aspiring roasters.

Home roasting has becoming increasingly popular the past few years, and working at a local roasting plant I've have heard all kinds of tales about the 'how-tos' and the methods they have found that work for them. We get the joy of helping these home roasters find a particular kind of green bean that will work for them, something they can practice on. I have heard everything from hot air popcorn poppers to cast iron skillets, one guy made a crazy hot air popper with a metal topper because after melting several tops to his hot air poppers he decided to create something that wouldn't melt :). There are lots of ways to roast at home, and whatever works for you in your roasting endeavor is great, but I want to share a simple way that I have learned of home roasting ...
To start:
You want to preheat your oven to 500 degrees for about 30 mins before putting beans in there, so while that is preheating get your beans ready ...
Make sure that you have a reference color in mind for your beans, something that you can compare colors to (already roasted coffee that you enjoy). Coffee continues to change colors after it's roasted, so if it's not right at the color you want wait ... because it very quickly could be. Think of like a mahogany or a light brown ... whatever you can come up with that relates to a particular color/taste preference. And take notes of what you are doing so that you can have a detailed account of what you've done, changed, and what didn't work. Using a perforated baking sheet is the simplest way to home roast and it ensures that you don't invest more than what you need to and also gives you the chance to try it without losing the investment.

perforated baking sheet

What you'll need:

•  a perforated baking sheet
• an oven that can withstand a 500 degree temperature
• green coffee beans
• 2 medium metal sieves
• a stop watch or timer that shows seconds
• a scale that can weigh grams

How to:

• Put the baking sheet in the middle of the over rack to ensure that it will get even heating.
• You'll want to weigh out the green coffee with your gram scale to know how much weight the coffee will lose in the roasting process.
• Spread the coffee evenly across the baking sheet, no bean should fall over another, but make sure that you only have beans on 1/2 - 2/3 of the baking sheet
• Have LOTS of ventilation, open windows or turn on your range exhaust because you are likely to have smoke rolling ...
• Put the beans in the oven!!
• Make sure that you don't have to oven door open more than 4-5 sconds at a time, you might need a flashlight to be able to observe the beans and see the color brightly.

color difference between green and roasted

The Breakdown:

• At 2-3 1/2 minutes the green beans will turn a more intense green color
• Around 4 minutes it will turn yellowish, you want to agitate the pan so that the outer beans come more towards the middle of the baking sheet.
• At 5 (maybe 5 1/2) minutes the beans will start to turn brownish, a light brown. Go ahead and agitate the beans again swooshing the baking pan around so that they are turning.
• 7-8 minutes you'll hear the first crack ... its similar to popcorn (both go through a heating process to get a finishing product)
• 20-30 seconds after you hear the first crack agitate the baking sheet again, swooshing the beans around the baking sheet
• 45 seconds after you hear the first crack, around minute 9, the coffee is significantly changing in color and taste. REMEMBER to take notes because it will help you in the future with time and taste for batches you'll do in the future.
• Take it out just before you think it's done, because coffee will continue to change colors after you remove it.
• When you remove it from the oven take it outside and use the sieves to pour the beans from one sieve to another, back and forth, holding them an arms length away from one another. This helps remove the chaff from the bean and helps cool the bean down.
• Make sure you weigh it once you are done to see what weight you ended up with.
• Over the next 5-10 days the flavor of your coffee will start to set in. You can drink it sooner, but our Master ROaster suggests waiting a few days because roasted coffee usually is its best 5-6 days after roasting.

metal sieve (collander)

VOILA! You've roasted your own batch of coffee at home, and probably a little safer than a potentially meltable hot air popper. ;) Hope that this helps and maybe creates a new hobby for you, because let's be honest there is nothing like freshly roasted coffee.