Should You Wash Green Coffee Beans Before Roasting?

Washing coffee beans before you roast them isn’t the norm, with most coffee enthusiasts recommending against it.

While it is unusual, some cultures do wash coffee beans before roasting them.

If you are concerned about bacteria or washing off the chaff on the beans, you need not worry, as the roasting process is at a temperature that kills bacteria, and the chaff will naturally fall off.

What does washing coffee beans do and why you shouldn’t wash your green coffee beans

The International Coffee Organization says the accepted moisture content of a green coffee bean is between 10 to 12%, meaning most of the coffee beans brought will fall into this range.

Coffee beans are also known to be hygroscopic, absorbing moisture from the air or nearby items, one of the reasons to keep coffee beans in an airtight container.

By washing green coffee beans, they will absorb a considerable amount of water, increasing their moisture content by a great deal and becoming well over 12%.

Roasting a wet coffee bean can become problematic as you will find the beans burn on the outside but are still raw in the middle.

Inconsistent roasts are why you should avoid washing green coffee beans. The absorption of moisture and the potential of an uneven roast will leave you with poorly roasted coffee beans, leading to poorly brewed coffee.

You can’t save bad beans.

To clarify, the only time I’ve come close to washing my coffee beans was when I dropped them onto a dirty table. It was a brief rinse under water before thoroughly drying them.

Looking back, I did notice a difference in taste. The coffee seemed to be duller than my usual brew. At the time, I blamed my roasting abilities, but it seems that the washing could have played a factor.

Why do some people wash coffee beans before roasting them?

Green Coffee Beans on Table

There are instances where coffee lovers have washed their beans before roasting them. An example is washing them before pan-roasting can lead to desirable results.

An article about an Ethiopian lady is on the internet. It shows her going through the process of pan-roasting coffee beans she has just previously washed.

She washed the beans thoroughly for 10 minutes before throwing them still wet into a hot pan.

As soon as the beans hit the hot pan, they begin to stream. Within 5 minutes, the steam has evaporated and turned to smoke while the roast seems even.

While I’ve never tried this method, in theory, this method allows the beans to become hotter before caramelizing. 

Another coffee enthusiast washed the beans, re-dried them, and then roasted them. The coffee enthusiast was pleasantly surprised with the cleaner taste of the washed coffee beans but noted it was not as flavorful.

During this video, you will notice

  • The washed coffee beans appear darker than the unwashed ones.
  • The chaff coming off the washed coffee beans is lighter and more evenly colored compared to the unwashed. The unwashed produced more chaff and a wide range of darkness.
  • The coffee enthusiasts describe the flavors of washed coffee beans as a cleaner but not as flavorful.

I’ve never tried these methods. The coffee lovers I know that have, have reported mixed results.

So try it at your own risk.

Summary

The choice of washing coffee beans before roasting them is up to you. The risks of an uneven roast and extra time washing them far outweigh the minimal and almost non-existent benefits.

I’d only consider washing them if I was about to pan roast my next batch, otherwise, the thought wouldn’t cross my mind.

Washing them before roasting will leave you more often than not with bad-quality coffee.