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coffeecat wrote:

After reading Scott Rao's book I started thinking as I tried to wrap my head around the densely packed information therein.

I needed a little more information about the Behmor. To drop at a higher temperature, I was going to need to pre-heat beyond the two minutes maximum suggested in the manual. What would happen? Would it explode or melt down? Fail to restart? I mean, what???

Here's what I found out. Perhaps these data will be useful. They are subject to correction if your experimentation reveals different observations, but, for what it's worth, check this out.

1. When roasting on <auto> mode, the heating elements cut out at 286?F. Not sure yet what the cut-in temperature is. Just realized I'll need to observe that and report back.

2. When roasting on manual mode-- like <P5>, for instance, the cutout temperature is higher-- 296?F to be exact. At <P4>, <P3>, and <P2> didn't get high enough to cause the elements to cut out.

3. At 1/4# and 1/2# setting, fan comes on at 5 minutes.

4. At 1# setting, fan comes on at 7-1/2 minutes.

5. At <P2>, <P3> and <P4> settings the elements don't seem to radiate at 25%, 50%, and 75%, respectively. Instead, they come on at what appears to be 100% for a period of seconds, then de-energize for a period. Here's what that looks like:

<P2> On for 4-5 seconds, Off for 12 seconds.
<P3> On for 8 seconds, Off for 8 seconds.
<P4> On for 12 seconds, Off for 4 seconds.

5. Pre-heating by temperature, rather than time. It's possible to pre-heat to 280?F. The temperature then drifts upward for a bit. After removing and charging the drum and replacing it, actual start temperatures are 240?F to 255?F depending on how efficiently that action is carried out. The 1600 Plus has no issue re-starting for the roast at that pre-charge temperature.

If you decide to pre-heat to 280?, the trick becomes controlling the RoR to 1c such that you don't hit 1c way too high and then experience a reversal of RoR.

This is a bit tricky and requires planning ahead of time, experimenting, and then experimenting some more. Finally, recently I've had some success. Without BT, I'm visualizing total energy in the oven-- thermal masses including beans, and envisioning injecting energy into the system in such manner as to keep it moving upwards at a diminishing rate.

Once the fan comes on, oven temp drops sharply, but fan temp immediately shoots up. Then, the two together, according to my theory, anyway, need to move upward. If we pay attention to the oven temperature only, we will be confused. Once the fan starts, both temperatures need to be considered together.

Using Roastmaster, I plot curves for both at one minute intervals and possibly add intermittent data points when they might prove significant-- dips, rises, 1c start, 1c end, etc. Whatever seems relevant for later evaluation.

I'm no expert, friends, let's be clear-- just an enthusiastic and curious aficionado of good coffee determined to hit as high a level of roasting as possible given the limitations of my understanding and equipment.

I will post results of further experiments here.

coffeecat wrote:

After reading Scott Rao's book I started thinking as I tried to wrap my head around the densely packed information therein.

I needed a little more information about the Behmor. To drop at a higher temperature, I was going to need to pre-heat beyond the two minutes maximum suggested in the manual. What would happen? Would it explode or melt down? Fail to restart? I mean, what???

Here's what I found out. Perhaps these data will be useful. They are subject to correction if your experimentation reveals different observations, but, for what it's worth, check this out.

1. When roasting on <auto> mode, the heating elements cut out at 286?F. Not sure yet what the cut-in temperature is. Just realized I'll need to observe that and report back.

2. When roasting on manual mode-- like <P5>, for instance, the cutout temperature is higher-- 296?F to be exact. At <P4>, <P3>, and <P2> didn't get high enough to cause the elements to cut out.

3. At 1/4# and 1/2# setting, fan comes on at 5 minutes.

4. At 1# setting, fan comes on at 7-1/2 minutes.

5. At <P2>, <P3> and <P4> settings the elements don't seem to radiate at 25%, 50%, and 75%, respectively. Instead, they come on at what appears to be 100% for a period of seconds, then de-energize for a period. Here's what that looks like:

<P2> On for 4-5 seconds, Off for 12 seconds.
<P3> On for 8 seconds, Off for 8 seconds.
<P4> On for 12 seconds, Off for 4 seconds.

5. Pre-heating by temperature, rather than time. It's possible to pre-heat to 280?F. The temperature then drifts upward for a bit. After removing and charging the drum and replacing it, actual start temperatures are 240?F to 255?F depending on how efficiently that action is carried out. The 1600 Plus has no issue re-starting for the roast at that pre-charge temperature.

If you decide to pre-heat to 280?, the trick becomes controlling the RoR to 1c such that you don't hit 1c way too high and then experience a reversal of RoR.

This is a bit tricky and requires planning ahead of time, experimenting, and then experimenting some more. Finally, recently I've had some success. Without BT, I'm visualizing total energy in the oven-- thermal masses including beans, and envisioning injecting energy into the system in such manner as to keep it moving upwards at a diminishing rate.

Once the fan comes on, oven temp drops sharply, but fan temp immediately shoots up. Then, the two together, according to my theory, anyway, need to move upward. If we pay attention to the oven temperature only, we will be confused. Once the fan starts, both temperatures need to be considered together.

Using Roastmaster, I plot curves for both at one minute intervals and possibly add intermittent data points when they might prove significant-- dips, rises, 1c start, 1c end, etc. Whatever seems relevant for later evaluation.

I'm no expert, friends, let's be clear-- just an enthusiastic and curious aficionado of good coffee determined to hit as high a level of roasting as possible given the limitations of my understanding and equipment.

I will post results of further experiments here.