How Long do Coffee Grounds Last- University Study

Ask any coffee enthusiast about how they start their day, and chances are they will most certainly tell you their day starts with a cup of coffee. Brewing the perfect cup of coffee is also high on their daily agenda, and part of being able to prepare the cup of coffee is knowing how to preserve the coffee grounds they plan to use on their coffee.

Unfortunately for many coffee brewers, the number of days, months or years it takes to store coffee grounds before they go bad is foreign to them. There is also confusion on whether coffee grounds go bad or become stale.

So, how long do coffee grounds last? Coffee grounds will last just one week at a room temperature of seventy-two degrees Fahrenheit. After one week, the coffee made from one week old grounds has a bitter taste when compared to coffee that is prepared from freshly ground coffee.

Dr Carolyn Ross, department of Food Science and Human nutrition at Washington University performed tests on ground coffee to test the freshness and she concluded that bitterness occurs in ground coffee after just a week. Nevertheless, it keeps its freshness longer if refrigerated.

Do coffee grounds go bad?

Most coffee grounds’ original packaging has no expiry dates. However, they have a “best by” or “best before” date. This is because coffee grounds can go stale and lose their freshness.

A closer look at their packaging also shows that they have a small hole meant to allow coffee grounds to go through the degassing process that involves releasing carbon dioxide from the coffee grounds. Once carbon dioxide is released, it escapes through the package openings, and coffee grounds start absorbing oxygen, a process that marks the beginning of coffee grounds losing their fresh flavor.

Once grinding is done, most coffee grounds stay fresh for one week, and then they start going stale.

This is a problem for most coffee brewers who prefer to grind their coffee once and then store the surplus for future use to save time. The downside is, after a week, the quality of coffee prepared using ground coffee begins to deteriorate, and the original flavor is also lost.

Coffee grounds also have one of the highest rates of degassing; hence it is always recommended to grind only the amount you need when brewing your coffee.

Freshly brewed coffee also has a short lifespan before it starts going bad. For coffee brewed from coffee grounds, it only takes 30 minutes before it loses its taste and becomes stale. After four hours, the freshly brewed coffee starts to turn acidic. While you can still drink coffee at this point, it is not recommended to drink the coffee 24 hours after brewing.

How long can you keep ground coffee for?

As stated above, coffee grounds do not have an expiry date and can be stored for years before going bad.

Coffee grounds are sold in airtight packages and can last between three to five months if they are unopened and stored in a dry storage area.

If stored in a freezer, a bag of airtight unopened coffee grounds can last for up to two years while still being able to maintain the level of freshness you would expect when brewing coffee. This is because the freezer provides an environment that reduces degassing, hence slowing down the rate at which coffee grounds go stale.

However, after buying an airtight bag of coffee, chances are you start by opening the bag and grinding the grounds for your coffee. Some coffee brewers prefer to grind all the coffee grounds simultaneously to save time, while others prefer grinding their coffee in lesser amounts. Whichever method you choose, opening the airtight coffee grounds package reduces their freshness lifetime.

For coffee brewers who prefer to grind their coffee in tiny amounts and leave the coffee grounds in their respective packages, for the next time they decide to brew coffee, the remaining coffee grounds take a week or two to stale from the moment they are opened. Storing the coffee grounds in the freezer increases the time between one to five months.

However, if coffee grounds are grinded and stored, they take just a few days before they lose their freshness. In most cases, the grinded coffee grounds do not even last a week before they start deteriorating and become stale.

Fortunately, in most houses that brew coffee regularly, a bag of coffee grounds does not last that long.

How do you know if coffee grounds have gone bad?

On average, the shelf life of coffee grounds is 3 to 5 months at room temperature when they are sealed and about a week or two when they are opened.

Therefore, like most staples in your kitchen, coffee grounds can also go bad, and a closer examination of their packages makes it clear that they have a sell-by date indicating when to use them.

However, your coffee grounds can go bad before the date indicated on your packaging without you knowing. When this happens, it raises the question of whether it is safe to consume the coffee grounds past their prime and what impact they have on your health.

Unfortunately, when coffee grounds go bad, your eyes will not be able to spot any difference because the physical appearance of the coffee grounds stays the same. Your next bet is to smell the coffee if you have doubts that it may have gone bad.

Avid coffee brewers will tell you that freshly brewed coffee has a strong pleasant caramel-like fragrance. However, the strong caramel-like fragrance disappears when coffee is brewed from stale coffee grounds. This is because coffee grounds are made of oils, which are degraded once the coffee grounds start going stale. This causes the coffee to start having a dusty ashtray-like scent that your nose can easily detect.

Avid coffee brewers also know how their daily coffee should taste and can easily detect a change in taste. When coffee grounds start to go bad, they also lose taste and become rancid or super sour. This is also an indication that your coffee grounds have gone bad.

Unfortunately, people who do not regularly take coffee cannot pick the change in smell and taste and hence can continue consuming coffee grounds that have gone bad. This, however, has no impact on the health of drinkers because consuming coffee that has been brewed from rancid coffee grounds has no impact on people’s health. In fact, consuming coffee past their sell-by date is mostly safe.

In a few cases, coffee grounds can show signs of going stale by developing molds. This is mostly true when the coffee grounds are stored in a moist area or an area where moisture can invade. In such cases, it is recommended that you discard the coffee.

