Am using Harbor Freight router control for heat on split-wired poppery 1. I see most use dimmers to control fan. Just got great deal on another harbor freight router control. Any reason I shouldn't use this for fan control? By time I look at cost for dimmer, box, plug, on/off, and time to put it together, seems like easier and close to same price for me just to use two router controls, one for fan and one for heat. Any known issues/thoughts on doing this?

Second question. Need to buy 5-10 lbs of single designated bean (have been doing 'sample packs' and no consistency to my roast patterns) to learn consistent, repeatable profiles to get better at this. I know there are thousands of types out there, but any suggestions for a straight-forward, good-to-learn, forgiving bean that would serve this purpose? Have been happy with Sweet Marias, so one of their varieties preferred. Thanks for suggestions!

The router will work fine as a fan control. Use the fan control to start the fan at max, and to turn it down as the beans get light in the first crack. Aim for an even, unfrenzied level of agitation (although right at the start, it will be very lazy)

In terms of learning to roast -- a TC at the top of the chamber, where the air exits, will give you the bean temperature. A TX at the air inlet at the bottom will give you the environmental temperature. A good profile for the P1 is to start the the environmental temperature (at the chamber bottom) at 325F, and ramp it up over 8 minutes to 450F. Let the beans to do their thing until you reach the finishing temperature, then end the roast. On my P1, first crack started at 395, 2nd crack started at 435F-440F

These temperature figures will depend on the TC placement. The bean temperature at the top is fairly insensitive to placement, but the bottom one's readings can change a lot with slight differences in position. I wrapped my TC wire around the inlet grill and had the bar wire on the inside of the chamber, but still in the aluminum section.

A note on profiling with the P1: Trying to precsely regulate the bean temperature by letting the supply (aka environmental) temeprature cycle up and down will result in an inferior roast. The coupling between supply and bean temperatures is so tight on a small air roaster than you must be sure the supply temperature never drops, but rises steadily and holds constant at the end. Your best bet is to ramp up the supply temperature like I described, and to play with the ramp so you get roughly the the profile you want. This will taste better than getting the exact profile you want by going all jiggly on the supply temperature.

If you PID, either do it on the supply temp, or do it on the bean temp and detune the P, I , D constants by 50% so the control output to the heater, and the response in the supply temperature, is laid back and calm.

As far as beans go, you can look at it a couple ways, either get good coffee that is more forgiving or get crappy, hard to roast coffee. I recommend doing both, which is to say experimenting with cheap beans and then as you learn stuff, apply to better beans. I started with reasonably good coffee and arbitrary time profiles, e.g. 350 for first 4 minutes, 400 for the next 3 minutes, etc. and results were wildly inconsistent. So I bought these http://www.costco.com/Rainforest-Allian ... 54969.html and recommend them because, 1) They are cheap so I was less concerned with "ruining" them via experimentation, 2) the coffee was very unforgiving and really bland without proper development and I knew immediately if the roast was good or not, which IMO is extremely helpful to learning, and 3) the general concepts I learned translate perfectly well to other beans.

If you don't have access to costco, I would get 20lbs of something like these, http://www.happymugcoffee.com/green-off ... ferro.html If you do order from happy mug, I found 32lbs to be the sweet spot for shipping, so maybe get some Africans and Indonesians to contrast with the South American.

As far as roasting goes, I recommend reading this clearly brilliant and insightful post https://www.coffeegeek.com/forums/coffe ... 505#693505 Basic gist is I started out focusing on air temps and times and have shifted completely to focusing on bean temp, bean color, roast events (e.g. 1c), and learning to control roast development (1c to end of roast). I could roast perfectly well at this point without air temp readings or a clock. I would prefer to have a clock though I'm not expert though, so maybe better advice to follow.

another_Jim,

Thanks for thoughts, already have TC located about 1 1/4" up from bottom of popper, and pretty close to center of mass, so that has been working ok. Could you clarify 'TX at air inlet at bottom'? Do you mean slots at bottom of housing that allow air to come in, or vanes at bottom of chamber where heat is coming in to roast chamber? Currently, I have been using watts on Kill-a-watt to monitor power going router control then in to heater element. Did four small batches this weekend, where I start at around 850W, which gets me from ambient air temp (say 82) to 220F at about 1:20 from drop of beans, maintaining this wattage gets me to 300F at about 4:50 to 5:05 into roast, then I ramp up power to heater to about 1150-1200W, which gets me to FC at about 9:00 to 9:10 (at 397-400F), then go to bean temp of about 430 to 440F and pour out at around 11 to 12 min (this is based off of 4 roasts I did this weekend, at 110 g each type). Don't know enough about roasting yet to know if I am on track, and I have not developed the taste characteristics noted in threads here at H-B to know taste differences. Having fun trying, and don't really understand PID things yet, but will surely get there at some point, once I better understand things. Would like to find simple roast tracking software, as writing the temps, while attending to temp and power gets a bit 'busy'. Any thoughts on type of coffee to buy in bulk for learning consistent technique, or does it really matter? Earlier post has good suggestions to go w/Costco beans, which might make sense from cost perspective.

Your profile is about right, although you could try reducing your time to about 10 to 10.5 minutes, by knocking off 30 seconds at each part of the roast.

The supply air/environmental temperature sensor is at the bottom of the roast chamber, where the heated air enters the chamber through the slits, and is at its hottest. In an air roaster, you are looking ot keep it no higher then 475F, and preferably arounfd 450F, byt the end of the roast. Also, you want it climbiung steadily throughout the roast, not cycling.

Thanks Jim, I have a two input unit (from Thermoworks), so will try adding a second K unit as well. Your comment about PID got me searching on this site, but terminology gets way ahead of me (gave up at midgnight). Could you recommend basic info on H-B that would explain what I would need to capture the inputs of my two K units, record this, and be able to display/graph the outputs? Assume I need 1) K units in machine, 2) some way to get that into computer (have seen Omega units, Phidgets, usb connection, wireless) then software tracking/recording package (like artisan, roastmaster, etc). Do I have this generally correct? Looking for inexpensive way to start tracking all of this, and likely this has been been discussed for newbies before. Thanks for helping all of us newly initiated folks!

goducks wrote:Assume I need 1) K units in machine, 2) some way to get that into computer (have seen Omega units, Phidgets, usb connection, wireless) then software tracking/recording package (like artisan, roastmaster, etc). Do I have this generally correct? Looking for inexpensive way to start tracking all of this, and likely this has been been discussed for newbies before. Thanks for helping all of us newly initiated folks!

I have a meter that stores data and can transfer it via USB to a spreadsheet on my laptop. There are lots of ways of doing this cheaply, some of which you mention. I don't do hardware (you should see me try to solder even 12 gauge wire to know why), so I'm not up on the kits.

Thermoworks.com has a large line of different temperature gear at better prices than Omega.

Off the shelf Ramp/Soak PID controllers remain around $150 with a case and SSR; I'm not up on the Arduino versions, but I've heard you can get down to around $50 for these.

That cleans me out as far as he buying guide goes.