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Does Beer Go Bad If Left In a Hot Car? (Explained!)

As a beer enthusiast and brewer, I’m always looking for ways to ensure my beer stays as fresh and delicious as possible. One question that often comes up among fellow beer lovers is whether or not beer goes bad if left in a hot car.

Does beer go bad if left in a hot car? Yes, beer can go bad if left in a hot car. The heat can cause a variety of adverse effects on the beer, such as altering its taste, accelerating the aging process, and even causing cans and bottles to explode.

It’s essential to store beer in a cool and dark environment to preserve its quality and flavor.

In this blog post, I will explore this topic in depth, drawing from my personal experiences, scientific research, and general knowledge about beer and its components. So, let’s dive in and find out if your beer is safe in a hot car!

The Science Behind Beer Spoilage

Beer spoilage in high temperatures and exposure to UV light is primarily caused by chemical reactions and microbial growth.

Let’s explore the science behind these processes!

1. Heat Accelerates Oxidation

Beer is sensitive to oxidation, which occurs when oxygen reacts with the compounds in beer, leading to off-flavors and aromas.

One of the primary effects of heat on beer is that it accelerates the oxidation process. When beer is exposed to high temperatures, the oxygen trapped inside the bottle or can reacts more quickly with the beer, causing it to become stale and lose its freshness.

This can result in a cardboard-like taste or a sour, vinegary smell.

So, when beer is exposed to high temperatures, several undesirable changes occur due to:

a. Oxidation: Elevated temperatures accelerate the oxidation process in beer. Oxygen reacts with various components of beer, such as hops and lipids, leading to the development of off-flavors and a stale taste.

b. Other Chemical Reactions: Heat can promote chemical reactions within beer, causing the breakdown of complex compounds. This can result in the formation of off-flavors, including “skunky” or “cooked” aromas. Lightstruck or skunked beer is a result of the interaction between hop-derived compounds and light, particularly ultraviolet (UV) light, as we will discuss in the next section.

c. Yeast Activity: If the beer is home brewer or not pasteurized, campden treated or filtered, high temperatures can also impact the activity of yeast in beer. If the beer gets too warm, yeast may become more active, leading to over-fermentation, off-flavors, and even the production of off-gases that can cause the beer to overflow or spoil.

2. The Impact of Light on Beer

Another factor to consider is the impact of light on beer. When beer is exposed to sunlight or even artificial light for extended periods, it can cause the hops in the beer to break down and produce unpleasant flavors, commonly referred to as “skunked” beer.

Skunking: Hop compounds, particularly alpha acids, can undergo a photochemical reaction when exposed to UV light.

This reaction produces a compound called 3-methyl-2-butene-1-thiol (MBT), which has a distinct skunky odor. This is the same compound that is responsible for the smell of skunks.

Even a brief exposure to UV light can trigger this reaction, leading to a noticeable off-flavor in the beer.

Riboflavin Degradation: Riboflavin, a light-sensitive compound present in beer, can also undergo degradation upon exposure to UV light. This degradation can result in the development of “lightstruck” flavors, which are often described as being reminiscent of wet cardboard or a stale taste.

This reaction can happen within minutes of exposure to strong light. While leaving beer in a hot car may not directly expose it to light, the increased temperature can accelerate the light-struck reaction if the beer is exposed to any light at all.

3. The Role of Temperature Fluctuations

When beer experiences significant temperature fluctuations, it can cause the beer to expand and contract, leading to the release of carbon dioxide.

This release of CO2 can result in a flat, lifeless beer with a diminished head and a lack of carbonation. When beer is left in a hot car, it’s highly likely to experience temperature fluctuations, especially if the car cools down at night and then heats up again during the day.

4. Cans vs. Bottles: Which Is More Susceptible to Heat Damage?

When discussing the potential of beer going bad in a hot car, it’s essential to consider the packaging. While both cans and bottles can be affected by heat, cans are generally more resilient than bottles.

Cans are more adept at blocking out light and protecting the beer from light-struck reactions. However, both cans and bottles can explode if the pressure inside them becomes too high due to heat and carbonation.

5. The Impact on High-ABV and Barrel-Aged Beers

Some beer styles may be more susceptible to heat damage than others. High-ABV (alcohol by volume) beers and barrel-aged beers, for example, can be more sensitive to temperature fluctuations.

These beers often have more complex flavors and aromas, which can be easily thrown off balance by exposure to heat. Additionally, the higher alcohol content in these beers can cause them to become more volatile in hot temperatures, potentially leading to bottle explosions.

6. My Personal Experience: Beer Gone Bad in a Hot Car

As a beer enthusiast, I’ve experienced the disappointment of discovering that a beer left in a hot car has gone bad. On a sunny summer day, I inadvertently left a six-pack of IPA in the trunk of my car for several hours.

When I finally remembered and retrieved the beer, I noticed that the cans were slightly swollen, and the beer itself had a strange, almost skunky aroma.

