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Can Cold Brew Coffee Mold? (Yes, so here’s what to do)

By: Author Jeff Campbell

Posted on  - Last updated:

Categories Coffee & Tea, Food Safety Tips

Cold Brew is one of the hottest (pun intended) trends in coffee right now. However, the process requires time and patience, and many prefer brewing it in bulk for a few weeks. So, this got me thinking can cold brew coffee mold?

Cold-brew coffee will mold if brewed at room temperature for more than 24 hours or not refrigerated after brewing. Also, it can mold inside the refrigerator if kept longer than 2 weeks. 

But how do you know if it’s gone bad? Does it need to be refrigerated? How long can it last at room temperature? How long is too long for letting it brew?

I’ll answer all of these questions and more.

Just keep reading!

Does cold brew coffee go bad?

Cold brew coffee will go bad if not consumed within 2 weeks of brewing. Do not brew at room temperature for more than 24 hours and refrigerate in a sealed container following brewing. Date the container and discard any remaining cold brew after 2 weeks.

Cold brew coffee is crafted by slowly steeping ground coffee in water for 12 to 24 hours. Once it’s ready, the grounds are strained from the liquid. This process produces a potent, flavorful cold brew concentrate with a shelf life of up to 2 weeks.

However, an even easier way to make cold brew coffee is with a specially designed coffee maker.

But just because it’s specially designed doesn’t mean that it costs an arm and a leg. Here’s one that is rated #1 on Amazon and is very reasonably priced. Just click that link to check the current price on Amazon.

While cold brew coffee does have a relatively long shelf life, it does go bad eventually. It may start to taste stale and eventually grow mold as well.

Cold-brew can last up to 14 days, but for the best flavor, it should be consumed within a week. Over time, it will get bitter, and you won’t want to drink it.

Homemade cold brew coffee is cheap, so if it’s been a week or more since it’s been brewed, just throw it out as it is better to make a new batch.

How do you know if cold brew has gone bad?

Cold brew coffee is starting to go bad when the following signs appear:

  1. It will start losing its aroma and flavor. There won’t be any telltale smell, but the flavor will begin to decay pretty rapidly.
  2. The flavor is diminished
  3. Eventually, it will have a bitter taste, and it just won’t taste terrific as usual.
  4. The acidity increases in the flavor
  5. The smell when opening the container is not pleasant
  6. Mold spores are noticeable on the surface

Overall, it shouldn’t be kept for longer than two weeks. Otherwise, you could fan the possibility of nasty bacterial growth.

As with any consumable, I always follow the mantra, “when in doubt, throw it out.” There’s no sense in getting sick because you’re unsure of whether your cold brew is still good enough.

Much longer than two weeks, and you may discover that your cold brew has begun to mold. You’ll know it’s molded when you see tiny little “islands” floating around in your coffee. You should definitely throw out anything that has mold growing on it.

If you like to experiment with coffee, or if you’re a low-carb, keto, or paleo dieter, you may wish to try Bulletproof coffee.

If you have never had it, many recipes say that you need to use grass-fed butter. Grass-fed butter is recommended because it’s higher in vitamin B, K2, and omega-3 fats.

But regular butter or ghee works just fine. Read this recent article to learn more.

Just click the link to read it on my site.

How long can cold brew last in the fridge?

Cold-brew concentrate should be stored in the refrigerator for not more than 14 days. And it will be freshest within the first 7 days. It should also be stored in a container with a lid to minimize exposure to oxygen.

A typical rule of thumb for most things edible is that products should not be stored any longer than two weeks.

The same goes for coffee as well. If you haven’t used all of your cold brew coffee within the first two weeks, just throw it out. I’d be surprised if you want to drink it after a week, honestly.

Using clean utensils and making sure your brewing system is clean and sterilized will help prolong the freshness of your cold brew coffee, as will using glass containers as opposed to plastic.

If you are a coffee lover, you may want to consider purchasing Fair Trade organic coffee.

All coffee offers a reduced risk of cardiovascular disease, type 2 diabetes, Parkinson’s disease, and gout, according to Harvard. However, the main benefits of organic coffee are coffee workers, land, and the environment.

To read more about how organic coffee helps workers and the environment, check out this recent article.

Just click the link to read it on my site.

Does cold brew go bad if not refrigerated?

Cold brew coffee will go bad within 48 hours if kept unrefrigerated. But the flavor will begin to diminish after 24 hours if kept unrefrigerated.

For optimal freshness, and to prevent bacterial growth, cold brew really should be refrigerated. However, if you don’t want to refrigerate it, or will be traveling, it’s fine to keep it at room temperature, but for a short amount of time.

After about 24 hours, though, the aromatics will start to dissipate, which also impacts the flavor.

You also want to ensure that when you drink it, you are pouring it into a separate container. Don’t just drink it out of the container you used for brewing or storing it. Doing so might introduce new bacteria from your mouth and cause it to go bad faster.

If you like, you can even heat up your cold brew. While it may affect the taste slightly, there is no risk of drinking a cold brew coffee at higher temperatures.

However, do not microwave it. The best way to heat cold brew coffee is by adding boiling water. You may also reheat it on the stove, without overheating it, or it may develop a burnt or bitter taste.

To read more about how to heat your cold brew, read this recent article.

Just click the link to read it on my site.

How long does it take for mold to grow in cold brew coffee?

Cold brew coffee will begin to mold after 2 weeks of being kept in refrigeration. Additionally, it can begin to mold within 48-72 hours if kept unrefrigerated.

Just like other food items, cold brew is also perishable. However, it should stay fresh for up to two weeks if stored in an airtight container in the fridge.

Yet, how quickly the mold grows in your cold brew will depend on several factors, not just refrigerator temperature.

When brewing your cold brew, make sure all of your utensils, dishes, and ingredients are clean and dry. You may also consider storing your grounds and cold brew in glass containers. Plastic containers, even clean ones, can potentially hold bacteria that contribute to growth.

You should also sterilize your containers and brewing system every so often.

By maintaining a clean environment and ensuring your brewing system is sterilized, you will prolong any potential bacterial growth.

In case you are wondering if you should use distilled (or boiled) water to make your cold brew. Unfortunately, it also removes beneficial minerals that enhance the flavor. And for some coffee maker brands, it can also speed up the corrosion of the internal parts.

To read more about why distilled water may not be the best choice for your coffee, read my recent article.

Just click the link to read it on my site.

Final Thoughts

In this article, I covered all the things related to keeping your cold brew coffee fresh, and I hope all your doubts are clear. Besides, now you know that it won’t last beyond 24 hours if not refrigerated, and how to tell when it is unfit to drink.

Though its life can be extended with proper storage and refrigeration, Cold Brew Coffee, much like other beverages, doesn’t have a very long shelf life. Unfortunately, once it starts to stale, it will lose flavor quickly.

So if you take care of the storage instructions, your cold brew will stay fresh and crisp till the last drop.

Photos which require attribution:

Galaxies by Quinn Dombrowski is licensed under CC2.0

As an Amazon Associate I may earn a small commission from qualifying purchases if you click to Amazon from my site and choose to make a purchase. You can read my complete affiliate disclosure for more details.

Jeff Campbell
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