Roasting beans at home

Does the idea of roasting beans at home seem crazy? Well I roast my own coffee. Well I roast my own coffee, so it can’t be crazy, unless… uh oh.

You start with the raw, green coffee I describe here and then you cook it the way I describe here. That’s the basics, but getting it just right requires experimentation. But making espresso at home is all about experimentation.

Roasting coffee seems is an advanced coffee topic. But it’s not one that requires a huge investment as we’ll soon see.

Why roast coffee at home?

Aside from the experimental excitement, roasting coffee at home guarantees you a fresh batch of coffee. Raw coffee beans last for several months! You can roast what you need when you need it and not have to worry about always hitting up your local roaster.

There’s also an economic advantage since you’re not paying someone else to roast it and you can buy in bulk. But keep in mind that by weight/mass an unroasted coffee bean contains a lot of water that’s cooked off during the roasting process. For this reason the price of roasted and unroasted coffee can be tricky to compare.


Roasting coffee isn’t too complicated in theory. You get the raw coffee beans hot enough and they will make a “crack” sound. That’s called the first crack. At this point you have a very, very light roast.

Continue the heating and you’ll get to a second crack at a fairly dark roast. Heat more and you’ll get darker beans; but they’ll get burned spots at some point if they get too hot!

The tricky then about roasting is getting the best flavor you can out of the bean. For this, the provider of raw beans should have some general advice. From there, it’s up to you to experiment a little to find the best roast for the bean.

Let’s go into some specific heating methods.

Roasting in your oven

Once you’ve found some raw coffee beans to roast, you can always thrown ’em in the oven. Just put the raw beans on a cookie sheet or pan in a pre-heated 500 degree oven. Even a hot enough toaster oven will work (hint: you may need the broil setting.)

Check the beans periodically until they get as dark as you like. Then remove them and place them in a metal colander and cool them by stirring.

Roasting in a popcorn popper

Got an electric popcorn popper? If you have the kind where the popcorn blows around in a circle, that’s the kind that works for roasting coffee. The kind with the screen that blows popcorn up will NOT work!

The trick is to manually spin the coffee beans with a wooden spoon every few minutes until they spin on their own. You will get a lot of chaff in your face.

Cool the beans with a spoon and a metal colander just like in the oven method.

My first roasting experiments were in a West Bend Poppery II, a popular but obsolete model you can find at thrift stores for dirt cheap.

Roasting in a home coffee roaster

The market is small, but there are home devices for roasting coffee. I use a Nesco “Professional” Roaster. I wouldn’t want to go back to a popcorn machine at this point.

Dedicated home roasting machines are better than a popcorn machine or oven for two reasons:

  1. Less messy. Roasters include some type of chaff collector, and sometimes a smoke reducer.
  2. Easier to use. Roasters have a timer to get exactly the roast you want. And there’s usually some type of cooling cycle so there’s no need to cool manually.

Dedicated home coffee roasters aren’t terribly common and can be a little expensive due to the limited supply. But if you’re serious about home roasting, they’re totally worth it.