Behmor

[julesinoz2010]

Thanks CafeLotta.

Machine is almost brand new...no probs there. Set the voltage to 230 since thats the nominal for Australia (well thats what I read on the internodey web thing). Other roasts went fine - but without a reference its fairly difficult to know if I am on the right track--would have to be doing this side by side with another machine.

So regarding your 1lb P2 roast's. Do you see the internal temperature drop off during that power down phase half way through?? I assume you have thermocouple installed - perhaps you don't?? Then the question is somewhat irrelevant eh.

How does one decide what profile suits what bean?? There is mention of Hard Bean/Soft Bean - how do I find out this information to match to a profile??
Is there a rule of thumb that I am missing?
Where is this Rosetta Stone Tip for the timing between 1C and 2C. I think I missed that one..??

I thought I knew some stuff - then I started roasting.

All in good time eh

[fruity]

Behmor

Rosetta should be in the manual, and it's also available as an option in RoasterThing.

Most of the stuff is in the manual, so really should be read front to back and understood to get the most out of your Behmor. It does take some practise! I've just started using the P3 profile instead of P2 and have got better results with a Brazilian and Ethiopian, but not sure about the Guatemalan (haven't tasted yet, but doesn't look right). It's all trial and error, but some Googling might reveal what others have used successfully with the same or similar beans.

[CafeLotta]

I have my Behmor set to 240V which is the stated standard voltage in Australia. Last time I measured I was getting 237V at the power point I use for the Behmor. No thermocouple installed. There is a visual drop off of power to the elements in the mid section of the P2 roast as per the graph in the manual.

I generally start with P2 profile on a 1/2lb batch before going to 1lb. Note there is a time difference between 1C and 2C depending on weight. I have noticed that on a couple of bean varieties, P2 seems too brutal when it hits 2C at full power and jumps them straight into rolling 2C. I've tried a gentler heat ramp up like a P4 profile with some success. You may also need to crack the door to release heat after a couple of minutes into the cool cycle if the roast is getting too dark. Refer manual for when to do this so you don't damage the heating elements.

Alot of people seem to go under weight with the 1lb setting but I subscribe to the philosophy that the heavier bean mass retains heat better than the lighter. It also takes longer to come up to temperature. Experiment and find which best suits your requirements. I would imagine Behmor did a lot of testing before settling on their programs. I tend to stick to exactly 1/2lb and 1lb weights for my roasts.

[brettreaby]

re your measurement of 237VAC: was this at the start of the roast on P2? because in this case you have the main heaters ( ~1100W ) BUT not the after burner ( ~500W).

The best time to measure is towards the end when both afterburner and main heaters are operating. as the main heaters will cycle check the voltaqe over a period.

Also the voltage setting ONLY affects the afterburner output from what i can observer: main heaters are either full on or full off.

Andy knows more about all this but prefers to shroud it a veil of secrecy. He could tell us but would have to kill us.

I have my Behmor set to 240V which is the stated standard voltage in Australia. Last time I measured I was getting 237V at the power point I use for the Behmor. No thermocouple installed. There is a visual drop off of power to the elements in the mid section of the P2 roast as per the graph in the manual.

I generally start with P2 profile on a 1/2lb batch before going to 1lb. Note there is a time difference between 1C and 2C depending on weight. I have noticed that on a couple of bean varieties, P2 seems too brutal when it hits 2C at full power and jumps them straight into rolling 2C. I've tried a gentler heat ramp up like a P4 profile with some success. You may also need to crack the door to release heat after a couple of minutes into the cool cycle if the roast is getting too dark. Refer manual for when to do this so you don't damage the heating elements.

Alot of people seem to go under weight with the 1lb setting but I subscribe to the philosophy that the heavier bean mass retains heat better than the lighter. It also takes longer to come up to temperature. Experiment and find which best suits your requirements. I would imagine Behmor did a lot of testing before settling on their programs. I tend to stick to exactly 1/2lb and 1lb weights for my roasts.

