The A/B temps are only intended to be used for general informational purposes/ correlation for rise and fall but NOT to determine roast level etc..

“A” Temp can give you a correlation but as noted NOT bean temp and greatly affected as noted in the following

“B” temp while a reasonable gauge for preheat is not an accurate guide for later in the roast as the elements cycle, given the thermisters location.

Q: I press A and it only reads 129F, do I have a broken system

A: No, as noted in the manual, “A” temperature reading only becomes active midway through the roast. The fact the button works and there is a reading indicates the system functions are as they should be otherwise an error message would likely appear.

Q: I press A and B both sometimes it reads higher/ lower than other times, do I have a defective unit?

A:

No*, the temperature readings of thermistor can be affected by

1) Weight of coffee being roasted/ bean mass (1 lb to 12ounces (454 grams to 336 grams) causes a 17F (appx 9.5C) difference)

2) Voltage as it effects power to the elements, fan speeds, which will affect temperature readings.

3) Venturi opening/ ambient air- to reduce exhaust temps we have a venturi opening and a fan. The opening allows outside air to be drawn into the exhaust channel via the venturi. The fan forces that air into the exhaust channel to mix with the heated air stream which is pushed over the “A” sensor. Outside temperature changes can affect “A” temps greatly.

4) B will be affected by the above and elements hitting set point (elements cycle as designed)

5) Readings can also be affected by the point a button is pressed in processor refresh cycle

6) Thermisters/ Thermocouples all have +/- (plus/ minus) tolerances of anywhere from 1%-3%, which can also play into what readings you are viewing.

Q: My readings are different than others I see posted on the internet, is my system broken?

A: If you are seeing readings on A in the high 200s* (appx 93.5C) NO because as noted above there are

Numerous things that can affect the readings. Never gauge by what others may show because

each environment, can lead to different results.

Q: My temperatures are different from A to B, is my system broken?

A: No, the A reads exhaust channel temps and B reads chamber side wall. “A” is in the air flow,

whereas the “B” is attached to the outer side wall of the chamber thus displays lower temp

readings than A..

Q: My chart shows 1C should be around 400F (appx 205C) but my readings shows well below that, is my

system broken?

A: No, the “A” button only shows exhaust temps and not bean temps with the whole purpose of

showing temperatures being for informational purposes to illustrate the rise/ fall for patterns

only. “B” is sidewall and as noted above can have swings for various reasons as well.

Q: I notice mid roast when a fan kicks on I have a temporary drop in my B Temp. Is my system

broken, or is this normal?

A: This is normal. The program is designed to have a fan come on to pull air/ smoke through

the afterburners to burn off smoke and other impurities so you will see a drop as high heat air

flow is now being drawn over the beans for the ideal results

1) Does this temp drop affect the roast outcome? No, this doesn’t affect the roast as verified by the fact the roaster is used not only for sample roasting and in cases winner of numerous roasting competitions such as Golden Bean Awards.

2) To further illustrate how B drop doesn’t affect the roast cycle is by pressing “A” you will note it is rising in temp which verifies the heat is being directed as intended towards the beans and your roast is not stalling.

3) Heat either :

a) Dissipates because it’s mixed with cooler air

b) Transfers to something else- say coffee beans

c) Redirected by airflow

4) Now given a, b and c… are fact, and heat doesn’t disappear what happens when the fan is turned on?

5) It’s going to redirect heated air (c) transfer heat to the beans (b)…but now with a slight convection effect because heated air is being drawn over bean.

6) Any drop seen in B is directly related to (b) and (c) the heat now is being drawn over the beans to get the opening for afterburners/ draw fan which is why you will see A rise not only because of the afterburners but the heat being drawn in after it passes over the beans…

Q: Recently I noticed my B temp fluctuating, is my system broken?

A: The Behmor 1600, 1600 Plus and 1600AB were designed using an appliance processor in

conjunction with what are called “thermistors”. Thermisters are small resistors intended to

read temps but over time can lose their “sensitivity” due to bean ignitions or continued use

where err2 are generated. The solution here is a new “yellow” thermister.

*If you get a reading on “A” thermistor in the low 200s (appx 93.5C) close to 1C or beyond please check

your afterburners after the roast is completed. Easiest way is to open your chamber door

press COOL, and look up at the grill w/ holes on the inside of the roasting chamber. Can

you see any amber color behind the holes? If no contact us for a replacement set.

While each user can decide on their own, Behmor does not recommend gauging your roast on these temps given the additional data shown above

Article Updated: October 18, 2023