Understanding The Roasting Process at Home

Understanding The Roasting Process at Home

In this article, we’ve provided you with step-by-step instructions for each of the four home methods.

  1. Roast in a pan/grill
  2. Roast in an oven
  3. Roast in a popcorn popper
  4. Roast in a purpose-built home coffee roaster

Your exact approach to roasting will vary depending on your chosen method.

But what never changes is the process:

  1. Beans get hot
  2. Beans get roasted
  3. Beans get cool
  4. Beans get delicious

It’s a simple process with some necessary steps to note along the way to guarantee great results. These important steps hold true for every method.

Let’s take a quick look at what happens during and after roasting so that you know what’s going on while the magic is happening:


  • Temperature: 350F to 500F is the widely accepted temperature range. This varies depending on the method you’re using.
  • Agitation: Your beans can never rest and roast! Constant stirring ensures an even distribution of heat, and thus an even roast.
  • First Crack: After 3 to 5 minutes the beans will produce an audible crack. This crack indicates that your beans are lightly roasted and ideal for white coffee. This the minimum amount of time required to produce roasted beans. Continue roasting and agitating for darker roasts.
  • Second Crack: After a few more minutes another crack is heard. This crack indicates a medium roast. A few more minutes of roasting and your beans will be burnt and unusable. Experiment with times to find your favorite roast.
  • Tip: We usually wait roughly 30 seconds after hearing the second crack.
  • Cool Down: Transfer beans to a metal colander or baking paper to cool. Use two metal colanders (plastic can melt). Shake and transfer your roasted beans between colanders. This cools the beans quickly and removes the chaff.
    Spread evenly over baking paper to substitute for a metal colander. This method is not as effective.
  • Remove Chaff: Chaff is the dried husk of the coffee bean. It is very messy. Cool your beans down outside or in the sink to reduce clean-up

It is one of those things that you’ll get the feel (and eye) for with practice. This video is a good start:

Post-Roast And Chemistry

When you’re roasting coffee beans, you are creating an awesome chemical transformation – the Maillard reaction.

Over 800 compounds are transformed (1) from the boring, flavorless compounds present in the raw beans into the delectably delicious and aromatic compounds found in roasted beans.

In the very early stages of roasting colored plant compounds such as chlorophyll, anthocyanins, etc begin to decompose […] accompanied with subtle changes in aroma from grassy to more toast/popcorn notes.

This is why raw beans smell and taste nothing like roasted beans. The compounds in the beans are waiting to be transformed!

Roasted beans release gas (CO2): This continues for weeks (2​​​) after roasting. Why should you care?

  • CO2 helps to naturally preserve roasted beans by displacing oxygen
  • Oxidation ruins beans. They become stale
  • Too much CO2 in coffee beans creates too much crema (a bad thing)
  • Not enough CO2 creates stale tasting coffee (also a bad thing)

De-Gas: Wait 12 hours before sealing in a container (Allow the initial Co2 to escape)

  • Sealing newly roasted beans in storage too early will lead to CO2 pressurization. This can pop the top off your container, potentially damaging it.
  • Coffee beans that contain too much CO2 will result in an undesirable flavor. Give your beans a chance to de-gas!
  • Opinions differ. From a few hours to a few days. In our experience, we’ve found 12 hours to be a good rule of thumb. Your experience might prove otherwise – do what works for you

Grinding and Storing after Roasting

  • Wait 24 Hours before you Grind & Brew. Beans need a day to mature and reach full-bodied flavor
  • Store in airtight container: Keep beans fresh and use within seven days
  • Coffee is always best when it’s fresh. After more than one week, your roasted beans will begin to turn stale as oxidation does its thing
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