Background and Overview
Coffee is one of the most popular beverages in the world and has been enjoyed for centuries, primarily for its stimulating and energizing effects. While coffee can be consumed hot or cold, it can also be enjoyed as a chilled beverage or even cold brew. But when coffee is left sitting out, is it still safe to drink?
The answer lies in the microbial activity and the stability of the compounds that make up coffee. As with any food or drink product, temperature can have a dramatic effect on the composition and shelf life of the product. When coffee is exposed to room temperature or higher, it can cause anaerobic, or oxygen-free, conditions which can be a breeding ground for bacteria and fungus. This can result in the coffee developing an unpleasant taste or smell over time, and it can be unsafe to consume.
In addition to the bacterial activity, coffee may experience oxidation when exposed to air. Oxidation occurs when electrons are removed from the compounds that make up the coffee, resulting in the compounds becoming less stable and leading to the coffee becoming spoiled.
Time Limits
Generally, it is best to avoid coffee that has been sitting out for over two hours. If you are preparing coffee to share, it is best to keep it in a warmed carafe and to avoid leaving it in an environment where it can cool rapidly, such as outside temperatures. A rapid cooling of the coffee can be more damaging than slow cooling. In addition, spills or leaks should be avoided with heated containers as these can also lead to quicker contamination of the coffee.
Also keep in mind that once coffee is re-heated, the potential for microbial contamination is higher. According to a study conducted by the National Centre for Home Food Preservation, heating coffee to a temperature of >165°F (74°C) for over 15 minutes is the optimal time and temperature needed to kill any harmful bacteria.
Impact on Quality
Sitting out for long periods of time can have a negative effect on the quality of the coffee. Over time, the aromatic compounds of the coffee will break down, resulting in a much duller flavor and body. In addition, sitting out will also reduce the caffeine content. The amount of caffeine lost varies with the length of time the coffee is exposed, but it can be as much as 25-30% after two hours.
Health Risks
The bacteria, fungi, and other microbes that may be present in standing coffee can lead to health risks if ingested. These include vomiting, nausea, stomach pains, and diarrhoea. In rare cases, the ingestion of standing coffee can also cause food poisoning.
For pregnant women and those with certain medical conditions, it is always best to avoid consuming standing coffee. This is particularly important for those with weakened immune systems and those with a higher risk of infection.
Preparing Coffee for Storage
If you intend to store coffee for an extended period of time, the best way to do so is in an airtight, temperature-stable container. These containers should be made of BPA-free plastic or glass, with a secure seal. This will ensure the staleness of the coffee is kept to a minimum.
In terms of shelf life, ground coffee will typically last around one to two weeks if stored in an airtight container. Whole bean coffee, on the other hand, may last around three weeks in similar conditions.
Alternatives to Standing Coffee
If you don’t have time to make a fresh cup of coffee every time, there are other alternatives to standing coffee that may be more palatable. These include pre-made cold brew or iced coffee, iced latte cubes, powdered coffee mixes, and some single-serve coffee pods.
These drinks are not only typically safer than standing coffee, but they last much longer, and often serve the same energizing and stimulating effects as hot or cold brew.
Making Coffee Safely
The key to safe and enjoyable coffee is making sure that it is not sitting out for too long, or left in an environment which may cause it to become contaminated. If you are preparing a pot of coffee, make sure you keep it in an insulated carafe and drink it within two hours. If you are making a single-serve cup, drink it immediately. In the event of a spill, make sure to rinse out the container thoroughly before starting a new batch.
Using Other Beverages Instead
If you prefer to avoid re-heated coffee or you do not have the time to make a fresh cup, you can opt for other beverages as an alternative. There are many options available, from water and tea to cold-pressed juices, smoothies, and kombucha.
These beverages are typically lower in caffeine than coffee, but may still give the same feeling of alertness and energy. For those looking for a healthier alternative to coffee, these can be a great option.
Storing Coffee for Later
If you intend to store coffee for an extended length of time, it is important to use airtight, temperature-stable containers. This will ensure that the coffee remains fresh and free from microbial contamination. Whole beans and ground coffee should last around one to two weeks if they are stored in the correct conditions.
It is also important to avoid spills and leaks when storing coffee in containers, as this can lead to contamination. Furthermore, storing coffee in the refrigerator is generally not recommended, as the environment can quickly reduce its flavor and body.
Keeping Coffee Fresh
When it comes to preparing coffee, it is best to avoid leaving it sitting out for any length of time, as this can lead to contamination and spoilage. If you plan to serve coffee for an extended period of time, make sure to keep it in an insulated carafe or container.
It is also important to rinse out spilled coffee immediately and avoid pouring any old coffee back into the pot. These simple steps can help ensure that your coffee is safe and enjoyable for longer periods of time.
