How to Roast Coffee at Home, Chapter 1: Beans from Java on a (Retrofitted) Behmor


    We've gotten some questions recently about how to roast our green coffee beans using the Behmor. So we measured out 12 oz of Java Bondowoso and took detailed notes and measurements to share. If you find this post helpful, please let us know, you can message us here through the website.  Also, we'd love if you share this post through social media and tag us.  You can find us on Facebook, Instagram, and Twitter.

    The Short Answer

    The Long Answer

    Home Coffee Roaster: Behmor 2000

    Despite the well documented and sub-optimal user interface, the Behmor 2000 still offers the best combo of batch size, controls, price and...ability to add a thermometer in the green coffee beans. (If you want our thoughts on other home roasters, let us know you can message us here through the website.  Also, we'd love if you share this post through social media and tag us.  You can find us on Facebook, Instagram, and Twitter.

    NOTE: Adding the temperature probe this way will definitely void the warranty, so if you don't want to void yours, check back with us as we publish roasting notes of our other green coffee beans.

     

    Batch Size12 oz (340 g)

    Even though the Behmor is theoretically capable of home roasting up to a full pound (454 g) of green coffee and can even do as much as 20 oz (which exceeds the manufacturer's specs), we tend to roast in 12 oz batches. The reason? Simple: evenly roasted coffee beans. This is especially true on older models of the Behmor that have the slower motor. 

    Since green coffee is 10-12% water by mass, you can expect to end up with ~10 oz of fresh home roast coffee.

     

    Button Sequence: 1, Start, P5, D (Timer will default to 18:00 with this sequence)

    Load the beans in the drum, close the door, and press these buttons in this order:

    • 1
      • Since our batch size is between the 1/2 lb and 1 lb settings, it's better to round up
      • You can always start the cooling sooner, but the Behmor has built-in max time safety features, so if you start at 1/2 lb, you may not be able to hit first crack
    • Start
    • P5
      • This is the maximum power setting; we will lower the power setting later in the roast
    • D
      • Pressing D increases the drum speed, which helps ensure a more even roast level throughout the batch

     

    Pre-heat/Initial Time Adjustment: None

    Because we added the temperature probe in the bean mass, pre-heating the chamber (also known as a "charge" in the parlance of the industry) and adding the drum is cumbersome. That said, when we roast on our other straight-out-of-the-box Behmors, we sometimes pre-heat, depending on the batch size (especially larger than 12 oz), roast level (if you want to go to a dark roast...not approved by the manufacturer), or roast profile. 

     

    home roast profile of green coffee beans first crack at 388 fahrenheit

    First Crack (1C): 1:41 remaining, 388 F (bean), 352 F (exhaust), 267 F (chamber)

    First crack (1C) started a little more than 16 minutes into the roast (16:19 to be exact). Given that the Behmor counts down from the initial time of 18:00, there was 1:41 left on the timer. If you buy some Bondowoso from us and try to replicate this roast on this machine, you may not hit 1C at exactly the same time, though it should be fairly close. This is most likely a function of ambient temperature, the number of other appliances you (or your neighbors) have running at the same time, whether you used an extension cord or not (again, we ignored the manufacturer and used an extension cord) and possibly even the age of the machine. We haven't rigorously tested that last one, but we have some anecdotal evidence that our older models take a bit longer on the same bean/batch size combo. 

    Note that we said "first crack started." like popcorn in the microwave, you'll hear a few initial pops, then gradually the rate of pops will increase, crescendo, then taper off. It's important that all the beans finish first crack (1C). If you press "Cool" at the start of first crack, a good portion of the batch will be under-roasted. 

    We were curious to see how the bean mass temperature (as measured with the thermocouple we added) lined up with the Behmor's temperature read-outs. During the roast, if you press A, you'll see the exhaust temp on the time display, and if you press B, you'll see the chamber temp. In the graph above, the solid blue line is the coffee bean temp, the orange diamonds are the exhaust, and the gray circles are the chamber.

    Our extra thermocouple logged the coffee bean temp every second of the roast, and we manually logged the Behmor's exhaust and chamber ever 30 seconds. Clearly, the exhaust temp is a much better proxy for the bean. And the fact that the exhaust fan only starts about halfway into the roast doesn't really matter, because the beans had changed from green to yellow, but weren't even light brown. In other words, the exhaust temp will catch up to the beans well before the start of 1C. 

    In-flight Adjustments: Time, None; Power, Press P3 at the beginning of 1C

    We wanted an evenly roasted medium, so at the begining of 1C, we pressed P3 to reduce the power. This enabled the beans that had already passed 1C to slow their progress, while letting the rest of the beans catch up. 1C lasted about a minute, so we could've started the cooling cycle as soon as the pops waned (which would have given us a light roast). But we wanted a medium roast, so we let the default timer run out.

    Cooling Method: Open Door

    Despite the chaff mess created by open door cooling (i.e. simply open the chamber door at the start of the cooling cycle), we have done several side-by-side taste tests on roasts where the only variable was cooling method, and open door is the clear winner. Closed door (i.e. how the machine was designed to be used) isn't bad, it just tends to result in a less interesting cup.

    Result: We got a savory full-bodied medium- dark roast, it was dominated by dark sugar notes like chocolate stout, brulee'd sugar/toasted marshmallow, cola syrup, and clove.