Cold brew coffee has become increasingly popular in recent years. The smooth, less acidic taste makes it an appealing choice for coffee drinkers. But like any perishable food or beverage, proper storage is important for maintaining quality and safety.
Can you leave cold brew out overnight?
The short answer is no, it’s generally not recommended to leave cold brew out at room temperature overnight. Cold brew is usually brewed with room temperature or cold water and then steeped in the fridge 12-24 hours. The cold temperature helps extract the flavors more slowly while also inhibiting microbial growth.
Once brewed, cold brew should continue to be stored chilled in the refrigerator. If left out overnight at room temperature, the risks include:
- Bacterial growth – Cold brew is not a hot brewed coffee that starts out sterile. The cold water does not kill bacteria as effectively. Leaving it out allows bacteria to multiply.
- off flavors – The taste can change more rapidly, taking on sour, unpleasant flavors.
- Food safety – harbor potentially harmful bacteria when left at room temperature too long.
How long can cold brew sit out?
The maximum time cold brew should be left out at room temperature is 4 hours. Similar to milk or other perishable beverages, bacterial growth can occur if left out too long.
Here are some general guidelines for cold brew storage:
| Storage Time | Temperature |
|---|---|
| 0-4 hours | Room temperature |
| 1-2 weeks | Refrigerator 40°F or below |
| 2-3 months | Freezer 0°F or below |
For optimal flavor and safety, cold brew should be stored in the refrigerator and consumed within 1-2 weeks. It can last up to 3 months in the freezer but may take on more bitter notes over time.
What happens if you drink cold brew left out overnight?
Drinking cold brew that has sat at room temperature overnight is risky from a food safety standpoint. Bacteria multiples rapidly between temperatures of 40°F and 140°F.
Potential risks include:
- Food poisoning – bacteria like Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus can cause vomiting and diarrhea.
- Toxin production – some bacteria release heat-stable toxins that are not destroyed by further heating or boiling.
- Spoiled taste – from faster growing bacteria and yeasts.
The chance of getting sick depends on exactly how long the cold brew was left out, temperatures, acidity, and your individual immunity. But it is best to play it safe and avoid drinking cold brew that has sat out overnight.
Does heating up old cold brew make it safe?
Heating or rebrewing cold brew that has been left out too long does not necessarily make it safe to drink again. Some bacteria produce toxins that are not neutralized by further heating. For example, staphylococcus aureus can release an enterotoxin that causes vomiting.
Boiling may kill most bacteria that grew overnight, but it does not remove or deactivate the toxins already produced. Heating cannot reverse the spoiled taste either. Always err on the side of caution and discard cold brew that has sat out too long.
Tips for handling cold brew properly
Here are some tips for properly storing and handling cold brew coffee to keep it safe and tasting fresh:
- Store in the refrigerator immediately after brewing. Keep temperatures at 40°F or below.
- Avoid returning already poured or handled cold brew back to the storage container. This can introduce bacteria.
- Use clean utensils and containers when preparing or storing.
- Consume within 1 week for best quality.
- Don’t leave it sitting out more than 4 hours.
- Store in air-tight containers to minimize oxidation.
- Freeze for longer storage up to 3 months.
Handling cold brew properly from start to finish will help prevent foodborne illness and maintain the smooth flavor cold brew is known for.
Is it safe to add ice to leftover cold brew?
Adding fresh ice to leftover cold brew that has been continuously refrigerated can be safe. The key factors are the age of the cold brew and the temperature it has been held at.
As long as the cold brew has been stored 40°F or colder and consumed within 1 week of brewing, adding ice should not pose a high risk. The ice will chill and slightly dilute the concentration. But it does not drastically change the safety or quality.
However, ice should not be relied on to “re-chill” cold brew that has sat at room temperature for several hours. At that point, bacterial growth may have already reached unsafe levels.
Safety tips for icing leftover cold brew
- Only use fresh, clean ice.
- Avoid “topping off” containers or returning previously poured cold brew back to the storage container.
- Use a clean spoon or scoop when handling ice to prevent contamination.
- Keep reconstituted cold brew chilled until serving.
- Discard any cold brew with off odors, tastes, or appearance.
With proper handling, icing stored cold brew can be safe. But take care not to introduce new bacteria or use ice to attempt “re-chilling” warm cold brew.
Does alcohol content make cold brew safer?
Some cold brew coffee recipes or products contain alcohol, usually vodka or whiskey. The addition of distilled spirits can help extend the shelf life by inhibiting bacterial growth due to the alcohol content.
Alcohol levels between 15-30% are typically most effective for food preservation. Commercial cold brew producers may use alcohol concentrations in this range.
However, homemade cold brew recipes generally have lower amounts of spirits added. A splash of vodka, whiskey, or liqueur may provide flavor, but is often not enough to significantly preserve homemade cold brew. Bacteria can still multiply in cold brew with alcohol if left out too long.
