How Long Does Cold Brew Coffee Last? A Complete Guide

I love cold brew coffee both for the smooth flavor and the convenience. With just one batch, you can enjoy delicious iced coffee for days on end, a true convenience for any caffeine lover. But how long does cold brew coffee last? How long can you savor your coffee before it loses its luster or even becomes dangerous to drink? I’ll cover all of that and more in this article.

What’s the Shelf Life of Cold Brew Coffee?

The typical shelf life of homemade cold brew coffee is generally accepted to be around 14 days when stored in the refrigerator. However, as a cold brew connoisseur, I personally don’t let mine linger for more than 5 to 7 days. After the 14-day mark, the risk of bacterial growth increases, potentially rendering your cold brew unsafe for consumption. But even before that, the flavor starts to deteriorate gradually.

One of the primary reasons for the flavor degradation in cold brew is oxidation. The coffee oils and compounds that contribute to the rich, nuanced flavors we all love are highly susceptible to oxidation when exposed to air. As the cold brew sits, more and more air comes into contact with the liquid, causing these delicate compounds to break down and lose their potency.

Additionally, cold brew coffee is a breeding ground for microorganisms, particularly after a few days of storage. While refrigeration helps slow down their growth, it doesn’t entirely prevent it. As bacteria and molds proliferate, they can produce off-flavors and potentially harmful byproducts, compromising both the taste and safety of your cold brew.

In my experience, the flavor of cold brew coffee starts to decline noticeably at around the 5 to 7 day mark in the fridge. The once vibrant and nuanced notes gradually give way to a flat, lifeless profile.

So, while the 14-day mark is generally considered the absolute limit for safety, I recommend aiming to consume your cold brew within the first 5 days for optimal flavor. And, of course, never push past 10 to 14 days, as the risk of bacterial growth becomes too high at that point.

What Affects the Shelf Life of Cold Brew Coffee?

There are a few factors that can influence how long your brew remains fresh and safe to drink.

Oxygen

Oxygen is perhaps the most significant enemy when it comes to preserving the flavor and integrity of cold brew coffee. As mentioned earlier, the compounds responsible for the rich, nuanced flavors in coffee are highly susceptible to oxidation. When cold brew is exposed to air, these compounds begin to break down, leading to a loss of aroma, depth, and overall flavor quality.

The oxidation process is a complex chemical reaction that occurs when oxygen molecules interact with the volatile compounds in coffee. These compounds, known as organic acids, phenols, and aldehydes, are responsible for the balanced flavors we associate with a well-crafted cold brew. As they oxidize, they lose their potency and can even produce unpleasant off-flavors.

Oxidation can also contribute to the growth of harmful microorganisms in your cold brew. Oxygen provides an environment conducive to the proliferation of certain bacteria and molds, which can not only affect the taste but also pose potential health risks if consumed.

To minimize the impact of oxygen on your cold brew’s shelf life, it’s crucial to limit its exposure as much as possible. This can be achieved by storing your cold brew in an airtight container and ensuring minimal headspace (the amount of air between the liquid and the lid). Whenever you pour a serving, try to use a container with a narrow opening to minimize air exposure.

Light

While oxygen is the primary culprit in the degradation of cold brew coffee, light can also play a significant role in compromising its flavor and quality. Just as sunlight can cause fabrics and furniture to fade over time, it can also have a detrimental effect on the delicate compounds that give cold brew its distinct taste.

Light, particularly in the visible and ultraviolet spectrum, can initiate a process called photodegradation. This process involves the breaking down of organic compounds, including those responsible for the aroma and flavor of coffee, due to the energy imparted by light waves.

The compounds most susceptible to photodegradation in cold brew coffee are the chlorogenic acids and quinides, which contribute to the brew’s acidity and bitterness. As these compounds break down, the cold brew can lose its characteristic brightness and complexity, resulting in a flatter, less vibrant taste.

Additionally, light exposure can also accelerate the oxidation process, compounding the flavor degradation caused by oxygen alone. The energy from light waves can initiate or catalyze oxidation reactions, leading to a more rapid breakdown of the delicate flavor compounds.

To protect your cold brew from the effects of light, it’s best to store it in an opaque or tinted container that blocks out visible and ultraviolet light. Alternatively, you can keep your cold brew in a cool, dark place, such as a pantry or cabinet, away from direct sunlight or artificial lighting.

