Level: Apprentice/Alchemist

Reading time: 16 min

Is 'Behmor' impossible to adjust temperature in any profiles?

I read your articles of Behmor and all I could see was the 'Power(%)' of heat and time.
Not exact temperature.
So it looks as if I can roast beans with fixed profiles only.
Because I like to roast with flexible (manual?) temperature and time running.

I understand you believe you want temperature control.  I’m going to lay out why that really isn’t the best way to roast and why power input is the superior way to roast.

And to be clear, it isn’t impossible to adjust temperature in any profile.  What is impossible is to SET a temperature in any profile.

I have noticed a trend as more and more people get into making chocolate and roasting their own cocoa.  They want simple directions.  They want one number. They want one perfect way to roast all cocoa beans.

Although it breaks my heart to tell you, there isn’t just one way to roast well .  I’ve honestly tried for years.  People desperately want me to say “Roast 2 lbs of bean at 350 F for 28.5 minutes” and you will have perfectly roasted cocoa.  But I have tried it and it just doesn’t work out well.  I mean it might be an acceptable roast.  But it also might be bad.

On more than one occasion I’ve had now experienced chocolate makers come back to me and basically apologize for thinking at the beginning of their roasting career that I was just making roasting too complicated.  What was all this stuff about profiles, and continuously turning the temperature down as your roast progresses?  That was until they roasted a while and discovered what I wrote was correct.  That it was not as simple as baking a loaf of bread at one temperature for a set amount of time.  In most cases we both had a good laugh (about them apologizing for something they thought and never said) and we moved on.

In my personal opinion to roast really well you absolutely need to understand what is going on.  

‘Roast 2 lbs on P2 for 18 minutes’ is not understanding.   It is being an automaton.   It is wading around in the shallow end of the pool.  And sometimes you need to do that.  But that isn’t going to teach you how to swim.  It just starts showing you that water isn’t anything to be afraid of.  Eventually you have to float, and paddle and venture into the deep end. 

 ‘Roast 2 lbs on P2 until you hear beans pop’ is better.  It makes you pay attention.  It makes you make a choice.  It gets you to lift your feet off the bottom of the pool and NOT drown.

So in an effort to teach you how to roast, I want to try and teach you what is going on when you roast and how different settings affect, or more importantly don’t affect, your roast.

Have a look at this graph.  It is a pretty classic roast profile from my Royal #5 roast.

The first thing I want to point out is that  ‘2 lbs at 325 F for 30 minutes’ is an illusion.  Most of the time of the roast the ambient temperature is never at 325 F.   The themostat is set for 325 F.

 It is something lower as the graph shows.

There are three important things on it.

1.       The temperature of the beans.

2.       The temperature of the surrounding chamber (ambient)

3.       The vertical lines denoting power input

What is conspicuously absent is temperature control settings.

Let’s talk about what is going on here.  I introduce the beans when the ambient temperature is about 325 F.  That temperature immediately drops.  At around two minutes we finally get real numbers again.  Before that the temperature sensors are madly trying to adjust to the new real temperature.  I note the point at which both temperature start to rise again (this tells me the data is real) and note how quickly the temperature is increasing.  About a minute later I see the temperature is rising a little faster than I want (purely from experience do I know this, which you will gain over time) so what do I do?  I turn the heat INPUT down.  By about 20%.  I don’t turn the temperature down.

Most new roasters want to turn the temperature down.  I get it.  It makes sense.  But it is flawed thinking. 

For the sake of argument let’s say we had a dial like on your home oven that was marked 350 F and we run the scenario again and see what really is happening.  We dump the beans in and as expected they temperature drops.  Your roaster’s thermostat sees that it is less than 350 F so it turns the heat on.  So far, so good.  We get past the turn around point, temperatures are rising again, and again you notice the temperature is rising faster than you want.  What do you do?  Seems reasonable to ‘turn the temperature down’.  Ok.  What temperature?  300 F seems quite a bit lower, so you do that.  What happens?

Well, the thermostat looks at the ambient temperature, sees it is a little less than 200 F…..and leaves the power on 100%.  That is how thermostats work.  All or nothing.  Even if you turn it all the way down to 200 F the power will stay on 100% and you will have changed nothing at all.  Your beans would keep on rising just as they had before.  You would need to drop your setting to under 180 F to get ANY control at all.  And then it is just going to turn the power off.   100% off.    Once the temperature of the chamber drops below the 180 F it will turn back on.   This will tend to give wildly unpredictable results that are very hard to repeat.

Read that again and REALLY let is sink in.  Thermostats like you find in your home oven either turn your oven 100% or 100% off.  That works ok where something is baking for a long time and you need mostly just an average temperature, but it is tantamount to no control when you need to fine tune your roast.

In theory you could continuously turn the thermostat up and down and up and down….but do you really want to do that?  I doubt it.

When I teach roasting in person (yes, I do that and will be putting together a roasting seminar this year) I often talk about driving and how really roasting and driving are very similar.  Driving is complex.  Speeding up, slowing down, not peeling out when you start, not over shooting the line when you stop or causing your seat belt to lock up.  Most people take months to learn and years to master it.  But virtually every adult does it now without thinking.   That is how I want you to roast; in control and in many ways without thinking about it.