[CafeLotta]

There is a visual drop off of power to the elements in the mid section of the P2 roast as per the graph in the manual.

The comment re: "visual drop off of power" was in reference to observing the elements powering on/off to maintain temperature as part of the heating profile when using P2.
OP had made the comment that they assumed I was using a thermocouple, which isn't the case. I have the gear but haven't installed it yet, prefering to use observation and taste before I get distracted with graphs and numbers.

237V wasn't a reference to the actual voltage when the Behmor was in use. Its the voltage at the powerpoint, without the Behmor plugged in and working.

[robusto]

Brettreaby:

Voltage at power point is what the household electricity supply is...supplying, and should always be around 240V AC. Irrespective of the appliance, irrespective of its power draw.

What changes is the watts---the appliance's power. Watts, divided by 240 Volt, will give the amps, which too will change. But the one constant is volts: about 240V alternating current.

It the Behmor is drawing 1100 watts, that will be 1100 watts at 240 Volts = 4.58 amps.

[jbrewster]

Brettreaby:Voltage at power point is what the household electricity supply is...supplying, and should always be around 240V AC. Irrespective of the appliance, irrespective of its power draw.

Not entirely true, heavy loads will cause the voltage on the line to sag (definition of "heavy" here is mainly dependent on the quality of the electrical wiring at your house), this is precisely why some people with PID'd silvias and the like complain about their lights flickering in time with the element being pulsed. Also power is 240V +/- 10% here so your line voltage may be as high as 264 or as low as 216 and still be considered to be "OK".

With a resistive load like the elements in the Behmor the power will vary with the supply voltage.
Taking the 1100W element for example;

P=VI
I=P/V
I=1100/240
I=4.58A (as you calculated)

V=IR
R=V/I
R=240/4.58
R=52.4 ohm

Assuming 220V line;
I=V/R
I=220/52
I=4.23A

P=VI
P=220x4.32
P=950W

Derp, my stats were off, per the message from robusto below, it's a square relationship not Linear so 7% in Voltage equates to 14% on power.

[robusto]

Did I not say, purposefully I may add, ABOUT 240 volts? 240 is the nominal value.

[brettreaby]

oops check your maths!

Not true, heavy loads will cause the voltage on the line to sag, this is precisely why some people with PID'd silvias and the like complain about their lights flickering in time with the element being pulsed. Also power is 240V +/- 10% here so your line voltage may be as high as 264 or as low as 216 and still be considered to be "OK".

With a resistive load like the elements in the Behmor the power will vary with the supply voltage.
Taking the 1100W element for example;

P=VI
I=P/V
I=1100/240
I=4.58A (as you calculated)

V=IR
R=V/I
R=240/4.58
R=52.4 ohm

Assuming 220V line;
I=V/R
I=220/52
I=4.23A

P=VI
P=220x4.32
P=950W

~7% power reduction due to lower line voltage.

It's a nice linear relationship at least, if your line is 7% down voltage wise your power output will also be down 7% (this is only true for resistive loads like the elements in the Behmor, things get kinda complicated with other kinds of loads).

JB - Not sure how you interpret my "around" 240V as being a fixed 240? Anyway I said around, and it will vary. Hence my comment to read it. Phew.

Meanwhile- if your going to give a lecture you better make sure you even know what you're talking about! Power into a fixed electric element (like the main heater on BM) = V2/R. Hence 10% drop in line voltage is 0.9*.9 = 0.81 = 19% power drop. It is in fact a squared relationship. ( check your own example - power drop is 14% from a 7% volt drop)

Also the nominal voltage in Victoria & NSW is 230VAC+ 10%/ -6%. ( which conveniently let the authorities to stick to 240VAC for existing equipment )

The point is line voltage IS quite important to the BM. Line voltage at your power point can be affected in many ways but the most significant is the voltage at your switchboard (i.e. from the supplier ) and after that which circuit you connect your BM to - how long and what kind of cables and what other equipment connected affects this. And as i said before the ONLY way to know is to read the volts at the BM power point whilst its operating. This will also fluctuate during different times if the day.

