Can brownie mix go bad?

In this brief study, we will answer the question “Can brownie mix go bad?” We will also go into the shelf life and storage practices while handling it.

Can brownie mix go bad?

Yes, brownie mixes do go bad because the elements in the mixture may lose quality over time. For instance, leaving agents and baking soda can lose effectiveness, and fat can break down resulting in rancidity.

Furthermore, brownie mixes can go bad if stored improperly. This product is shelf-stable due to its low moisture values (9% or below) [1]. 

However, they are also highly hygroscopy, implying that brownie mix can easily absorb moisture from the surroundings if stored improperly [1]. 

A moisture increase will favor clustering and microbial growth, as shown by Abdullah and others [2], who determined that moisture contents higher than 10% promote mold development in wheat flour.

What is the shelf life of brownie mix?

Unopened, the shelf life of brownie mix is 6 to 12 months. After opening, the brownie mix should be consumed within a few days and should be kept tightly closed in a cool, dry place.  Always stick to the best-before date described on labels.

How to tell if the brownie mix has gone bad?

The signs that your brownie mix has gone bad include clumps, the appearance of off-flavors or off-odors, mold growth, and insect infestation.

Furthermore, if the leaving agent or baking soda is no longer effective, you will notice your dough will not grow properly.

Clustering indicates the occurrence of moisture pickup, given that brownie mixes are highly hygroscopic [1]. Mold growth could also be a sign of moisture increase.

Molds are perceived as bluish-green spots on the powder, sometimes with a cotton-like appearance. Moldy products are preferentially discarded because certain species of mold can produce toxic compounds.

Given that brownie mix is high in sugar, it can also be the target of insect infestation. 

Off-odors and off-flavors could be the result of undesired chemical reactions, such as fat oxidation, as chocolate is rich in fat. 

How to store brownie mix?

Maintain your unopened brownie mix in a cool, dry, dark place, for instance, in a pantry or kitchen cabinet. Keep in mind that moisture absorption can ruin your mixture.

If you have leftovers, to keep the mixture safe, remember to seal it while not in use. Place the mixture in a freezer bag or airtight container if the packaging cannot be sealed easily. 

If you do not want to use it right away, you may store the combination in the freezer, where it should survive for a bit longer. Usually, frozen foods last for 3 to 4 months.

To freeze, put the brownie mix in the bag or container and flatten the mixture to ensure that it freezes evenly. 

Keep the container lid or bag tightly covered at all times to ensure that the brownie mix is completely protected from freezer moisture.

To thaw it, just transfer the frozen bag or container from the freezer to the refrigerator and leave it overnight or until completely defrosted.

Can you use a brownie mix that has expired? 

You can use an expired brownie mix as long as you are sure that it has been stored properly over its shelf life, and that you do not detect any sign of spoilage or damaged package, which could indicate insect infestation.  

Brownie mixes are low moisture and low water activity products [1]. Therefore, harmful microorganisms will rarely grow if the mix is stored properly during its shelf life.

They are usually given a best-before date, which means that after the printed date, the quality may start to drop quickly, but it is still safe to consume [3].

For instance, it is possible that past the best-before date, the baking soda and leavening agents do not work properly, resulting that your brownie will not grow as expected. 

Fat from chocolate can also degrade, giving a rancid flavor and aroma.


In this brief study, we answered the question, “Can brownie mix go bad?” We also explained the shelf life and storage practices to be done while handling it


1. Leiras MC, Iglesias HA. Water vapour sorption isotherms of two cake mixes and their components. International Journal of Food Science & Technology. 1991;26(1):91-7.

2. Abdullah N, Nawawi A, Othman I. Fungal spoilage of starch-based foods in relation to its water activity (aw). Journal of Stored Products Research. 2000;36(1):47-54.