I was sick for a while, and was not roasting.

Finally had a chance to convert my PID to use ET, roasted twice using ET.

Here is the last roast.


There is a little ramp at the end. That's where I slowed down the fan a little. At some point, my temps stall if I don't lower airflow, so I lowered the fan speed, and things started moving again.

1st crack was at 9 mins, stopped roast at 13 mins. I should have slowed the fan down a little earlier I think, otherwise I was happy with how it looks on paper, just have to see how the coffee came out now.

Randy

Looks good Randy. And the offset looks stable and predictable which makes temperature profiling easier. Interesting you get the increase in ET when you reduce the fan speed -- When I decrease fan speed, the PID adjusts to keep the ET on target.

I normally roast 140 or 150 grams in a batch, and I set the fan speed to move the beans enough so I don't need to stir them.

At this fan speed, later in the roast, I hit a point where the ET stops rising, unless I lower the fan speed.

At the point where I lowered the speed, the ET is no longer rising. The profile had ET rising, but the popper can't put out enough heat, at the high fan speed, to make ET rise anymore. At least, that's what I think is happening, which is why you see the temp ramp up when the fan speed is lowered, the PID is trying to catch up to where it wants to be.

BTW, I just ordered one of these chassis
http://www.surplussales.com/Cab-RacksHa...ncl_2.html

I am planning on a Revision 2 PID project. I am going use this bigger chassis, and mount a couple outlets in it, and add a step up transformer and fan speed controller, to use to control the fan speed instead of the variac. I am trying to make it easier to setup. A copy of what you did.

Randy

This morning I brewed a cup of coffee from my Tuesday night roast, and it was very good. I think it was better then most, if not all, of my previous roasts with the bean I used, but it could all be in my head too

I would like to try the same roast, taking BT a little further, to get the bean a little darker, and see how it compares.

I also brewed the decaf bean I roasted on Monday, and I thought it came out very good also.

I have not been confident enough to give any of my roasts away, but with a little more practice, I might start giving to a few close friends.

Randy

I really like having a PID for roasting, but there were some things I did not like about my cheap PID, so I decided to improve it.

Here is the new schematic


I put it in a much larger box, so I could add the things I wanted.
I put two outlets in back, one for the fan, other for the heater.

The transformer boosts the AC up to around 140V, and I have a dimmer to control the fan voltage, and I also have an analog voltage meter so I can monitor the fan voltage.

I also added switches, for fan, heater and PID power. It is much nicer to be able to flip a switch, and turn things on and off. With my previous setup, I had to unplug things.

It is also much nicer to have the transformer/dimmer to control fan power, so I don't need to lug around my variac to roast.

I will post some pics of the new, improved, not as cheap, PID.