Upon tasting, the beer was flat, and the hoppy flavors that I loved had been replaced by a stale, cardboard-like taste. It was a disheartening experience, and one that I have been careful not to repeat.

7. The Ideal Storage Conditions for Beer

To ensure your beer stays fresh and delicious, it’s essential to store it in the right conditions. The ideal storage environment for beer is a cool, dark place with a consistent temperature.

A basement or a dedicated beer fridge are both excellent options for maintaining proper storage conditions.

Avoid exposing your beer to direct sunlight, and try to keep the temperature as stable as possible to prevent any adverse reactions.

8. What To Do If You Must Leave Beer in a Hot Car

If you find yourself in a situation where you have no choice but to leave beer in a hot car, there are a few steps you can take to mitigate the potential damage. First, try to park your car in a shady spot, or use a sunshade to block direct sunlight.

Additionally, consider wrapping your beer in a blanket, towel, or even a coat to provide a layer of insulation to help regulate the temperature.

Finally, try to minimize the amount of time the beer spends in the hot car, and transfer it to proper storage conditions as soon as possible.

However, the danger of leaving your beer in the car during summer, depends, of course, on how hot the car is likely to get!

How Hot Does a Car Get in Summer?

During the scorching summer months, a parked car can transform into a sweltering oven, subject to intense heat buildup that can reach staggering temperatures.

The extent to which a car heats up depends on various factors, including its color, location (latitude), and local weather conditions.

It is indeed a widely accepted notion that, in hot countries and under the blazing sun, a car can easily reach temperatures exceeding 140°F (60°C) when left parked in direct sunlight.

  1. Car Color: The color of a car plays a crucial role in determining how hot it gets in the sun. Dark-colored cars, such as black or dark blue, absorb more sunlight and, subsequently, heat up faster and to higher temperatures compared to lighter-colored cars, like white or silver. This is due to the fact that darker colors absorb more of the sun’s radiant energy while lighter colors reflect it.
  2. Latitude and Local Climate: The geographical location of the car, primarily its proximity to the equator, can significantly impact how hot it gets. Cars parked in regions closer to the equator experience more intense and prolonged exposure to direct sunlight throughout the year, resulting in higher interior temperatures. Additionally, areas with high temperatures and low humidity levels tend to exacerbate the heat inside a parked car.
  3. Seasonal Variations: While summer is generally associated with scorching temperatures, the time of day and season can influence how hot a car becomes. In the peak of summer, midday sun can be exceptionally intense and raise the interior temperature rapidly. However, even in spring and fall, cars can still become dangerously hot if left exposed to direct sunlight for extended periods.
  4. Insulation and Ventilation: The design and build of the car, including its insulation and ventilation systems, can impact how effectively it retains or dissipates heat. Modern cars are designed with insulation materials to help maintain a comfortable interior temperature, but these measures can only go so far when subjected to extreme heat.
  5. Window Tint and Shade: Using window tinting and parking in the shade can significantly mitigate the heat buildup in a parked car. Tinted windows reduce the amount of solar radiation that enters the vehicle, while parking in the shade can provide a substantial reduction in interior temperature compared to being exposed to direct sunlight.
  6. Duration of Exposure: The longer a car is exposed to direct sunlight, the hotter it will become. Even on moderately hot days, a car left in the sun for several hours can reach dangerously high temperatures. This poses significant risks to occupants and can cause damage to the vehicle’s interior, including dashboard and upholstery.

The extreme temperatures that a car can reach in the summer sun emphasize the importance of taking precautions, such as using sunshades, window tints, and, most importantly, never leaving children, pets, or vulnerable individuals inside a parked car, even for short periods.

9. Can Beer Explode if Left in a Hot Car?

Yes, beer can potentially explode if left in a hot car under certain conditions, but it is highly unlikely to happen. When beer is exposed to high temperatures, the liquid inside the can or bottle can expand and create pressure.

If the pressure becomes too high and exceeds the structural integrity of the container, it can lead to the beer can or bottle rupturing or exploding.

Here’s why this can happen:

  1. Temperature: Heat causes the liquid in the beer to expand, which increases the pressure inside the container. The hotter the environment, the faster this expansion and pressure buildup occur.
  2. Closed Container: Beer bottles and cans are typically sealed with little room for air to escape. As the liquid inside expands due to the heat, the pressure inside the container increases.
  3. Weak Points: If there are any defects or weak points in the container, such as microcracks or imperfections, the increased pressure could cause the container to fail.
  4. Bottle Conditioned Beers: Some craft beers undergo a secondary fermentation process in the bottle, resulting in natural carbonation. These beers have live yeast, which can produce additional carbon dioxide, increasing pressure if subjected to high temperatures.

If the pressure builds up enough and the container fails, it can lead to the beer forcefully ejecting from the container or the container itself bursting. This could result in a messy and potentially dangerous situation.

