Expiration dates are a part of our daily lives. When we shop at a grocery store, we check the dates on milk cartons to help determine if we can drink all the milk before it goes bad. We also know that milk can sometimes outlast the expiration dates that are printed on the carton. If our milk is sitting in the refrigerator, a couple days past due, but smells normal, we wouldn't hesitate to keep drinking until we are out, or it starts to go sour.
And that's all the dates really are, just guidelines for when the food may expire. The FDA doesn't mandate an expiration date on food goods:
"With the exception of infant formula, the laws that the Food and Drug Administration (FDA) administers do not preclude the sale of food that is past the expiration date indicated on the label. FDA does not require food firms to place “expired by”, “use by” or “best before” dates on food products. This information is entirely at the discretion of the manufacturer.
A principle of U.S. food law is that foods in U.S. commerce must be wholesome and fit for consumption. A “best by,” “use by” or expiration date does not relieve a firm from this obligation. A product that is dangerous to consumers would be subject to potential action by FDA to remove it from commerce regardless of any date printed on a label."
As a best practice, these dates helps consumers understand how fresh a product is. Generally, the fresher the food product, the better the quality. While these concepts generally hold true for food products, e-liquids have a shelf life that depend on a number of variables.
Flavorings sourced from natural sources will have a shorter life span than artificial ones. Some components, like PG, VG, or Nicotine may be cheaper and will start to degrade quicker than more expensive ingredients.
Most manufacturers on MVG will recommend juices be consumed within a year of bottling. What happens when we go beyond that year? Probably not much, but just like milk, there are a few things to consider:
Take a look at your juice. Does it look clear and free of particles? Smell your juice. Does it smell similar to when you first bought it? (flavor changes may occur due to steeping). How does it taste? Vape a small sample and see if it's worth keeping or dumping.
Our advice is to listen to your senses. While some articles state that nicotine and flavorings actually start to degrade after two years (not one), it is better to go with your gut. If the juice makes you feel uncomfortable, dump it and get a fresh bottle. If it seems okay, then it probably is. Use your best judgement and vape on.