Roasting Coffee in A Bread Machine

Continuing our foray into roasting, we now explore roasting coffee in a bread machine using a heat gun as our heating element. We already posted about roasting in a popcorn popper, which will yield good coffee and is a cheap way to get into roasting your own coffee. But in the popcorn popper you lack the ability to control the temperature so you cannot vary your roasting profile to tweak the flavors of all your different coffees. You are also limited to 6-8oz. of coffee per roast in the popcorn popper. Roasting in a bread machine is a little more expensive but gives you much greater control over your roast and allows you to roast significantly larger amounts of coffee.

To roast coffee in a bread machine you will need:

• A bread machine with a “Dough” setting.
• A heat gun that will blow up to 900-1000F air.
• An apparatus to hold your heat gun.
• A large cooling pan.
• A thermocouple or infrared thermometer.
• A scale, stopwatch, notebook, pen or pencil. (These are optional, but recommended if you want to keep roast-profile notes.)

It is important to note that you will probably not want to use your bread machine for bread after roasting coffee. You can pick up a used machine from your local Goodwill/thrift store or on eBay and save a few bucks and also avoid ruining the family bread-maker right before the holidays.

A bread machine is ideal for roasting because it is built to withstand heat and supplies sufficient agitation for an even roast. The first thing we recommend you do is remove the lid of the bread machine; this isn’t completely necessary but it makes it a lot easier when it’s out of the way. Next, set it to the “Dough” setting and run it without any coffee so you can see how it is going to work. Our Oster goes through a 7 minute “kneading” process where the mixer goes through a series of 3 revolutions followed by 1-second pauses. After “kneading” it spins up to full speed and mixes continuously. Again, we recommend a dry run so you know exactly what your machine is going to do. We use the “kneading” period as a time to warm up the mixing area by getting our heat gun pointed into the mixing chamber and running our heat gun at 60% (about 650 degrees). This will help you ramp up the temperature of the beans quickly at the beginning of the roast.

In addition to the bread machine, you’ll need a heat gun capable of temperatures between 900-1000 degrees Fahrenheit. A powerful heat gun is important because the beans need to reach their maximum temperature in as little as 10 minutes (or at the longest 20-25 minutes). The time and the temperature will greatly affect the flavor of the coffee and can bring out or mute the natural flavor of the beans you are roasting. If you are buying a heat gun to do this, get a powerful one with as many temperature settings as possible. We got a Craftsman Industrial for about $60 that has 2 fan speed settings, 30 temperature settings, and has a maximum temperature of 1030 degrees. You can get a 1200-Watt model capable of 720F and 900F on Amazon for $12.99. You also need to decide how you are going to hold your heat gun over the bread machine. I was able to build a stand for less that $20 using one 8′ piece of 2″ PVC pipe and some basic fittings (I will post the instructions to build this type of stand later). You can also support your heat gun with clamps. However you do it, it is important that the tip of the heat gun only dip down about 1″ into the bread machine. Any further and the sustained heat will start to melt the housing of your heat gun and could also cause it to overheat.

With your bread machine, heat gun, and stand, just get your beans and you are ready to go.

For this roast we are going to roast 1 pound of Kenya Nyeri Ruiruiru Peaberry we got from Sweet Maria’s. We ran the machine and the heat gun through the “warm-up/kneading” and as soon as the bread machine shifts “mixing” we add the beans. The temperature of the bread pan at this point is about 330 and the temperature of the beans before we add them is 69 degrees.

During the “warm-up” the heat gun should be at 50-60% but as soon as you add the beans bump it up another 10-15%. At the beginning of the roast it is important to get the temperature of the beans to around 300 degrees as quickly as possible so you should adjust your heat with this in mind. Now just monitor your the temperature of the beans and increase the heat according to your own profile.

You can see in the last few pictures that we are getting a lot of chaff flying off our beans. This is a good sign that you have sufficient stirring and agitation of the beans. As mentioned, these beans are peaberry, which seem to have a little more chaff than others.

The above photo is right before we stopped the roast. This is the very beginning of the second crack, and you can see the beans have the expected color and they are starting to give off a little smoke. This is my favorite part of the roast. The smoke smells of rich, baked cinnamon with cloves. Interestingly enough, all the coffee we have roasted so far gives off the same smell at this point in the roast, regardless of the specific flavors and notes of the coffee.

There you have it, our Kenya Nyeri Ruiruiru Peaberry roasted to Full City ~ Full City+ with just a bread maker and a heat gun. To cool our beans we spread them one layer thick on a large cookie sheet and put them in a freezer, making sure to stir them and and only cool them to room temperature (i.e., enough to cease the roast).

I took temperature readings at 30 second intervals during this roast and plotted the roasting profile.

The two main increases can be seen at time 0 and a smaller increase at about 6 minutes. The increase at the beginning is to try and avoid “baking” the beans by letting them roast too long at a low temperature, and the second smaller increase is to get the beans to first crack, which happened at about 7:30.

So far, we are very pleased with the roasts we have produced in the bread maker. This Kenyan Peaberry is a pleasantly bright, highly floral cup with a clean finish. The brightness is a little overpowering when only roasted to city+ , which is why we roasted this batch to FC. Roasting in a bread maker gives you a much greater level of control than the popcorn popper and at the same time it is possible to roast a significantly larger amount of coffee.

If you have any questions about roasting in a bread maker or any of the other roasting methods we have covered, please feel free to contact us or leave your questions in the comments.

Share This