Here is an interesting video for you that discusses how long brewed coffee lasts. Is it just a few hours until the taste is altered? A few minutes?

drinking old coffee, would you do it?

How long does ground coffee last in the fridge?

One of the most used methods for storing coffee grounds is a freezer. Normally, an unopened coffee ground package can stay in dry storage for three to five months after the sell-by date without going bad, and one to two weeks if they are opened.

On the other hand, freezers can extend the lifespan of coffee grounds, extending longevity for up to two years before the coffee grounds start to go stale when they are unopened and up to five months for opened coffee grounds.

Brewed coffee grounds can also stay in a freezer and last longer than the recommended four hours without going bad.

However, storing your coffee grounds in the freezer can result in them being freezer burned, which can accelerate the rate at which they go stale. This can be prevented by:

  1. Ensuring that your coffee grounds are stored in the deep freezer instead of your fridge’s freezer because chances are, it is the least most used part of your fridge; therefore, it is not opened often.
  2. Store your coffee grounds on their original packaging. Using plastic bags and paper can also accelerate the stale process.
  3. Only store the coffee grounds for less than two weeks. Extending this duration will result in your coffee beans going stale. Also, ensure that they are in an airtight container during the two-week duration to avoid degassing and freezer burn.
  4. In cases where you have taken out extra coffee grounds for grinding, do not return the excess coffee grounds because they can contaminate the remaining ones.

How to store ground coffee long term

Coffee grounds can stay fresh for up to two years. This is dependent on the methods used for preservation and how long a coffee brewer needs their coffee grounds to stay fresh. Below are some of the most common methods that you can use to keep store coffee grounds for the long term.

  • Freezer for long term storage of coffee

This is the most commonly used method of coffee storage for people looking to store their coffee grounds for more than a year.

The method involves placing your coffee grounds in a freezer and only opening to retrieve coffee grounds for your personal use only when preparing coffee.

In the freezer, you can expect a bag of unopened coffee grounds to last for up to two years while still maintaining their freshness. However, if the original coffee ground is opened and stored in the freezer, you can expect between one to five months before the coffee grounds start to go stale.

However, coffee grounds stored in a freezer can suffer freezer burns due to improper storage inside the freezer. This can reduce the amount of time these coffee grounds can stay fresh.

Also, if the container used to store the coffee grounds is not air-tight, chances are the degassing process will increase, which can lead to your grounds becoming stale faster than expected.

  • Dark, dry storage area for storing coffee for prolonged periods of time

You can also store your coffee grounds in a dark, dry storage area. When the coffee grounds are in their original airtight package, they can last between three to five months in a dark, dry storage area.

However, when the package is opened and stored in a dark, dry storage area, it only lasts a week or two before going stale.

How do you store coffee for years?

Contrary to common belief, coffee can go bad. This is because they are made of oils, which can encounter oxygen, get oxidized, and turn the coffee to rancid.

Fortunately, coffee grounds and other types of coffee take time before going rancid. However, if the coffee grounds are stored properly, they may start losing their original taste.

It is also important to note that diverse types of coffee last differently. For instance, coffee grounds only stay fresh for 5 months after best by date, roasted coffee beans last for up to two years, instant coffee can take up to 10 years before they go bad and green coffee beans can last up to 5 years when unopened and at least a year when opened.

Here is a table that represents how actual coffee drinkers can store their coffee for years:

How are you able to store your coffee for numerous years?Percentage of total responses
Buy unroasted coffee beans that are green and vacuum seal them so that oxygen will not cause them to deteriorate. To roast your coffee beans, I recommend the Fresh Roast SR540, click to see the current pricing for yourself on Amazon. 8%
Purchase the glass jars of instant coffee. Unopened, they will be ok for years. 25%
Loading up on coffee that has been freeze dried. This format will last a lot longer than canned coffee. Just make sure not to open the packaging before storing for the long term. 22%
Many forum commenters state that they buy Folger’s coffee in a can. They claim that even after 15 years, this coffee will still be drinkable. 45%

Below are some of the proven ways you can store coffee if you want it to last for years.

  • Freezer

Coffee has little moisture, and hence it is not easily freezer burned. This makes it perfect for storage in freezers.

  • Airtight containers

Once opened, coffee can go from fresh to stale fast. To prevent this, you should consider storing your coffee in a dry airtight container. I recommend the Coffee Gator Stainless Steel Coffee Grounds and Coffee beans Container. It is available on Amazon, click to view the current pricing.

  • Vacuum sealing

Oxidation is among the major factors contributing to coffee going bad. To prevent this, best-quality coffee comes packaged in a vacuumed sealed container. This is helpful in preventing air inside the container.

One thing to note is that coffee grounds and coffee beans have air inside, and in vacuum sealing, this air is not removed. Instead, the air around the coffee is vacuumed out. The bags are also semi-porous, and hence the coffee aroma can also escape from the container.

  • Oxygen absorbers

You can decide to put oxygen absorbers inside your coffee containers. Air absorber is iron that grapes oxygen molecules in containers, hence preventing the process of oxidation. They can remove any trace of oxygen, hence keeping the coffee fresh.

Coffee Questions

It is hard to decide on how much coffee to use. For instance, how much coffee per cup is a good query.

Aron Blake

I am the lead copywriter on Homezesty and the Webmaster. I have a lot of experience in home renovations and the creation of style. I enjoy writing and sharing my tips on how to create the best living environment. My Linkedin Profile, My Twitter Account

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