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Coffee Basics

Can You Reuse Coffee Grounds to Make More Than One Cup of Coffee?

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Coffee grounds that have been reused to make a cup of coffee

With the price of almost everything rising these days, if you’re like most people, you’re looking for ways to save money wherever possible.

While making your coffee at home versus stopping off at a local coffee shop is a great place to start, buying quality coffee beans can still add up. 

This then begs the question, can you reuse coffee grounds to brew more than one cup of coffee?

You might be surprised to learn that, technically, you can. However, there are a few important factors you should consider before going down this path.

Can You Reuse Coffee Grounds?

Despite what you may have heard, spent coffee grounds can be reused to brew more than one cup of coffee. 

However, once used, spent coffee grounds are much more susceptible to bacteria and mold growth. Because of this, it’s best to reuse spent coffee grounds on the same day as their initial brew. 

If the plan is to reuse the grounds at a later date, it’s critical that they’re thoroughly dried, stored in an airtight container, and kept in a dark, dry, cool place. This will ensure your second cup is safe and provides the most flavor possible.

What Happens When You Reuse Coffee Grounds?

Although it’s safe to reuse coffee grounds, that doesn’t mean the resulting cups of coffee will be of the same quality as the first. 

Two main things happen to coffee grounds after their initial use:

1. Diminished Flavor

Coffee beans contain various oils and other organic compounds that are extracted during the brewing process. These elements are what give your cup of coffee its distinctive flavor and aroma, as well as contribute to its many health benefits.

When coffee grounds are reused, the extraction process is far less effective due to most of the coffee’s compounds having already been dissolved in the first brew. This results in an under-extracted and often flat or sour-tasting cup of coffee.

2. Less Caffeine

The majority of a coffee’s caffeine will also be extracted during the initial brewing process, with subsequent brews having a much lower caffeine content.

On average, fresh coffee grounds contain 10 to 12 mg of caffeine per gram. In contrast, spent coffee grounds can range anywhere from 3.59 to 8.09 mg

Although used coffee grounds won’t provide the same level of caffeine as their freshly ground counterparts, the good news is there’s still enough to provide you with a little afternoon “pick-me-up.”

Should You Reuse Coffee Grounds?

While you absolutely can reuse coffee grounds to make a second cup of coffee, the bigger and more important question is, should you?

Much like determining which roast level is best, the answer to this question ultimately comes down to personal preference.

To help make answering it a little easier, we decided to test three different brewing methods to see how reusing coffee grounds actually affected the resulting brew.

When testing a particular brewing method, we made sure to use the same coffee-to-water ratio, brewing temperature, and brewing time for each brew.

Additionally, we also provided three different perspectives when sampling the brews:

  • Me: Someone who’s a bit of a coffee snob and enjoys a strong cup of black coffee.
  • My wife: Someone who appreciates black coffee but prefers it on the milder side.
  • My 11-year-old son: Someone who doesn’t like coffee.

Here’s what we discovered:

Test #1: Auto-Drip

Comparison of auto-drip coffee brewed with fresh and reused coffee grounds
Filtered Grounds/Kristin Van Gerpen

Color

Of the three methods tested, the auto-drip had the biggest change in color, looking almost tea-like in the second brew.

Aroma

While there was a slight difference in aroma between the two brews, it was negligible at best and likely wouldn’t be noticed by most coffee drinkers.

Flavor

  • Me: I thought the second brew tasted horrible. Not only was it flat, but it had a slightly sour taste. While adding a teaspoon of flavored creamer did mask the sourness, it didn’t improve the overall flavor of the coffee.
  • My wife: While she didn’t think the second brew was great, she also didn’t think it was horrible.
  • My 11-year-old son: As expected, he hated the first brew but didn’t mind the second. Once the flavored creamer was added, his enjoyment jumped significantly.

Test #2: French Press

Comparison of French press coffee brewed with fresh and reused coffee grounds
Filtered Grounds/Kristin Van Gerpen

Color

While the French press did produce a lighter-colored brew on the second go around, it wasn’t nearly as significant as in the other two methods.

Aroma

There was no noticeable difference in aroma between the two brews.

Flavor

  • Me: The second brew was flat and lacked the robust, full-bodied flavor the French press is known for. While I definitely didn’t like it, it wasn’t nearly as bad as the auto-drip.
  • My wife: She didn’t think the second brew tasted all that bad and mentioned that she might even like it a little better than the first brew.
  • My 11-year-old son: He absolutely loved the second brew, especially when we added a teaspoon of flavored creamer. He kept asking if he could have his own full-sized cup.

Test #3: Cold Brew

Comparison of cold brew coffee brewed with fresh and reused coffee grounds
Filtered Grounds/Kristin Van Gerpen

Color

Although not quite as significant as with the auto-drip, the cold brew also produced a big drop-off in color from the first brew to the second.

Aroma

While you could still detect the aroma in the second brew, it was noticeably weaker than in the first.

Flavor

  • Me: The second brew was almost completely flavorless. I had to really focus to perceive the little bit of taste that was present. Even the cold brew concentrate by itself (before diluting it with equal parts water) was still very flat and weak-tasting.
  • My wife: Agreed with my assessment.
  • My 11-year-old son: While he didn’t dislike the second brew (both diluted and concentrate-only versions), he definitely preferred the first brew.

The Verdict

Don’t do it!

Always use freshly ground beans each and every time you brew a cup of coffee.

In our opinion, there are only two reasons ever to consider reusing coffee grounds:

  1. Your child wants to try coffee, and you’d like to soften the intensity of its flavor and/or reduce the level of caffeine.
  2. You’re all out of coffee beans, but you REALLY need that second cup and are willing to deal with a significant loss of flavor.

Final Thoughts

Although reusing coffee grounds can be cost-effective, it’s not without its downsides. And while our experience with this practice wasn’t all that enjoyable, you may have a completely different opinion. Because of this, we encourage you to experiment and find out for yourself.

Lastly, if you’d like to continue furthering your coffee knowledge or if you’re looking for ways to improve your home barista skills, be sure to check out the brewing guides and coffee basics sections of our website. 

Frequently Asked Questions

While we always recommend using fresh coffee grounds when you brew a new cup, if you do choose to reuse your coffee grounds, it’s best to do so only once after the initial use. Reusing them more than once will lead to a significant drop in both the flavor and caffeine content of the coffee.

Technically, yes. However, similar to other brewing methods, most of the coffee’s flavor and caffeine are extracted in the first shot. A second shot using the same grounds will be noticeably weaker and lack the rich flavor profile espresso is known for.

Reusing coffee grounds is generally considered to be safe and unlikely to make you sick as long as they’re used within a short period of time (ideally the same day). However, when left out for too long or not stored correctly, they can become a breeding ground for bacteria and mold, posing a potential health risk.

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AUTHOR

Hey there! I'm Michael, founder and editor-in-chief of Filtered Grounds. In addition to being an entrepreneur, I'm also a bit of an endurance sports junkie. Whether it's working toward my business goals or training for my next Half Ironman triathlon, a good cold brew or cup of French press plays a role in fueling my performance.