Oat milk is the most popular plant-based milk, following almond milk. It's easy to love oat milk due to its mild and sweet taste. However, like all milk, oat milk also goes bad after 3-5 days of opening and up to 10 days when refrigerated.
While the storage temperature and period determine oat milk's shelf life, bacteria and fungi contamination shorten it as it converts lactose to lactic acid. The lactic acid causes the milk to curd in about 24 hours, which should tell you to discard your oat milk immediately. However, even without the milk curdling, you should discard the oat milk once you see discoloration and notice changes in its odor.
This article will discuss everything you need to know about oat milk spoilage: how to tell if it has gone bad; what causes it to spoil quickly; and tips on prolonging oat milk shelf life.
Table of Contents
What is Oat Milk?
Oat milk is a plant-based milk made by soaking steel-cut or rolled oats with water, blending them, and pasteurizing them to eliminate harmful bacteria. This process produces sweet, mild-tasting milk that substitutes dairy milk excellently. Commercial oat milk often comes in carton packaging with storage instructions; some oat milk products are shelf-stable and require refrigeration only once opened, while others are refrigerated at all times.
Since oat milk does not add any strong scent or taste, it works well for regular coffee, lattes and cappuccinos, smoothies and protein shakes, and other cold drinks. It also works excellently as a cow's milk substitute in baked goods, pancakes, and even soups.
Does Oat Milk Go Bad?
Unfortunately, like all milk, oat milk goes bad. Due to material deterioration, microbial contamination, and improper storage, both opened and unopened oat milk go bad after some time.
How Long Does Oat Milk Last?
Shelf-Stable Oat Milk
Milk products considered shelf-stable undergo Ultra High-Temperature Pasteurization that kills microbes that cause spoilage. This process heats milk at very high temperatures for a few seconds before packing it for distribution. As a result, you can expect shelf-stable milk to have a longer shelf life.
You can store unopened shelf-stable oat milk on your shelf for up to 12 months or as indicated by the manufacturer. However, even shelf-stable oat milk needs refrigeration to preserve its freshness once opened. You can keep your opened oat milk in the refrigerator for about seven days, ensuring the cap is on at all times.
It's important to note that shelf-stable oat milk may still be viable even after a month or more past its best-before date, but you have to check its integrity before consuming any.
Refrigerated Oat Milk
Unlike shelf-stable oat milk, refrigerated oat milk requires constant refrigeration. Although these types of milk also undergo pasteurization, this process does not involve high temperatures. Compared to shelf-stable milk, refrigerated milk only lasts a week after its best-before date.
Most refrigerated oat milk can be kept unopened for up to 8 weeks in the fridge, or as long as the manufacturer says. Once the carton has been opened, it can be kept for up to 5 days.
Fresh Oat Milk
Although homemade fresh oat milk tastes better than the rest, it also has the shortest shelf life. Refrigerated fresh oat milk lasts for a maximum of 3 to 4 days, as it starts to smell and taste weird after that period. However, since homemade oat milk does not contain emulsifiers or stabilizers, the oats and water will separate, but this does not mean that the oat milk has gone bad.
How To Tell if the Oat Milk Has Gone Bad
Fresh oat milk has a creamy, beige, off-white, or any color similar to cream. Changes in color could be caused by mold growing inside the storage container, which means you should throw away the carton. Most often, expired oat milk develops a yellow to dark brown color.
Change of Consistency
If you notice any thickening or slimy texture in your oat milk once you pour it into your glass, that indicates that you have expired oat milk. However, you should expect some separation between oat particles and water, so we recommend shaking the bottle before opening it to avoid confusion.
Fresh oat milk smells sweet and nutty, while bad oat milk smells rancid and sour. Once you notice this smell when opening the carton, the milk is probably spoiled.
Change in Taste
If you haven't noticed anything mentioned above, taste a small amount of the oat milk. Fresh milk tastes sweet, while spoiled oat milk tastes sour.
What Causes Oat Milk Spoilage?
Although time and storage are things we have to consider, bacterial contamination is the most common cause of milk spoilage. When bacteria come in contact with lactose, they convert it to glucose, galactose, and eventually lactic acid, which causes that sour taste and smell.
However, it's important to note that storage significantly impacts bacterial contamination. Refrigerators are bacteriostatic, which means they stop bacteria from growing. This keeps the oat milk fresh longer.
How To Store Oat Milk
Unopened Shelf-Stable Oat Milk
You should keep unopened shelf-stable milk in a cool, dry place away from heat. It's vital that the packaging stays intact to avoid any bacterial contamination.
Refrigerate the Oat Milk
Refrigerating oat milk is the most common way of prolonging its shelf life. Refrigerated oat milk lasts a maximum of 10 days.
Freeze the Oat Milk
You can freeze oat milk if you want to. Frozen oat milk lasts up to three months in the freezer.
Even though you can drink oat milk past its "best before" date, you shouldn't drink milk that has gone bad because it may contain bacteria that can make you sick or cause other digestive problems.
If you want to substitute oat milk for another non-dairy milk, you can use nut milk like almond milk, soy milk, coconut milk, hazelnut milk, and even rice milk.
Yes, you can use oat milk as regular milk or any animal milk alternative. It offers a sweet taste without a harsh scent and works well in baked goods and drinks like coffee and smoothies.
Yes. You only need to soak your rolled oats in water, blend them, and segregate the liquid from the oat pulp. You can add a little vanilla extract or maple syrup to enhance the taste, store it in an airtight container, and place it in the fridge.
Most commercially available oat milks contain added sugar to enhance the taste. If you're watching your blood sugar levels, find ones that are labeled "unsweetened oat milk."