Notice in BM instructions its quite clear not to use an extension lead. This also allows a further voltage drop and lower heater power.

[jbrewster]

Meanwhile- if your going to give a lecture you better make sure you even know what you're talking about! Power into a fixed electric element (like the main heater on BM) = V2/R. Hence 10% drop in line voltage is 0.9*.9 = 0.81 = 19% power drop. It is in fact a squared relationship. ( check your own example - power drop is 14% from a 7% volt drop)

Oh yeah, brain slightly fried right now I was wondering why my percentage calculation was odd.

Should've just gone straight to P=I^2R never could remember the other formulae in that familiy properly, usually have to derrive them each time.

Also the nominal voltage in Victoria & NSW is 230VAC+ 10%/ -6%. ( which conveniently let the authorities to stick to 240VAC for existing equipment )

Come to think of it, I've some vague recollection of that change, didn't realise they'd reduced the negative threshold though...

The point is line voltage IS quite important to the BM. Line voltage at your power point can be affected in many ways but the most significant is the voltage at your switchboard (i.e. from the supplier ) and after that which circuit you connect your BM to - how long and what kind of cables and what other equipment connected affects this. And as i said before the ONLY way to know is to read the volts at the BM power point whilst its operating. This will also fluctuate during different times if the day.

My point too... I apparently misinterpreted your message. The main thrust was that voltage at the socket *DOES* vary with load, ergo, if you're going to check the voltage you should do it under load, the rambling tangent thereafter didn't really speak to that, like I say, brain moderately fried today...

[brettreaby]

JB all good now we are in furious agreement!

[julesinoz2010]

yep.

Not sure about what the question was any more..oh yeah..I ran with the 230V AC option initially as this is the nominal for Aus (changed to 230V in year 2000)..but from what I gather 240 is what is generally measured at the plug. So I changed it last night to 240V on the Behmor..

Other point was...does anyone have a link or reference to where I can gain information about each bean type (ie hard/soft/high altitude) so I can make some sort of descision about which profile to use on this machine..

And...

Openning the door after a roast after pushing COOL. Manual says wait until 1:50 or so after cool button pushed..?? is this right. I'm not seeing how this would damage the machine..got any reasons/comments

[robusto]

Jules, if you open the door at that point, you will have smoke and chaff blown all over the place through the open door. Kind of defeats the purpose of having an otherwise neat, no-mess machine which can be used indoors.

I find the suggested "rosetta stone" times between cracks very much hit and miss. Mainly miss. So in the last 4 minutes or so, I stay at the machine, and note when first cracks are heard.

If it seems likely the machine will enter the cooling cycle prematurely: during first crack or, if that is completed, long before second crack--- I keep adding more time in 15 second bursts and try---try---to have second crack happening just as, or just after, the cooling cycle begins.

And all this is from a cold start-up. I'd hate to think what time adjustments would be necessary if the recommended pre-heat is done.

[Divey]

I wish you blokes would stop talking in shorthand as I have not got a clue what your on about.

I have only very recently (yesterday) discovered that the sub-station that supplies our power is about 300 metres from our home. Would that have anything to do with me recording 254.6 volts at the power point ???

[CafeLotta]

......Opening the door after a roast after pushing COOL. Manual says wait until 1:50 or so after cool button pushed..?? is this right. I'm not seeing how this would damage the machine..got any reasons/comments

I thought I had heard that opening the door too soon could damage/shorten the life of either the main heating elements or the smoke arrestor element if cool air hits them before they have cooled sufficiently. Can't find the reference at the moment unfortunately.

The manual also states not to stop the roast straight after the roast as this could damage electronic components, probably on the PCB's. I have read of people stopping the Behmor to dump the beans and manually cool them straight after the roast. Guess you run the risk if you choose to do it.