To avoid this issue, it’s best to store beer in a cool and dry place, away from direct sunlight or extreme heat. If you find yourself with beer that has been exposed to high temperatures for an extended period, it’s safer to let it cool down before opening it, or simply discard it to avoid any potential risks.

10. How Long can you Safely Leave Beer in a Hot Car?

Leaving beer in a hot car can lead to various issues, and it’s generally not recommended, especially during hot weather conditions.

In my experience, you should not leave beer for more than 1-2 hours on a really hot summer day.

After that it will start to impact taste and carbonation. Leave it for much longer and it can lead to more worrisome effects.

The exact duration that beer can remain safely in a hot car depends on several factors, such as the temperature outside, the duration of exposure to heat, and the alcohol content of the beer.

Here are some general guidelines to consider:

  1. Quality degradation: High temperatures can accelerate the aging process of beer, causing it to go stale and develop off-flavors. This is especially true for beers with lower alcohol content, such as light beers or some craft beers.
  2. Risk of spoilage: If the beer is exposed to extreme heat for an extended period, it can spoil and become undrinkable due to the growth of harmful bacteria or yeast.
  3. Can explosions: In extreme cases, beer cans or bottles may explode when exposed to high temperatures. The pressure inside the container can build up due to the expansion of gases, causing the container to burst.
  4. Alcohol content matters: Beers with higher alcohol content (e.g., craft beers or some ales) generally have a better chance of resisting spoilage and maintaining their quality in hot conditions compared to lower alcohol content beers.

As a general rule of thumb, if you plan to consume the beer later, it’s best to avoid leaving it in a hot car for an extended period, especially during scorching weather. If you must transport beer in a hot car, try to keep it in a cooler or insulated bag with ice packs to minimize exposure to heat.

If beer has been sitting in a hot car for an extended period, it’s safer to err on the side of caution and consider it compromised, even if it might not show any visible signs of damage.

Drinking compromised beer could lead to an unpleasant taste or, in some cases, potential health risks if harmful microorganisms have grown in the beer.


In conclusion, yes, beer can go bad if left in a hot car. The heat can cause a variety of issues, including accelerated oxidation, light-struck reactions, temperature fluctuations, and even explosions.

To preserve the quality and flavor of your beer, it’s crucial to store it in a cool, dark environment with a stable temperature. If you must leave beer in a hot car, take precautions to minimize the potential damage and transfer it to proper storage conditions as soon as you can.

10 Final Facts About Beer and Heat Exposure:

1. Heat accelerates the oxidation process in beer, leading to off-flavors and aromas.
2. Light exposure can cause beer to become “skunked” due to the breakdown of hops.
3. Temperature fluctuations can cause beer to lose carbonation and become flat.
4. Cans are generally more resilient to heat damage than bottles, but both can explode under extreme conditions.
5. High-ABV and barrel-aged beers are more susceptible to heat damage due to their complex flavors and higher volatility.
6. Beer should ideally be stored in a cool, dark environment with a consistent temperature.
7. Parking in the shade and using a sunshade can help protect beer left in a hot car.
8. Insulating your beer with a blanket, towel, or coat can help regulate the temperature in a hot car.
9. Minimizing the time beer spends in a hot car is crucial for preserving its quality.
10. Always transfer beer to proper storage conditions as soon as possible to maintain its freshness and flavor.


Does alcohol go bad if left in a hot car?

Yes, alcoholic beverages like beer can go bad if left in a hot car. High temperatures can cause changes in the chemical composition of the drink, leading to a loss of flavor, aroma, and quality. Additionally, extreme heat can cause the alcoholic drinks to expand and potentially even break the container it is stored in. It is best to store alcohol in a cool, dark place to maintain its quality.

Does alcohol get bad if it gets hot?

Yes, alcohol can get bad if it gets too hot. High temperatures can cause chemical reactions that alter the flavor and aroma of the alcohol, making it taste off or unpleasant. Additionally, excessive heat can cause the alcohol to evaporate, leading to a loss of volume and potency. It is best to store alcohol in a cool, dark place to maintain its quality.

Is it safe to drink beer left in hot car?

Yes, it is usually safe to drink beer left in a hot car for shorter periods of time. The heat will change the taste, but usually not make it unsafe to drink (just disgusting…).

Can you leave liquor outside in the heat?

It is not recommended to leave liquor outside in the heat as it can cause the alcohol to evaporate and change the flavor of the liquor. It is best to store liquor in a cool, dark place.

Is wine OK to drink after being left in hot car?

No, it is not recommended to drink wine that has been left in a hot car as high temperatures can cause the wine to spoil, oxidize, or even develop harmful bacteria.

Can liquor sit out in the heat?

Liquor can sit out in the heat without spoiling or going bad, but it may affect the taste and quality of the liquor over time. It is best to store liquor in a cool, dark place to maintain its quality.

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