Are you sick of losing protein bars to spoilage? Or worse – not knowing how to label your bar with an appropriate expiration date? We’ve got some information that will help
you learn exactly what shelf life is and how best to create a recipe that will last. We’ve even included some information on the different kinds of shelf life product testing available.

What exactly is shelf life?

Let’s take a brief look at the 3 categories of variables which collectively comprise shelf life:


In any protein bar, the aesthetics are the first element to begin degrading. We’ve
all seen a protein bar left out too long that has become as solid as a rock. Other considerations include the taste and texture, both of which can be negatively impacted if sold past shelf life specification.


The term rancidification refers to the process by which fats, oils, and lipid compou-
nds chemically decompose; this is important for protein bar shelf life as well as other foods because nearly all of them contain fat. When oxygen and light are allowed to interact with food products, this process begins.
Oxygen permeation is best mitigated through airtight, metallic foil packaging.

Yeast & Mold Growth

The water in protein bars or other foods can significantly shorten shelf life due to promoting yeast and mold growth. When water evaporates off the surface of a protein bar, it provides room for yeast and mold colonies to begin growing on the bar itself. This is why ingredients like dried fruit are typically preferred over water-heavy alternatives like applesauce in most protein bars recipes.
Nitrogen flushing the packaging can increase shelf life by reducing oxygen needed for mold growth

How Do I determine and test shelf life?

Element Bars coordinates with a certified 3rd party testing facility to measure and monitor each of those factors during the production of their protein bars. There are a variety of tests available to measure these different characteristics of shelf life. Let’s examine several of the tests Element Bars regularly use:

Water Activity

Water Activity is a proxy test that measures the amount of water that evaporates off the surface of a protein bar. If it is below the threshold where yeast and mold can grow, the product will usually have a long shelf life (9+ months).

Accelerated Test

The protein bars are placed in an “ideal” state for yeast and mold growth, which enables time-lapse measurement over 400% more quickly than normal, enabling you to simulate a year’s worth of sitting on a shelf in just a few months. This test works well for predicting yeast and mold issues, but not as well for concerns of rancidity or aesthetics.

Real Time Test

True to its name, the lab places the bars in a controlled environment for the specified time, testing it regularly. The lab usually execute both yeast and mold evaluations at each regular test, and also administer a peroxide test to measure rancidity. Real time tests are the gold standard in terms of shelf life testing, but performing them obviously takes a *long* time. Many organizations run this test in parallel with other tests, such as the accelerated or water activity tests discussed earlier, to allow the product to get to market in a reasonable time.