Temperature

Temperature is another crucial factor that can significantly affect the shelf life and safety of your cold brew coffee. While refrigeration is generally recommended for storage, it’s essential to maintain the right temperature range to preserve flavor and prevent bacterial growth.

When it comes to flavor preservation, cold temperatures help slow down the oxidation and photodegradation processes that contribute to flavor loss. By keeping your cold brew chilled, you can reduce the rate at which these detrimental reactions occur, effectively extending the period during which your brew retains its optimal taste.

However, it’s important to note that extremely low temperatures, such as those found in freezers, can also have an adverse effect on the flavor. The freezing process can cause ice crystals to form, which can disrupt the delicate balance of compounds responsible for the cold brew’s taste profile.

On the other hand, warmer temperatures can create an environment conducive to the growth of harmful bacteria and molds. Most foodborne pathogens thrive in the temperature range between 40 degrees (F) and 140 degrees (F), known as the “Danger Zone.” If your cold brew is stored within this temperature range for an extended period, it can become a breeding ground for microorganisms, potentially leading to food poisoning or other health issues.

To strike the right balance, it’s recommended to store your cold brew coffee in the refrigerator, ideally between 35 degrees (F) and 38 degrees (F). This temperature range helps slow down oxidation and photodegradation while avoiding crystallization and also inhibiting the growth of most harmful bacteria.

How Do You Know When Cold Brew Is No Longer Safe to Drink?

Despite your best efforts to preserve your cold brew coffee, there will come a time when it’s no longer suitable for consumption. Recognizing the signs that your brew has gone bad is helpful to avoid potential health risks. Let’s talk about some telltale indicators to watch out for.

Change in Smell

One of the most reliable ways to determine if your cold brew coffee has gone bad is by paying attention to its aroma. Fresh cold brew should have a rich, inviting coffee smell, often with hints of chocolate, caramel, or other notes depending on the beans used. However, as it spoils, the aroma can change dramatically.

If your cold brew emits a sour, vinegar-like odor, it’s a clear sign that fermentation has occurred due to bacterial growth. This pungent, acidic smell is a telltale sign that your brew has gone beyond its safe shelf life and should be discarded immediately.

Another concerning odor to watch out for is a musty, earthy scent, which could indicate the presence of mold. Mold can not only produce unpleasant aromas but can also release mycotoxins, which are harmful substances that can cause sickness if ingested.

In some cases, you may notice a distinct rotten or putrid smell, similar to spoiled meat or eggs. This foul odor suggests that your cold brew has undergone significant bacterial growth and should be considered unsafe for consumption.

Visual Mold Growth

One obvious sign that your cold brew has gone bad is the appearance of mold growth on the surface or along the sides of the container. Mold can appear as fuzzy, discolored patches or spots, often in shades of green, black, or white. Even a small amount of visible mold should be taken as a clear warning sign that your brew is no longer safe to consume.

In some cases, you may also notice a cloudy or murky appearance in your cold brew, which could be a sign of bacterial growth. While freshly brewed cold brew can have a slightly hazy appearance due to the presence of oils and sediment, a thick, opaque cloudiness is a cause for concern.

It’s important to note that some bacterial growth may not be immediately visible to the naked eye, making it even more crucial to pay attention to other signs, such as changes in aroma or flavor.

It Tastes Off

Of course, one of the most reliable signs of cold brew going bad is its taste. A fresh, well-made cold brew should have a smooth, rich flavor with notes of chocolate, caramel, and a bit of fruitiness, depending on the beans used. However, as it spoils, the taste can change drastically.

If your cold brew has a sour or vinegar-like flavor, then fermentation has occurred due to bacterial growth. This acidic taste is often accompanied by a pungent, unpleasant aroma and confirms that your coffee has gone bad.

Another telltale sign of spoilage is a musty, earthy, or moldy flavor, which could be a result of mold growth.

In some cases, you may also notice a rotten or putrid taste, similar to spoiled meat or eggs. This foul flavor is means that there has been some bacterial growth, and your coffee isn’t safe to drink.

It’s important to trust your taste buds and discard any cold brew that has an off-putting or unusual flavor, as it’s likely a sign that it has gone bad and could potentially make you ill if consumed.

How Should You Store Cold Brew Coffee for a Longer Shelf Life?