How well could you drive if you could either floor it or coast?  It would be hell, wouldn’t it.  But that is what you are asking for with temperature control.  You are asking NOT to have a throttle.  That sounds insane doesn’t it?  What you want is a temperature display, like a speedometer.  You want to know how fast you are going and you want a throttle.  It's hard to impossible to drive in busy and congested traffic with cruise control but that is basically what you are asking for.

Do you remember learning to drive.  When I was taught it was by putting the car in gear, and taking my foot off the brake.  I was admonished to not touch the gas pedal.  I was taught to break…nice and easy.  Not 100% by stomping on the brake.  A little.  20%, then 20% more, easing to a stop.  Only once I gained a little control was I allowed to GENTLY push on the gas.  I learned what it felt like and gained some muscle memory through repetition.  Eventually I was allow to accelerate and brake faster and faster.  I gained control.  Eventually I could predict how hard I could press the gas and not get out of control and how hard or easy to press the brake to stop in a certain distance.  But it took time, work and lots of effort.

This is virtually exactly how I learned to roast, how I now roast, and how I want you to roast.  And it is very possible I have not done the best job explaining why I layout certain ways to roast.  They have always been with the intent of teaching how to drive your roaster.

Okay, I seem to have gone down a bit of a side tangent.  Let me see if I can pull it back.

You brain is the most amazing control system.  It is what I want you to eventually use to control your roasts…if you want to.  What I want you to get away from thinking that on/off thermostat control is….well, control.

Enter the Behmor 1600.  It has profiles.  It is somewhat smart and has some control.  It certainly has more control than an on/off thermostat.   

You recall how I said you could turn your oven thermostat up and down to turn the heat on and off.  This is partly what the Behmor does.  But it does it smartly.  It does not do it solely based on temperature.  It does it in predetermined cycles.  If it gets to a point in it’s programming where it needs 80% power then it cycles the heater in a 8:2 pattern.  8 seconds on, 2 seconds off (disclaimer, I don’t know the actually length of the cycle – the times are just examples).  If it wants 50% power, it is a couple seconds on and a couple off.  But it also has temperature limits.  At a given points there are temperature limits.  If the ambient temperature goes too high it starts cycling.  It doesn’t just turn off the heaters like an oven.  It does it smartly.

Why would you want to take that away from the Behmor?

What you should do is let it teach you how to roast.  Pick a bean, and weight and a profile and let it do its job.  Just like letting your foot off the brake.  Your ONLY job at first is to stop the roaster.  When you smell baking brownies or hear a couple pops, then you hit cool.  Along the way you are noting the smells.  You are learning when a given smell shows up and when it disappears. You are gaining experience.  You will extend some roasts, you will have some go shorter.  You will make chocolate from them and make correlations between roasts and flavors and your preferences. 

Eventually you may take it into Manual mode where you can adjust the power level.  But you won’t do it for the entire roast.  You will take baby steps.  Maybe you will extend the roast 4 minutes by dropping the power 20 or 40% during the last quarter of the roast.

What you will NOT do is worry about what temperature of the beans are.  Nor will you worry about what temperature the chamber is.  Eventually you may care but right now it is just too much data that won’t help you learn.  If anything it will get in the way of you learning.  It’s like worrying about the gear ratio or rpms of your car when you are first learning to drive.  That information helps you how?

But I want to match profiles of those I read on-line I hear you saying.  And I’m saying no you don’t.  Unless you have their roaster, roasting their beans in their environment it is virtually useless data.

The really ONLY useful data is the bean temperature profile (the red line in my graph).  The blue line (ambient temperature) is 100% useless except as a way to explain a roast and reproduce it in the future.  And ONLY if it is data you collected on your roaster.  I simply cannot stress that enough.  It is the amount of gas you are giving the car.  Someone else’s 300 hp car’s throttle has no relationship to your 150 hp throttle.

And besides, you don’t have the bean temperature in the Behmor and this bears repeating.  The ambient temperature of the chamber has a TERRIBLE correlation to bean temperature.  Why?  The biggest issue is ambient temperature.  The Behmor draws in cool air.  That radically affects the chamber temperature.  It is really no more complicated than that.

If anyone tells you different I'll bluntly say they are wrong. And ask them to convince me otherwise.  I will bet they can't.

You say you want to manually adjust the temperature.  My question to you is what temperature?  The ambient temperature that does not correlate to bean temperature?  That just doesn’t make sense.  You need to control power and observe temperature (which you can do – it’s in the manual).

That all said, it really isn’t terribly hard to find the bean temperature of your cocoa in the Behmor.  Keeping in mind it will void your warranty;  you just need to drill a hole through the two walls on the left side of the roaster, plus through the shaft of the drum and insert a rigid thermocouple probe.  And I admit it is handy to have that final end bean temperature.


 I know, that was a lot and there is going to be a lot more this year.  I want to dive deep into roasting.  Too many makers out there are roasting too low and too long because that is the only way they have worked out how to get consistent roasts.   And to their credit they make good chocolate.  But it is my opinion they could make it even better.

There is a saying in coffee roasting.

 “Coffee roasting isn’t about turning green beans brown.  Anyone can do that.  It is about how you get there.” 

Temperature profiles are how you get to that final bean temperature and are absolutely critical to flavor develop and much more important than that final temperature.  At least that is my very biased take.

For now, if you are going to use a Behmor 1600 then accept it for what it is and can do and don't try and make it do something it was not programmed for.