Is It Safe To Grind Wet Coffee Beans?


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Is It Safe To Grind Wet Coffee Beans?

Grinding your coffee engages the senses and allows you to customize your grind according to your chosen beverage. Under ideal conditions, this part of the process takes very little time. However, if your beans are wet, can you still grind them? 

It is unsafe to grind wet coffee beans in a grinder because wet beans will grind unevenly and clog the grinder. It will also introduce liquid into an otherwise dry area, promoting mold growth. However, a tiny amount of water added to the hopper can improve the grind and eliminate static cling.

In what follows, we will cover why grinding wet beans won’t work very well. We’ll also discuss how beans get wet in the first place, when you’d want to use wet beans, and how to dry out the beans when you don’t.

Coffee Beans’ Appearance Relative to Their Roast Level

Before we launch an exploration into the vast, beany ocean, we should first figure out what we mean when we say the beans are “wet.” 

Were you running and tossing them to yourself, and they ker-splashed into a puddle? 

Hey, we’ve all been there. 

However, unless you somehow made them wet on the outside with water, they may just be oily, which can give coffee beans a wet look.

If you have dark roast beans and you’re sure you didn’t take them swimming, then they just have an oil coating. Check by rubbing a couple of beans between your fingers. If it looks, feels, and walks like oil, then it’s just oil, and you don’t have to worry about it. 

Keep the beans fresh in a sturdy, airtight container away from light and heat and grind what you need as you go.

If you truly have wet beans, then keep reading.

Grinding Wet Coffee Beans Clogs the Grinder

Let’s say you’re in an experimental mood and want to see what happens if you roll the dice and grind up some wet beans in your electric burr grinder.

According to experienced baristas, doing so will end up clogging up your grinder. You don’t want to do this. 

If your grinder clogs, you must take it apart and clear everything out. What began as a plan to grind some beans will become an extensive cleaning and maintenance session. You just wanted a cup of coffee! 

Grinders are designed to grind dry beans with a certain amount of resistance and cellular give. Water changes the beans, so the grinder can’t achieve the same grind size because the material is too thick and doesn’t break apart cleanly like dry material.

A clogged grinder can also ruin the appliance because it’s not made to have that much moisture inside, especially in an electric version. The water could cause a short or induce rusting and corrosion.

As if all this wasn’t enough, clogging the grinder could also force larger chunks between the burrs, wrenching them off track. You might then have to watch a bunch of YouTube videos to learn all about grinder repair.

Suppose the patron saint of coffee performs a miracle, and your grinder survives the tortuous wet grind. Now you have a gritty coffee paste, which might prove rather difficult to imbibe unless that was your goal.

If you still need to grind some wet beans to make a paste for a cake or frosting recipe, I suggest using a mortar and pestle. The beans won’t clog. You can also evaluate the entire process, grinding finer if you so desire. 

For faster wet grinding, opt for a food processor or an appliance that handles wet ingredients. 

Frozen Beans Can Create Moisture

Many people keep their coffee beans in the freezer to maintain freshness, which works well when storing beans for longer periods. 

When thawing coffee beans from freezer storage, use the refrigerator to stave off condensation. 

However, when thawing them from short-term storage in the freezer, the frozen coffee beans typically hit the warmer kitchen air and condense, forming water beads on the surface. 

This clumps grounds together and causes uneven grind consistency, adversely affecting flavor and texture. It also wastes coffee beans unless you risk re-grinding, which can clog your grinder further.

You never want to store wet beans or wet grounds. Wet grounds can turn moldy in a matter of days. Wet beans can also turn moldy, especially in a closed environment where the moisture can’t escape well.

Read this article from the National Coffee Association for more on proper bean storage.

The Best Way To Dry Wet Coffee Beans

To dry out coffee beans, you need a quick, controllable, and effective method. It’s important to understand that large amounts of water-soaked beans might prove too far gone to rescue, in which case you’re better off composting them.

But even if the exposure was minimal, bacteria and water minerals will completely change how the coffee tastes. Not to mention the oxidation that occurs while gathering, drying, and storing them.

Drying Methods That Don’t Work As Well

Here are some not so good ways to dry your wet coffee beans: 

  • Drying out wet coffee beans in the sun. This won’t work very well and takes a long time. It also exposes the beans to air for a prolonged time, such that what you gain with dryness, gets lost in taste and aroma. 
  • Running wet coffee beans through a microwave or oven stint. This will also take a while and might cook or overdry the beans, which ruins the flavor.
  • Using an air fryer. This might do the trick, but the beans won’t be stirred, and you can’t control airflow or heat proximity. 
  • Using a kitchen torch (like you would roast your own beans). You could try this but you risk burning, over-roasting, or over-drying the beans. 

Your Best Bet Is To Use a Hair Dryer 

A hair dryer lets you control the force, temperature, and the heat’s focus much better than using passive methods. And since open air makes beans go stale faster, you’ll want to work fast and in small batches. 

  1. Pat the beans in a kitchen towel to remove the standing moisture. Keep them nearby (in the towel) as you work, ensuring you have time to dry them all out in one sitting. 
  2. Set a large heat-resistant bowl on the counter, sized according to how many beans you need to dry, plus room to stir with a utensil. 
  3. Pour your beans into the bowl and start the hairdryer on warm and in the lowest wind-force setting. 
  4. Focus the heat around the bowl’s interior, moving the hairdryer around in a circular manner. (You may need to hold the hairdryer up a bit from the bowl, so it doesn’t blow the beans all over the place.) 
  5. Stir the beans while continuing to move the hairdryer around. You’ll notice the water evaporating, uncovering the natural oils underneath. 
  6. Remove your dry beans to an airtight container if you aren’t grinding them immediately. You should use them as soon as possible because they’ve been exposed to so many taste-altering conditions.  

Note: If the beans turn a dark roast and look devoid of oil after drying, it may indicate they are saturated. This means they won’t taste right and have become compost material. 

Some Moisture Is Helpful

Not all moisture proves detrimental to your coffee beans or grinder. This we know because moisture moves in and out of the air unless you grind in a vacuum. 

Some grinders even come with a water-spraying accessory to mist your beans in the hopper. This helps remove the static in the air that causes the grounds to cling to everything. 

Spraying can help with larger amounts of beans, but it could overwet them, leading to some of the above-mentioned problems. If using a sprayer, start with as few beans as possible and work your way up from there. 

To prevent static, use a tiny amount of water. You may experiment with different amounts to achieve the desired effect but only increase by a drop or two at a time.

Check out this clever and super simple hack by French Press Coffee. It shows how to eliminate static in the hopper and grounds container dosing drops via a paper towel:

Notice how he uses very little water, such that it does not coat the coffee beans. 

Nevertheless, you might not see the same results with your setup. Cooks Illustrated did not succeed with the water technique but found that simply waiting a while allowed the static to clear out on its own. You can check out their method here.

If you don’t have a grinder, grinding coffee and espresso beans might be challenging, but there are several ways to do it. But that doesn’t mean you’re out of options. Click on the link to read my in-depth guide on grinding coffee beans without a grinder. [How to Grind Coffee and Espresso Beans Without a Grinder]


Wet grinding won’t work the way you think unless your goal is coffee paste and your grinder a mortar and pestle. Using any other grinder on wet coffee beans guarantees a mess and bad-tasting coffee. And that’s if it doesn’t ruin your grinder.

If you need to save the beans, you can unless they’ve been saturated with water. If not, and there’s only a little water, you can still bring them to a grindable state, but the coffee won’t smell or taste as good as fresh coffee beans.