Tips for making alcoholic cold brew
- Use liquor with a higher proof. Vodka or whiskey work better than wine or beer.
- Aim for an alcohol content between 15-30% for max preservation effects.
- Store in the refrigerator and consume within 1-2 weeks.
- Check for any off odors, colors, or curdling that may indicate spoilage.
- Avoid letting young children or those with alcohol sensitivities consume without first being made aware of the alcohol content.
While the addition of alcohol can help extend the shelf life of cold brew, it does not make it 100% safe from spoiling, especially when left out overnight. Refrigerated storage and consuming within a week or two is still recommended.
Should you add milk or cream to old cold brew?
It’s not recommended to add milk, cream, or other dairy products to cold brew that has been sitting out past refrigeration times. The dairy may not make the coffee itself safe, but could pose its own risks.
Added dairy also provides an additional source of bacteria and speeds up spoilage. Bacteria multiply much faster in milk and cream than just cold brew alone.
Possible risks include:
- Soured, curdled milk from lactobacillus bacteria
- Unpleasant flavors from rapid oxidation
- Food poisoning from E. coli, salmonella, or other pathogens transferring to the dairy
For best safety and quality, only add fresh refrigerated milk, cream, or other dairy to freshly prepared or properly stored cold brew. Avoid mixing dairy products with cold brew that has been left out too long.
Can you reheat leftover cold brew concentrate?
Cold brew coffee concentrate that has been continuously refrigerated and is less than 1 week old can often be safely reheated or rebrewed. Bringing it back up to hot temperatures can help extend the shelf life slightly longer.
To reheat cold brew concentrate:
- Remove any visible mold or sediment
- Bring water, milk, or other liquids to a boil
- Mix in the chilled concentrate
- Heat through at least 165°F for food safety
However, cold brew that has been left out at room temperature for over 4 hours should still be discarded and not reheated or consumed. At that point, bacteria may have multiplied to unsafe levels or produced toxins that are not destroyed by reheating.
Storage tips for leftover cold brew concentrate
- Refrigerate concentrate immediately in clean, airtight containers
- Use concentrate within 1 week for best flavor
- Discard if mold appears or you notice off odors or appearance
- Avoid adding back poured concentrate into the storage container
With proper refrigeration, leftover cold brew concentrate can often be reheated safely. But it will not improve coffee that has already been left out too long and started deteriorating in quality or safety.
Can you make iced coffee from cold brew that sat out?
It’s generally not recommended to make iced coffee using cold brew that has sat at room temperature overnight or longer. Since the cold brew itself would be considered unsafe after sitting out too long, adding ice or chilling it again does not undo the risk of bacterial growth.
There are a few concerns with trying to remake iced coffee from warm cold brew:
- Bacteria or toxins can remain even when chilled again
- Unpleasant odors and taste from oxidation
- Dilution does not equal sterilization
- Contaminated equipment can further spread bacteria
To enjoy cold brew over ice safely, it’s ideal to:
- Brew fresh cold brew
- Immediately refrigerate after brewing
- Serve directly over ice, avoiding watering down or contamination
- Discard any unused portion after 1 week
Trying to reconstitute cold brew that has already sat out and deteriorated is not recommended. The safest choice is to discard it and brew a fresh batch.
Can you mix old cold brew into a smoothie or shake?
Blending spoiled cold brew into a smoothie or milkshake is not recommended from a food safety standpoint. Any bacterial contamination in the cold brew remains and can still pose a foodborne illness risk.
Potential risks of consuming contaminated cold brew in blended drinks include:
- Vomiting or diarrhea from pathogenic bacteria
- Toxins are not destroyed by blending or whipping
- Off odors and flavors carry through into the finished drink
Best practice is to avoid using cold brew that has been left out at room temperature overnight or longer in any type of food or beverage. Discard it and use fresh cold brew only.
Tips for safely adding cold brew to drinks
When adding cold brew to smoothies, shakes, or other blended beverages, keep these guidelines in mind:
- Only use cold brew stored properly in the refrigerator
- Limit to cold brew made within the past week
- Do not mix in any old concentrations or batches
- Blend and serve drinks immediately
- Discard any leftovers, do not return to the fridge
Fresh, properly handled cold brew can be an excellent addition to blended drinks. But contaminated cold brew poses too much risk of foodborne illness to consume in any form, including smoothies or shakes.
Conclusion
Leaving cold brew coffee out at room temperature overnight can create an environment where bacteria multiply quickly. Consuming it poses a significant food safety risk.
To enjoy fresh, safe cold brew coffee:
- Store in the refrigerator after brewing
- Avoid leaving it out more than 4 hours
- Consume within 1 week
- Do not drink or reuse cold brew left out overnight
- Improper handling cannot be reversed
With proper storage and handling, you can safely enjoy delicious cold brew coffee. But take care not to leave it sitting out at room temperature for extended periods of time, as harmful bacteria can grow rapidly under those conditions.
