Roast Coffee in a Cast Iron Pan (The Long Answer)

We posted on Instagram about roasting your own coffee at home, and got asked to do a "how to".  So after some thought we realized there are many simple tools you probably already have at home which you can use to roast coffee.  This post will be the first of a four part series outlining how you can easily roast coffee beans in your home with items you probably already own in less than 20 minutes start to finish.

First, we'll start with a cast iron skillet and your stove, since that is what we posted on Instagram.  Let's begin by outlining what you'll need to get started:

  • Cast Iron Skillet
  • Stove burner
  • Stirring utensil, we used a bamboo spatula
  • Unroasted or Green Coffee Beans, we used our Brazil Chapada de Minas
  • Mesh Sieve or Colander
  • Container for Roasted Coffee

Alright, now we're ready to begin!  First, turn on your stove to high heat and place your cast iron skillet on top, you will also want to turn on your vent hood fan.  Next weigh out your coffee beans, we used 265 grams of coffee beans in our 10 inch skillet.  You'll want the coffee beans to cover the bottom of the pan, but not to fill the pan so much you can not stir vigorously without spilling the beans.  Having enough coffee beans in the pan will help distribute the heat more evenly, and prevent us from getting overly burnt sides.  Unlike Julia Child's famous advice about mushrooms, we do in fact want to crowd the beans so that they will cook or roast all the way through rather than just on the surface.

After about 3 minutes you'll begin to see the coffee beans changing color.  They will go from green, to a pale yellowish color.  This means that the beans are starting to roast.  Keep stirring throughout the process so that the beans cook evenly on all sides.  We found this to be the most challenging part, especially while trying to take photos and video of the process.

 Don't worry keep going!  By 7-8 minutes you are probably seeing the coffee beans start to brown, and they may even begin to make an audible popping or cracking sound along with some smoke.  This is good!  You're well on your way to getting those beans completely roasted.  The sound is caused by the build up of steam inside of the cell walls of the coffee, at this point the pressure is too great and the cell walls are breaking and releasing that steam.  In professional circles of coffee roasting we call this "first crack", it is one of the key signs of roast development.  In fact, at this stage we're at the lightest roasts that you'd probably want to drink as a coffee.

Now we need to decide how dark we want to roast our coffee.  For my roasts, I generally prefer a medium-light roast, so I kept roasting.  I also noticed that my beans we're not roasting as evenly as I would've liked. I think because I wasn't able to stir as much as I'd like while trying to take photos and video.  I roasted until my coffee was a fairly even caramel brown tone. (see photo)  And then dumped the coffee into my sieve to cool.  Using the sieve or colander to cool the coffee really helps to stop the roasting process.  You could also try using a baking sheet and a fan.

If you wanted to roast darker that is very easy, just keep your coffee beans in the pan and keep going.  The beans will continue to darken and you will be able to decide what color you like you're beans.  Eventually you will even hear a "second crack" as the beans continue to cook.  As we hit this point, we're solidly in the "dark roast" category.  We'd advise that you probably stop somewhere around this point, as continuing to roast the coffee will eventually turn it to charcoal, and it may even catch fire.

This morning, we brewed a pot and to be honest I was surprised by the result.  I had been worried that the roast was too uneven, and would come out tasting weird.  In the end however, we got a smooth and mellow cup.  All that to say, it is easier than you think, and we should've probably relaxed a bit, and enjoyed the journey!

Please feel free to ask us any questions you have!  And stay tuned for other ways that you can roast coffee at home.


Happy Roasting!

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