Coffee Roasting 121126

I roasted coffee again today taking somewhat better advantage of the heater controller.  As before, I ran the following profile:

• Drive heat to 300F and hold for 5 minutes to dry the beans
• Raise heat to 400 for 2 minutes
• Raise heat to 450 with heat at max to drive through 2nd crack

Here are the profiles

The second profile seemed to work generally well with the heat held at 8 for 5 minutes, then increased to 10 for the remainder of the roast.

I've also improved the chaff collector and remounted the controls so they are all on a single board.

Improved chaff collector and controls mounted on single board

I also tried a simple vertical collector.  This did not work well as the chaff fell back into the beans when the fan was turned off.

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• Coffee Roasting 121115

Coffee Roasting 121116

Did two roast today to test out the motor speed controller that I'm using to control the roast temp.

121116-1 shows that it is possible to control temp using the new controller.  The profile itself is less interesting though I did drive the roast to 2nd crack.  That said, I should probably have left the roast run a bit longer.

In 121116-2 I left both the heat and fan generally along to see what the roast would do.  It stalled after 1st crack so I increased the heat to drive to 2nd crack.   Also the 1st crack happened relatively quickly but took a long time to complete indicating that drying was highly uneven.  Likewise with 2nd crack.

Next time I roast I'll look to drying at 350 or so for the 1st 5 minutes then running to 1st crack quickly and then on to 2nd crack within 2 or 3 minutes.

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• Coffee Roasting 121115

Coffee Roasting 121115

I've rewired the popcorn  popper/coffee roaster so that the heating elements are on a separate AC circuit.  I've connected this to a router speed controller (Amazon RSC 9400) and tested to see what the heat output is with no beans in the roaster and fan on full.  Here are the results:

Several things of note:

• The temperature increase is somewhat linear with the speed control setting.
• Returning the setting to a previous value, in this case 5, returns the temperature to approximately the previous value, but it takes time for the temperature to stabilize.

The next time I roast I'll try running the fan at a more or less constant speed and controlling the roast via the temp control setting.  I'll also try things the other way around, and playing with both temp and fan speed.

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• Coffee Roasting at Home - 121104

Coffee Roast 121114

We've used up all the coffee we had on hand and so I roasted three batches today, 2 Harrar and 1 Mexican.  I've modified the roaster to use a thermocouple to measure bean temp an hopefully get somewhat better control.  The batches went well and we'll taste them tomorrow or Friday.

The motor speed controller arrived today.  I tested it with the popcorn popper to see if it works and it does.  I'll need to modify the wiring and controls to use it but that shouldn't take long.  This should allow me much better control of heat input to the roast and smooth out the roast profile.

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• Coffee roast at home - Part 2 121020

Friends, Getting Old, Cancer & Death

I've had an interesting life and come close to dying by misadventure a few times.  I think death by misadventure is relatively simple, at least in that it is generally unexpected and often quick.  Today I've head to consider another kind of death.  Death by cancer.

A close friend has had cancer for some time.  His cancer is somewhat rare and always fatal.  Initially, when he was diagnosed there was at least some possibility of treatment.  A few months ago the treatment he was on quit working.  Subsequent treatments also failed.  Now he's dying.  Death by cancer.

We had lunch today as we've had lunch from time to time.

Being with someone you've known for a long time and watching as disease takes them touches many many emotions; concern for the well being of a friend when you know there is noting you can do to help save continued friendship, concern for their family and love ones, uncertainty about one's own mortality and manner of death.

These and many other emotions and thoughts, though a natural part of life, are difficult.  Difficult indeed.

Coffee Roasting at Home 121107

I've run some test of the hot air roaster to determine the heat gain profile with no bean load.  Here are the results.

Time - Temp Profiles

While the heater can not drive the temperature to 450 and above, since the roasting process is exothermic after 1st crack higher temperatures are clearly possible.

Coffee Roasting at Home - 121104

We're getting a little low on coffee so time to roast a bit.  I did 3 100g batches today.

121104-4 Mex - Was trying out new chaff collector and not paying a lot of attention to the profile.  A couple of things of note:

New chaff collector works sort of OK but still allows some fine chaff to escape.  I'll see if I can find some finer screen on line.

Fine chaff that escaped screen.  Need finer screen.

Glass chimney cracked from high heat (~500F).  I replaced with a different chimney with a somewhat smaller base that doesn't touch the metal roasting chamber.

Cracked glass chimney.  Replaced with a chimney with a smaller base that does not touch the metal chamber.

Dropped a bit early as roast was just entering 2nd crack.  We'll try and see how we like a lighter roast.

121104-2 Mex - Watched this one closely varying the fan and switching heaters to extend the roast

121104-3 Harrar - Watched this one closely but let the roast run hot and fast

 I blended the beans from these last two roast for an espresso.

After these most recent roast I'm inclined to heat the roaster with both heaters, then turn off one and use the fan to control temperature.  I'm also uncertain of the temperature probe readings as I think it's in the hot air stream and measuring the air more than the beans.  I may try to position it a little better.

In a related matter I found that a scant 1/4 cup of roasted beans is 17g.  The new espresso machine takes roughly 14g for a double shot.  I also found that 1/2 cup of green is 100g, the current load for my roasting experiments.