Oat milk, like other plant-based milks, does not contain the same proteins found in dairy milk that can spoil at room temperature. However, oat milk should still be handled with care once opened and should not be left unrefrigerated for extended periods of time.
How long can oat milk sit out unrefrigerated?
An unopened carton or bottle of oat milk can be stored at room temperature prior to opening. Once opened, it is generally recommended to refrigerate oat milk and use within 7-10 days. If unrefrigerated, opened oat milk should not be left out for more than 2 hours at room temperature or 1 hour at temperatures above 90°F.
Does oat milk need to be refrigerated after opening?
Yes, it is important to refrigerate oat milk after opening. Leaving oat milk unrefrigerated for too long allows bacteria and mold to grow, even though it does not contain dairy. The naturally occurring fats and sugars in oat milk can be broken down by microbes at warm temperatures.
What happens if you drink oat milk that has been left out?
Drinking oat milk that has been left unrefrigerated for too long can lead to food poisoning or upset stomach. Signs that oat milk has spoiled after sitting out include:
- Sour, curdled texture
- Off smells
- Mold visible on surface
- Fizzing or bubbling when container opened
Consuming spoiled oat milk can cause nausea, vomiting, diarrhea, and abdominal cramping. The severity depends on the amount consumed and the person’s sensitivity.
How to tell if unrefrigerated oat milk is still good
Check for the following signs that opened oat milk is still safe to drink after sitting out:
- Smooth, uniform consistency
- Original color – no darkening
- Pleasant, mild oat smell
- No separation of liquid and solids
- No noticeable sour taste
- Carton still feels firm – not puffy
- No visible mold, sliminess, or bubbles
Use your senses of sight, smell and taste to determine if the quality has declined. Discard any oat milk that shows signs of spoilage.
Tips for storing opened oat milk
To maximize the shelf life of opened oat milk:
- Refrigerate after opening – store in fridge at 40°F or below
- Keep container tightly sealed when not in use
- Use clean utensils to remove oat milk from carton
- Do not return unused milk back into the container after pouring
- Consume within 7 days and check for signs of spoilage before use
- Mark container with date opened for easy tracking
Can you freeze oat milk to extend shelf life?
Yes, freezing is an option for storing oat milk longer term. To freeze:
- Pour milk into airtight containers or freezer bags
- Remove as much air as possible before sealing
- Label with date and freeze for up to 3 months
- Thaw in fridge before using and shake well to recombine
Freezing can cause some separation of liquid and solids. Oat milk may take on a slightly different texture after thawing but is still safe to consume.
Is it safe to cook or bake with oat milk that was left out?
It is not recommended to use oat milk that has been sitting unrefrigerated for recipes that will not be thoroughly cooked. The heating process during baking or cooking may not destroy all potential spoilage organisms or toxins.
Oat milk that is clearly spoiled should never be used. Oat milk that was left out briefly beyond the recommended 2 hour limit can be used for baking items that will be fully cooked like breads. Use caution when adding it to recipes without further cooking like smoothies.
Should oat milk be refrigerated in the store?
Oat milk sold in refrigerated cases in the store should be kept refrigerated until you are ready to use it at home. Some shelf-stable varieties can be stored in the pantry until opened, but always check the label for the manufacturer’s suggested storage instructions.
Refrigerated oat milk generally has a shorter shelf life than shelf-stable cartons designed for pantry storage. Look for “keep refrigerated” or a “use-by date” on the label to determine if it requires fridge storage.
Can you make homemade oat milk and leave it out?
Homemade oat milk has an even shorter shelf life compared to store-bought versions. Since homemade oat milk does not go through the same high-pressure processing, it should always be stored in the refrigerator and used within 2-4 days. Do not leave homemade oat milk unrefrigerated for more than 1-2 hours.
To extend the shelf life of homemade oat milk:
- Use fresh oats and clean utensils
- Strain well to remove solids
- Store in very clean, airtight bottles
- Refrigerate immediately after making
- Freeze in portions for longer term storage
Discard any homemade oat milk that smells odd or shows signs of spoilage.
Is it possible to make shelf-stable oat milk at home?
It is challenging to make shelf-stable oat milk at home that can be safely stored at room temperature for extended periods before opening. High-pressure processing used by manufacturers is difficult to replicate in a home kitchen.
To make homemade oat milk last a bit longer, you can try:
- Heating milk briefly to 180°F to reduce bacteria levels
- Cooling quickly and storing in sterile bottles
- Adding preservatives like citric acid or vitamin E
However, homemade oat milk with natural ingredients still has a relatively short shelf life compared to store-bought. It is best to refrigerate homemade oat milk and use quickly for food safety.
Does the brand of oat milk affect refrigerator requirements?
All brands of oat milk should be refrigerated after opening, regardless of ingredients. Some factors that may influence shelf life:
| Brand Factor | Impact on Shelf Life |
|---|---|
| Fat content | Full fat versions may spoil faster |
| Processing method | Shelf-stable milk processed for pantry storage may last slightly longer refrigerated |
| Additives | Preservatives can help prolong refrigerated shelf life |
| Packaging | Quality packaging prevents oxygen exposure |
However, all brands and varieties of opened oat milk should be refrigerated and used quickly. Check bottle for storage guidance specific to that product.
Does the container type impact refrigeration needs?
The packaging or bottle material does not make a significant difference in whether opened oat milk needs refrigeration. The key factors are:
- Access to oxygen – Even airtight packaging allows some air exposure which can degrade quality over time
- Contamination – Bacteria and mold can be introduced each time container is opened
- Light exposure – UV light can damage nutrients and flavor
To maximize shelf life, choose opaque, high-quality containers and limit opening. But always refrigerate after opening, regardless of bottle type.
Common oat milk containers and refrigeration needs:
| Container | Refrigeration Required After Opening? |
|---|---|
| Plastic bottle | Yes |
| Paper carton | Yes |
| Glass bottle | Yes |
| Pouch | Yes |
Does oat milk for coffee shops need refrigeration?
Commercial oat milk intended for use in coffee shops should always be refrigerated. Milk alternatives used in large beverage dispensers, as well as small single-serve containers, require refrigeration both before and after opening.
Leaving oat milk unrefrigerated, especially for extended periods, allows bacterial growth. This poses a health risk if used in beverages without further cooking. Room temperature milk should not be served directly over ice or with cold drinks.
Coffee shops should follow food safety protocols and refrigerate oat milk immediately upon delivery. Discard any that has been left out too long and is no longer deemed safe to use in drinks.
Tips for coffee shops using oat milk:
- Refrigerate upon delivery before and after opening
- Use clean utensils and dispensers to prevent contamination
- Pour into beverages directly from refrigerated storage
- Do not leave out at room temperature for more than 2 hours
- Monitor refrigerator temperature to maintain below 40°F
Conclusion
Oat milk, like other plant-based milks, lacks the proteins of dairy milk that can spoil at room temperature. However, leaving opened oat milk unrefrigerated still allows harmful bacterial growth. For food safety, it is important to refrigerate oat milk after opening and not leave it sitting out for more than 1-2 hours.
Check oat milk for signs of spoilage like odor, taste and texture changes before consuming, especially if left out too long. Discard any oat milk that has spoiled. Proper refrigerated storage, along with careful handling and use of clean utensils, can help maximize the shelf life after opening.
