Roasting coffee beans is an art and a science. As a professional barista with over 10 years of experience, I’m often asked if washing coffee beans before roasting is necessary or beneficial. This article “wash coffee beans before roasting” will examine the reasons for and against washing prior to roasting and provide actionable recommendations.

The journey of a cup of coffee starts with green coffee beans before roasting. These beans are processed and dried, retaining their green color. Once they have undergone the roasting process, they transform into the fragrant and flavorful beans we are familiar with. The coffee roaster plays a crucial role in bringing out the desired taste of the coffee by carefully monitoring the grilling time and temperature. After grilling, the beans are ground to produce the coffee grounds that are used to brew our favorite cup of coffee. The flavor of the coffee is greatly influenced by the grilling process and the quality of the beans.

How to prepare coffee beans for roasting

Ground coffee is a popular option for coffee lovers as it offers a convenient and easy way to brew a fresh cup of joe. One crucial aspect of ground coffee is that it helps to remove the step of grinding the coffee beans at home. Additionally, when it comes to wet coffee, an airtight container is essential to ensure the coffee stays fresh and doesn’t lose its flavor due to absorption of outside odors.

Moreover, washing green coffee beans is a crucial step in the process as it removes the outer layer called the chaff, resulting in a cleaner and better-tasting coffee. The coffee bean roasting process is crucial in determining the flavor of the brewed coffee. During this process, the beans are roasted to bring out their unique characteristics and aroma compounds. However, not all coffee beans are the same, and different types of coffee beans may result in variations in the chaff and an uneven roast.

Green coffee beans purchased in stores are ready for grilling. However, if you are growing your coffee plants or have coffee berries at home, you can prepare the coffee beans for grilling using the following steps.


Coffee plants bear fruits called coffee cherries. You can pick the coffee berries when they are ripe and have a deep, bright red color.


You can remove coffee beans from the cherry fruits, called depulping. Depulping occurs in different ways, for example:

Crushing and grinding the cherry fruit to separate the seeds or most commonly known as coffee beans

Soak the coffee cherries overnight so that the pulp separates from the coffee beans

Squeeze the coffee beans out of the fruit with your hand

Industrial coffee processors use machines called depulpers to separate the coffee beans from the fruit.


Once the coffee beans are extracted from the fruit, they are rinsed or washed. With this method, the fruit residues and remaining pulp are washed away from the beans.


To remove the slippery texture, soak the beans for 24 hours or until you can no longer feel the slimy texture on the coffee beans. You can skip this process and dry the beans directly if you prefer a more natural and fruity tasting coffee.


Green coffee beans should contain 10 percent moisture before roasting. Drying also plays a crucial role in the shelf life of coffee beans. Coffee beans that contain a lot of moisture promote the formation of mold and bacteria, which makes drinking coffee dangerous.

Benefits of wash coffee beans before roasting

Coffee roasting is a complex process that involves transforming green coffee beans into roasted beans with a deep, rich flavor. Before the coffee beans roast, it is important to wash them thoroughly to remove any impurities or dirt. Another reason why people wash their coffee beans is to eliminate a grassy taste that can sometimes be present in unprocessed beans.

Benefits of wash coffee beans before roasting

By washing the coffee beans, the final product achieves a cleaner and more vibrant taste. The acidity of the coffee can also be affected by how the coffee beans are roasted. Overall, the washing and roasting of coffee beans play crucial roles in creating the perfect cup of coffee.

Here are some of the main reasons why some swear by washing coffee beans prior to roasting:

Removing Impurities and Residues

Coffee beans may have small residues of dirt, dust, or debris on their surface from the processing and drying stages. Washing the green beans can help remove these impurities before roasting.

Some also claim washing gets rid of traces of chemical or fermentation byproducts that might impart unpleasant flavors. A pre-roast wash provides a clean slate.

Even out Moisture Levels

Since coffee beans are hygroscopic (absorbent) they can easily pick up moisture during storage and transportation. This can lead to inconsistent moisture levels across a batch.

Even out Moisture Levels

Giving the beans a wash before roasting allows you to even out that moisture and improve consistency between beans. Drier beans will absorb water while wetter ones lose excess humidity.

Improve shelf life

By removing surface impurities and residues, washing may allow roasted coffee to stay fresher for longer. Oils and particles left on the surface can sometimes lead to faster staling.

Washing may extend the shelf life of your roasted coffee by a few extra days or weeks, depending on the roasting and packaging.

According to the International Coffee Organization, washing the beans before brewing is not recommended. The organization states that the coffee beans’ protective layer is easily removed by washing, which can affect the quality and smell of the coffee. However, some argue that it is necessary to wash the beans to remove any dirt or impurities. On the other hand, there are those who believe that washing can harm the coffee beans’ natural oils, affecting the flavor. Ultimately, it is up to personal preference. After brewing, it is essential to clean the coffee grinder to maintain its performance and prevent any residue from affecting future brews.

