is 79 .99 and it's a much better built than the more commonly found whirly pop.

I thought this was a scalable idea.

Making Your Own 57 Ounce Roaster [Updated Again]

Adjust the size of the milk can to fit with your intended capacity.

I bought an asparagus steamer at a thrift store to make into the drum. I bought a gearhead motor from an eBay vendor to turn the drum.
I had planned to use plumbing fittings to attach the drum to the shaft and so on. Pretty simple.
I never made it because a used Quest caught my eye.

Oakeshott wrote:I use the Zippy popcorn popper and do about 13 oz per batch. Takes anywhere from 11 to 13 minutes to finish a roast to the end of first crack. I've tried a full pound and wasn't happy with the results, but I didn't really make a strong effort to see if it was possible. Total price for the popper is 79 .99 and it's a much better built than the more commonly found whirly pop.

I actually have a Whirly Pop that I use for making pop corn, I never used it to roast coffee because I heard how uneven it could be. Other than build quality what's the difference?

I used to use a Whirley Pop in the past for full pound roasts. I didn't find the roasts uneven at all and actually produced some great results.

EvanOz85 wrote:I used to used a Whirley Pop in the past for full pound roasts. I didn't find the roasts uneven at all and actually produced some great results.

Hmm I'll give it a try after giving the Whirly Pop a good clean. Would using an induction top cause a problem? That's all I have access to.

I dunno about other roasters, but for air roaster you will need closer to $250 and at least a 20 amp and/or 220v circuit,

2000w heating element - $35 (heat gun or kiln)
6 to 8 Amp Shop Vac - $50 (for blower)
Speed controller - $35 (to control blower)
Bake a round - $20 (for roasting chamber, need to verify bake a round big enough for 1lb, if not add $20)
PID setup - $40 (to control heating element)
Thermometer - $10 (for bean temp)
Case and Misc - $40 to $60

You can do a half pounder for...half the price, and only need 15-amp circuit, (dedicated and nothing else running on it while roasting)

Popper - $20 (poplite for large batches, NOT poppery)
Lamp Chimney - $6 (get from Michaels to extend roasting chamber)
4-Amp Shop Vac - $30
Speed controller - $20
PID setup - $40
Rubber fitting - $5 (to connect shop vac to popper)
Thermometer - $10

You may be able to get away with a 4 to 5 amp blower on the 1 pounder, but can't vouch for that.

The biggest difference between the whirly pop and the zippy is the metal used. The whirly pop is aluminum and the zippy is stainless steel. The thermal conductivity of aluminum is quite high which contrasts with unusually low thermal conductivity for stainless. In other words, the two metals handle heat completely differently from one another. The stainless popper will hold the heat while the aluminum tends to wick it away from the source. My feeling, unsubstantiated by experience with the whirly pop, is that it would be harder to avoid hot spots and scorching with the aluminum because you'd need a higher flame in order to get the same heat in aluminum. From my earliest roasts in cast iron, a low thermal conductivity material, I saw a correlation between flame size on the gas stove and degree of scorching. As I said, however, I've not used the whirly pop and so could be wrong on this point.

There are other differences as well. The top on the zippy is fully removable which makes cleaning simpler and also gives one the option of using a whisk as opposed to the turn handle. It also allows for better venting of smoke/moisture than the whirly pop. The thicker metal also gives it a more substantial feel.

My only complaint is that the height of the fins that do the stirring are not adjustable. They're about an 1/8 of an inch too high for my taste. It means that one can't really do less than about 12/13 ozs of beans without diminished agitation from the stirrers and even at optimum fill, there's a spot right in the very center where about a dozen or so beans don't get adequately stirred. I'm cogitating on ways to fix this.