How long can oat milk last in the fridge?

Oat milk has become increasingly popular in recent years as a plant-based milk alternative. But like any perishable food, oat milk has a limited shelf life. So how long does oat milk actually last in the refrigerator before going bad?

Quick Answer

Unopened oat milk will generally stay fresh in the fridge for 5-10 days past the printed date on the carton. Once opened, oat milk will last for 7-10 days when properly stored in a refrigerator set below 40°F. Keep oat milk away from the door, where temperatures fluctuate more.

How to Tell if Oat Milk Has Gone Bad

Here are some signs that your oat milk has spoiled and should be discarded:

  • Sour smell
  • Thick consistency or clumping
  • Mold growth
  • Off flavors like sourness or bitterness
  • Change in color

As oat milk nears its expiration date, separation may begin to occur with the oat particles sinking to the bottom. This alone doesn’t mean it has gone bad, but the taste and aroma will progressively deteriorate. Trust your senses – if it smells or tastes unpleasant in any way, play it safe and toss it.

Factors that Affect How Long Oat Milk Lasts

Several factors impact how long oat milk will stay fresh and appetizing:

Sell-by date

This is not an expiration date, but rather the last date that stores are supposed to display the product. Oat milk can be safely consumed for 5-10 days past the sell-by date as long as it was properly refrigerated.

Opening and exposure to air

Once opened, oxygen can interact with the proteins, fats, and nutrients in oat milk, causing it to degrade more rapidly. Minimize exposure by pouring only what you plan to use right away.

Storage temperature

Cold temperatures slow the growth of bacteria and extend shelf life. Store oat milk at 40°F or below. The fridge door is warmer, so keep it towards the back.

Type of oat milk

Shelf life can vary slightly between brands, or even between flavored and plain versions. Always defer to dates on your specific carton.


Dirty containers or pouring utensils can introduce bacteria. Always wash hands and containers before handling.

How to Store Oat Milk Correctly

Follow these tips to maximize the shelf life of your oat milk:

  • Keep oat milk refrigerated at 40°F or below at all times.
  • Store toward the back of the fridge, away from the door.
  • Wipe off any drips from the carton before putting it away.
  • Keep the cap tightly sealed between use.
  • Pour only the amount needed and immediately return the carton to the fridge.
  • Use clean utensils and glasses to avoid contamination.
  • Don’t return unused oat milk to the carton – it can introduce bacteria.
  • Consume within 7-10 days of opening and don’t go past the sell-by date.
  • Check regularly for signs of spoilage.

Does Oat Milk Go Bad While Sealed?

Properly stored in the refrigerator, unopened oat milk can stay fresh for 5-10 days after the sell-by date. Eventually unwanted fermentation can occur, causing off flavors, clumping, and gas buildup inside the sealed container. Drops in nutritional quality can also begin to take place over time.

To maximize quality and shelf life, store sealed containers towards the back of the fridge at temperatures below 40°F. Occasional separation and settling is normal in unopened products.

How Long Does Oat Milk Last Once Opened?

After opening, oat milk will last 7-10 days when stored properly in the fridge. The introduction of oxygen starts a countdown until spoilage occurs. Be diligent about checking for signs like sour smell, changes in consistency, mold growth, or separation with clear whey on top.

To help oat milk stay fresh longer once opened:

  • Reseal the container tightly after each use.
  • Pour out only what you need and return the carton to the fridge right away.
  • Use clean utensils to avoid introducing bacteria.
  • Don’t return unused milk back into the container.

Does Oat Milk Go Bad Faster After Opening?

Yes, opened oat milk has a shorter shelf life compared to unopened milk. Exposure to oxygen through opening the container accelerates the rate of spoilage. Enzymes, microbes, and chemical reactions begin degrading the proteins, fats, and nutrients in the milk.

Separation, thinning, and off-flavors become noticeable sooner. Keep consumption time limited to 7-10 days once exposed to air and discard if any gross changes occur.

How to Make Oat Milk Last Longer In the Fridge

You can extend the shelf life of oat milk using these simple tricks:

  • Freeze it – Frozen oat milk lasts 2-3 months and thaws well.
  • Add preservatives – A pinch of salt or sugar helps inhibit microbial growth.
  • Acidify it – Stir in a bit of lemon juice to lower the pH.
  • Keep air out – Limit exposure and reseal tightly after use.
  • Clean thoroughly – Sanitize containers, hands, and utensils before handling.
  • Monitor temperature – Keep consistently refrigerated below 40°F.
  • Use quickly – Consume within 7-10 days and don’t go past sell-by date.