Now that you understand the factors that can affect the shelf life of your cold brew coffee, let’s explore some practical tips and strategies to help you maximize its longevity and ensure you can enjoy every sip at its best. By following these storage guidelines, you can extend the freshness and safety of your brew, allowing you to savor it for longer without compromising on quality.

Use an Airtight Container

One of the most effective ways to prolong the shelf life of your cold brew coffee is to store it in an airtight container. As we’ve discussed, exposure to oxygen is a major contributor to flavor degradation and the potential growth of harmful microorganisms.

An airtight container limits the amount of air that comes into contact with your cold brew, slowing down the oxidation process and reducing the risk of bacterial or mold growth. Look for containers made of glass or food-grade plastic with tight-fitting lids that create a secure seal.

When transferring your cold brew from the brewing vessel to the storage container, minimize the amount of headspace as much as possible. The less air present, the better your cold brew will be protected from oxidation.

If you’re reusing a container, make sure to clean and dry it thoroughly before adding your fresh batch of cold brew. Any residual moisture or organic matter can provide a breeding ground for bacteria and mold.

Keep It Away From Light

To preserve the rich, nuanced flavors of your cold brew, store it in a cool, dark place, away from direct sunlight or artificial lighting. Opaque or tinted containers are ideal.

If you must store your cold brew in a transparent container, consider wrapping it in aluminum foil or placing it inside a dark box or cooler to shield it from light. Even indirect or ambient light can contribute to flavor degradation over time.

Don’t Use a Metal Container

While metal containers may seem like a convenient option for storing cold brew coffee, it’s generally recommended to avoid them, especially for long-term storage.

The reason behind this is that certain metals can react with the acidic compounds in coffee, leading to an undesirable metallic taste or even potential health concerns. The acidity can cause a chemical reaction with metals like aluminum, copper, or iron, resulting in the leaching of metallic ions into the liquid.

Over time, as your cold brew sits in contact with these metals, the metallic taste can become increasingly pronounced, overpowering the intended flavors of the coffee. This can lead to an unpleasant drinking experience and may even cause digestive issues in some individuals.

Instead, opt for containers made of glass, food-grade plastic, or stainless steel. Glass is an excellent choice as it is inert and won’t react with the coffee’s acidity. Food-grade plastics, such as those made from polyethylene or polypropylene, are also safe options. Stainless steel containers can be used, but it’s important to ensure they are high-quality and specifically designed for food storage to prevent any potential leaching.

By avoiding metal containers, you can preserve the integrity of your cold brew’s flavor and ensure a safe, enjoyable drinking experience.

Get the Temperature Right

Temperature is a critical factor in determining the shelf life of your cold brew coffee. Proper temperature control not only helps to preserve the delicate flavors but also inhibits the growth of harmful microorganisms, ensuring your brew remains safe for consumption.

Ideally, cold brew coffee should be stored in the refrigerator, at a temperature between 35 degrees (F) and 38 degrees (F). This cool temperature range helps to slow down the oxidation process that contributes to flavor degradation, as well as inhibiting the growth of most bacteria and molds.

Even in the refrigerator, your cold brew coffee will have a limited shelf life. While refrigeration slows down the spoilage processes, it doesn’t halt them entirely. As a general guideline, cold brew stored in the fridge can typically last for up to 14 days before becoming unsafe for consumption, although flavors may start to degrade after 5 to 7 days.

Use High-Quality Coffee Beans to Begin With

While proper storage techniques are essential for maximizing the shelf life of your cold brew coffee, the quality of your brew starts even before the steeping process begins. Using high-quality, fresh coffee beans for cold brew is crucial if you want to enjoy your coffee at its best for as long as possible.

When you start with premium beans that are freshly roasted and bursting with flavor, you’re giving yourself a head start in the flavor department. These high-quality beans are packed with rich, nuanced flavors that can withstand the test of time better than pre-ground grocery store coffee, for example.

On the other hand, if you start with stale, low-quality beans, you’re essentially setting yourself up for a rapid decline in flavor. These beans may already have lost a significant portion of their aroma and taste due to improper storage or extended shelf life, leaving you with a lackluster cold brew from the very beginning.

Even with meticulous storage techniques, a cold brew made from subpar beans may only retain its decent flavor for a day or two before becoming flat and unappetizing. The delicate flavor compounds in these beans are already compromised, making them more susceptible to further degradation during storage.

Additionally, high-quality beans often have a higher concentration of natural antioxidants and other compounds that can help slow down the oxidation process, further extending the shelf life of your cold brew.

