What Happens if Coffee Is Ground Too Coarse?

Coarse grounds have become synonymous with moderation in coffee culture. When coffee beans are not ground to be powdery, they produce a mellower beverage with just enough caffeine. But moderation is lost if the grounds are too thick.

If coffee is ground too coarse, the resulting beverage is watery and doesn’t have enough caffeine. This is because the area that comes in contact with the brewing water is reduced when the ground size is increased.

In this article, you will learn why coarser grounds can produce watery coffee and what you can do to fix the weak coffee made from thick grounds. You will also learn different ways to get stronger coffee the next time you brew it, even if the grounds remain thick. But first, you need to understand the utility of grinding coffee beans.

Why Are Coffee Beans Ground?

According to some accounts, coffee beans were discovered when the whole berries were consumed by goats. This resulted in a burst of energy that got goat-herders curious about the fruit and eventually the berry. 

If we go by this story, then the beans were probably boiled whole first. But as time has passed, we have refined the art of coffeemaking and have eventually come to grinding the roasted beans in varying degrees of fineness.

This is because the extraction of the various elements in a coffee beverage is partially contingent on the size of the coffee grounds. Here we explore how keeping the grounds coarse affects the beverage and the brewing process.

When the Grounds Are Too Coarse, the Coffee Is Not Potent

Many people consume coffee as a ‘wake up’ beverage. It is a source of caffeine that makes one more alert and improves focus. The strength of the coffee usually refers to how much caffeine it has, and the finer the grounds are, the more caffeine there is in the resulting beverage. This is because coffee beans release caffeine into the environment or water through surface interaction.

When you cut a bean in two, you double its surfaces. Fine grounds have more surface area while coarse ground doesn’t. As a result, the coffee that is made with coarse grounds has less caffeine than the one made from fine grounds.

In very coarse grounds, the surface area is reduced so greatly that proper extraction is not possible. If your coffee consumption is for its caffeine utility, coffee made with impractically coarse grounds can leave you drowsy. Upon grinding a fresh batch of coffee beans, you should wait to brew a test cup to find out whether the beverage is potent.

After consuming the sample, you should wait an average of 15 minutes. In case you don’t feel the most alert, the coffee grounds might be too coarse. It is also possible that the brewing temperature is low, as that has a similar effect in decreasing the rate of extraction.

When the Grounds Are Too Coarse, the Coffee Can Be Watery

You might not even get through the test cup if the coffee is ground too coarse because you’ll immediately feel the difference in flavor. Coffee is more than just a cup of caffeine, and those who consume coffee for pleasure can enjoy how it tastes. There’s a key difference between how caffeine-lovers consume coffee and how coffee-lovers drink it. For caffeine lovers, stronger is always better.

But for coffee lovers, there is a point of intensity after which coffee concentration yields diminishing returns. Most people who enjoy the actual taste of coffee tend to lean towards mellower servings made from coarse grounds. Coffee made from larger grounds features fewer acidic oils and requires less sugar.

When the grounds are too coarse, though, the coffee comes out watery. Needless to say, it doesn’t taste too good. In some instances, extremely coarse grounds produce coffee that tastes like water used to rinse a coffee maker. The wateriness of coffee can be noticed by just looking at the cup. Again, a test cup is one of the best ways to find out if the grounds are too coarse. If the yield is visibly diluted, you can regrind the batch and aim for a finer result.

How to Fix Weak Coffee Made From Coarse Coffee Grounds?

You can fix weak coffee by rebrewing it with old grounds and increasing the brewing temperature. This results in a higher extraction rate, which offsets the naturally low extraction of extremely coarse coffee grounds.

The second option is for those who care more about caffeine than flavor. A pinch of instant coffee can add the missing punch to a cup of weak coffee. My article on rebrewing weak coffee features multiple methods of fixing an already brewed cup. But if you get your beans ground at the roastery and have brought home a bag of grounds that are too coarse, you want to fix the issue and not the symptoms.

How to Get Strong Coffee From Grounds That Are Too Coarse?

You can get stronger coffee from very coarse grounds by doing one of the following:

  • Increase brewing time – The longer the coffee grounds are in contact with hot water, the more flavor and caffeine they will extract. 
  • Increase brewing temperature – The higher the temperature at which you brew coffee, the deeper the extraction.
  • Brew the coffee twice – Instead of making it a one-time fix, you can start routinely brewing your coffee twice. It takes getting used to but is one of the lowest upfront-effort methods of making strong coffee with extremely coarse grounds.
  • Regrind coffee – You can regrind the coffee grounds in a spice grinder or even with a coffee mill to get them to a size where they produce decent coffee.

Final Thoughts

Coarse grounds generally produce coffee that has the broadest appeal thanks to moderate bitterness and decent opening notes. However, if one errs on the side of coarseness, the resulting beverage can be disappointingly watery with a lot less caffeine. Rebrewing the weak coffee with the same grounds can be one solution, but it is better to simply regrind the batch to an acceptable level.

Tim S.

Tim loves roasting, brewing, and experimenting with coffee. After years of perfecting this craft, working as a barista, and owning a small coffee service in college, he has decided to share his knowledge with the world.

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