Lighten roasted flavors

Some specialty roasters believe washing green coffee beans once or twice lightly can remove oils and sugars that contribute to a darker or heavier roast flavor. The argument is that washing leads to a lighter, cleaner tasting end product.

Lighten roasted flavors

For roasting companies aiming for bright and fruity flavors, pre-roast washing may help reduce undesirable roasted or burnt notes.

Drawbacks of Washing Coffee Beans

It is not recommended to wash away some of the natural oils that contribute to the flavor of the coffee beans you’re using. These oils play a crucial role in enhancing the aroma and taste of the coffee. However, if you’re using wet coffee beans, it is advised to remove any dirt or debris by washing them before roasting or grinding. This will ensure a cleaner and more consistent final product.

Washing green coffee beans prior to roasting also comes with some downsides to consider:

Stripping away Inherent Flavors

Coffee beans have a delicate balance of natural oils, sugars, and other compounds that give each origin its unique flavor profile. Many experts warn that washing strips away some of these inherent elements before they even have a chance to develop during roasting.

By introducing moisture you run the risk of dulling or removing flavors through dissolution and dilution. The final tasting notes could become less vibrant.

Adding Moisture Encourages Mold Growth

While washing evens out moisture levels, it also raises them. Higher moisture content means more risk of mold growth during transport or storage of the green beans. Strict drying is required after washing to prevent this.

Adding Moisture Encourages Mold Growth

Higher humidity alone can also degrade bean quality and flavor over time. Roasters have to take great care to prevent mold formation.

Altering Bean Chemistry

Water introduce chemical changes in the cellular structure and chemical composition of coffee beans. This may result in the sugars and proteins breaking down prematurely before roasting.

Some acidic compounds may leach out while the bean absorbs moisture. This can create an imbalance in flavors, losing nuance.

The reason why washing green coffee is important is to prevent the growth of bacteria or mold. This is crucial in the coffee-making process as any contaminants can affect the flavor and quality of the final brew. Green coffee beans have an accepted moisture content of 10 to 12%. By washing them, we ensure that only clean, safe beans are used to make the coffee that we want to drink.

Increasing Labor and Processing Time

Washing adds another step between harvesting/processing and roasting, increasing labor costs. The beans also have to be dried thoroughly afterwards to prevent mold, which takes further time.

For large volume roasters, the extra resources required to properly wash and dry beans can eat into tight margins. It may not be feasible at scale.

No Improvements for Washed Coffees

Coffees that undergo washed processing at origin do not need further washing before roasting. In fact, it may deteriorate quality.

Washed coffees have already had any mucilage or residue removed during processing. Pre-roast washing offers no benefits.

Best Practices: When to Wash or Skip Washing

Taking into account both the potential upsides and downsides of washing, here are my recommendations as a barista:

  • Lightly wash natural processed coffees – A brief wash can remove some impurities without stripping oils and flavors.
  • Don’t wash washed coffees – Avoid washing beans that were already washed during primary processing.
  • Choose mild detergent – Use a mild, flavorless detergent to avoid soapy flavors. Rinse thoroughly.
  • Dry immediately after – Quickly dry beans to avoid mold. Don’t let them sit wet.
  • Sample test roasts – Try test batches washed vs unwashed to taste the difference.
  • Consider food-grade oils – For washed beans, experiment by coating with a light food-grade oil before roasting to retain inherent flavors.
Best Practices When to Wash or Skip Washing

The choice ultimately depends on your flavor goals and preferences. With careful testing and controls, washing can be beneficial for some natural coffees. But never assume washing is universally better.


Should all coffee be washed before roasting?

No, beans that have already undergone washed processing should not be washed again pre-roast. Only natural processed coffees see any potential benefit from light washing to remove surface particles.

What is the best liquid to wash coffee beans?

Use filtered water at about room temperature. Some roasters add a small amount of mild, unscented detergent to help surface impurities rinse away. Thoroughly rinse detergent off the beans.

How long should you soak the beans while washing?

Just a brief soak of 30 seconds up to 2 minutes is sufficient. Extended soaking or agitation can start to strip flavors.

Does washed processing make pre-roast washing pointless?

Yes, coffees processed by the washed method have any mucilage or residues removed early on. Further washing before roasting is unnecessary and potentially detrimental.

How do you dry beans quickly after washing?

Use a dedicated coffee bean drying machine or spread beans out on racks in a well ventilated area. Moving air helps evaporate surface moisture. Don’t let beans sit wet. A roasting coffee beans machine is a device used to transform green coffee into roasted coffee seeds.


Whether to wash coffee beans or not before roasting depends on your flavor aims, processing method, and willingness to experiment. For some natural coffees, a brief wash can provide a clean slate to remove impurities without deteriorating inherent qualities. But the risks of losing flavors, encouraging mold, and altering chemistry should not be ignored. There is no universally right choice, only the option best suited to your needs and tastes as a roaster or barista. Carefully sample test washed vs natural batches to guide your practices.

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