Purge With CO2 or Nitrogen

If you’re serious about maximizing the shelf life of your cold brew coffee, consider employing a technique used in the wine industry: purging with carbon dioxide (CO2) or nitrogen gas. This method involves displacing the oxygen in the headspace of your storage container with an inert gas, effectively preventing oxidation and inhibiting the growth of microorganisms.

You can purchase a wine preserver system specifically designed for this purpose. These devices typically come with a small canister of CO2 or nitrogen gas and a nozzle that attaches to the opening of your container. After filling the container with your cold brew, you simply insert the nozzle and release the gas, which will displace the oxygen inside.

The reason this technique works so effectively is that CO2 and nitrogen are inert gasses, meaning they do not participate in chemical reactions or support the growth of microorganisms. By replacing the oxygen in the headspace with one of these gasses, you’re essentially creating an anaerobic (oxygen-free) environment that prevents oxidation and inhibits the proliferation of bacteria and molds.

It’s important to note that while purging with CO2 or nitrogen can significantly extend the shelf life of your cold brew, it’s not a substitute for proper refrigeration. These gasses merely create an oxygen-free environment; they do not halt all chemical reactions or completely prevent microbial growth. Therefore, it’s still important to store your purged cold brew in the refrigerator to achieve maximum longevity.

Is It Dangerous to Drink Old Cold Brew Coffee?

While the temptation to stretch out the lifespan of your cold brew coffee may be strong, especially when you’ve invested time and effort into brewing it, consuming old cold brew that has sat for more than 10 to 14 days can pose serious health risks that should not be taken lightly.

As we’ve discussed, cold brew coffee is susceptible to bacterial growth after an extended period of storage. Even in the refrigerator, where temperatures are lower and designed to inhibit microbial proliferation, harmful bacteria can still find a way to thrive if given enough time.

Some of the most common bacteria that can grow in old cold brew coffee include Escherichia coli (E. coli), Salmonella, and Listeria monocytogenes. These microorganisms can cause a range of illnesses, from mild food poisoning symptoms like nausea, vomiting, and diarrhea to more severe conditions like meningitis or even life-threatening complications in individuals with compromised immune systems.

Additionally, as cold brew coffee ages, it can become a breeding ground for mold growth, which can produce mycotoxins—toxic substances that can cause various adverse health effects. Mycotoxin exposure has been linked to issues such as liver and kidney damage, neurological disorders, and even an increased risk of certain types of cancer.

It’s important to understand that the risks associated with consuming old cold brew coffee go beyond just an unpleasant taste or aroma. The potential health consequences can be severe and long-lasting, making it imperative to exercise caution and err on the side of safety.

If you notice any signs of spoilage, such as an off-putting smell, visible mold growth, or a sour taste, it’s crucial to discard the cold brew immediately, regardless of how much time and effort went into brewing it. Your health should always take precedence over the desire to extend the lifespan of your beverage.

Frequently Asked Questions

Can I freeze cold brew coffee to extend its shelf life?

While freezing cold brew coffee may seem like a convenient way to extend its shelf life, it’s generally not recommended. The freezing process can cause the formation of ice crystals, which can disrupt the delicate balance of flavor compounds and result in a degraded taste when thawed. Additionally, the expansion and contraction of the liquid during freezing and thawing can compromise the integrity of the container, potentially leading to leaks or contamination. If you must freeze cold brew, it’s best to do so in small portions and consume it within a month for optimal flavor and safety.

Is it safe to drink cold brew coffee that has been left at room temperature for a few hours?

It’s best to avoid consuming cold brew coffee that has been left at room temperature for an extended period, especially if it’s been longer than 2 hours. Room temperature conditions can accelerate the growth of harmful bacteria and molds, rendering the coffee unsafe for consumption. If your cold brew has been sitting out for more than 2 hours, you should discard it to prevent the risk of foodborne illnesses.

Can I reuse the same container for storing multiple batches of cold brew coffee?

It’s possible to reuse the same container for storing multiple batches of cold brew coffee, but it’s important to clean and sanitize the container thoroughly between uses. Any residual organic matter or moisture can provide a breeding ground for bacteria and molds, potentially compromising the safety and quality of your new batch. It’s recommended to wash the container with hot, soapy water, followed by a sanitizing solution (such as a diluted bleach solution or vinegar) to ensure it’s completely clean before refilling with fresh cold brew.