Freezing is the best way to significantly extend the shelf life of oat milk. It can be frozen in the original carton or frozen in portions like ice cube trays for later use. Thaw in the refrigerator before using.

Can You Freeze Oat Milk?

Yes, freezing is an excellent way to preserve oat milk far past its typical fridge lifespan. It can be frozen:

  • In its original container for storing bulk milk.
  • In ice cube trays or small containers for individual portions.

Make sure to leave some headspace in containers as liquids expand during freezing. Thawed milk may have some separation, but a quick shake or stir will reincorporate it well for drinking and cooking. Frozen oat milk retains its quality and taste for 2-3 months in a freezer kept at 0°F.

How to Freeze Oat Milk

Follow these simple steps to successfully freeze oat milk:

  1. Check sell-by date and consume milk within 5-10 days of this date before freezing.
  2. Make sure milk is sealed and gently shake carton to remix any separation.
  3. If freezing in original container, leave 1-2 inches of headspace for expansion.
  4. If portioning, fill ice cube trays or small containers leaving space at the top.
  5. Place in coldest part of freezer, preferably at 0°F or below.
  6. Store frozen for up to 2-3 months.

Freezer burn and diminished quality will result if stored longer than the recommended times. For best quality, use frozen oat milk as soon as possible once thawed.

Thawing Frozen Oat Milk

To thaw frozen oat milk properly:

  • Refrigerator thawing is preferred over countertop.
  • Plan ahead – fridge thawing takes 6-8 hours for a full carton.
  • Place in refrigerator and leave overnight before using.
  • Give carton a vigorous shake once thawed and before opening.
  • Consume thawed milk within 7-10 days.

Microwave thawing is not recommended as it can cause separation and inconsistencies in the texture. For quick thawing of ice cube portions, hold under cool running water or submerge sealed cubes in a bowl of cold water instead.

How Long Does Thawed Oat Milk Last in the Fridge?

Properly thawed oat milk can be kept refrigerated for 7-10 days before spoiling. Keep the temperature at 40°F or below. The same signs of spoilage apply to thawed milk as regular oat milk. Discard if you detect any sour smells, change in texture, or mold growth after thawing.

Do not refreeze thawed oat milk. The ice crystals damage the proteins and oat particles, resulting in diminished quality and stability issues. For long term storage, freeze a fresh supply instead.

Does Oat Milk Go Bad in Coffee and Tea?

Oat milk remains safe to drink for the normal fridge life of 7-10 days after opening even if added to hot coffee or tea. However, higher temperatures do accelerate the breakdown of proteins, fats, and nutrients over time.

For best taste, use freshly opened milk and don’t continue drinking beyond 7-10 days even if mixed into hot beverages. Also, be sure to promptly refrigerate any leftover milk rather than leaving out on the counter between uses.

The Shelf Life of Different Types of Oat Milk

Shelf life can vary slightly between the different types of oat milk:

Type Unopened Fridge Life Opened Fridge Life
Plain oat milk 10-14 days past sell-by date 7-10 days
Flavored oat milk 7-10 days past sell-by date 5-7 days
Barista style oat milk 10-14 days past sell-by date 7-10 days

The natural stabilizers and emulsifiers added to barista style oat milk help it maintain freshness a bit longer typically. Flavored varieties tend to have shorter lifespan, so consume those more quickly after opening.

How to Tell When Oat Milk Has Gone Bad

Rely on your senses to determine when oat milk has spoiled and needs to be discarded:

  • Smell – Milk that has soured will have a rancid, sour odor.
  • Appearance – Mold, excessive separation, curdling, and liquid whey are red flags.
  • Texture – Thick consistency or clumping indicates spoilage.
  • Taste – Sour, bitter, or off flavors mean oat milk has gone bad.

When refrigerated properly, the signs of spoilage are quite obvious. Even a small sip of rancid milk should convince you to toss the remainder. Don’t consume oat milk if your senses detect anything unpleasant or different.


Under ideal refrigeration, unopened oat milk remains fresh 5-10 days past the printed sell-by date, and lasts up to 7-10 days once opened. Look for changes in appearance, texture, smell, and taste to determine when oat milk is no longer safe to drink. Freezing can significantly prolong the shelf life, with frozen oat milk staying good for 2-3 months when stored at 0°F. Follow the storage guidelines and trust your senses, and you can enjoy the taste and nutrition of oat milk without having to worry about it going bad prematurely.

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