Yes.

Tallow skincare can go bad.

The fact that something is “natural” does not suspend chemistry.

There are two different issues worth understanding:

oxidation and microbial contamination.

Anhydrous products

A true balm made without water is relatively inhospitable to bacterial and fungal growth compared with a water-based cream.

That doesn't mean it lasts forever.

The fats themselves can oxidize over time.

Heat, light, oxygen and repeated contamination can speed deterioration.

A rancid fat usually announces itself through a noticeable change in smell.

Water changes everything

Once a formulation contains water, preservation becomes a much bigger issue.

Water provides an environment in which microorganisms can grow.

This is why you cannot judge the safety of a skincare formula simply by looking at whether the ingredient list seems “clean.”

Formulation chemistry matters.

Store your skincare like skincare

Generally:

• keep the lid or pump closed
• store away from excessive heat
• don't leave it baking in direct sunlight
• don't introduce water into jars
• use clean hands
• follow the stated shelf-life directions
• stop using a product that develops an unusual smell, colour or texture

Your bathroom doesn't need to become a sterile laboratory.

Just don't actively try to turn your moisturizer into a microbiology project.

What if tallow melts?

Tallow is temperature-sensitive.

A warm environment may soften or melt an anhydrous tallow product.

That isn't necessarily spoilage.

It is fat behaving like fat.

Texture can change after melting and resolidifying, particularly in whipped products.

Again:

texture change and spoilage are not automatically the same thing.

What about ours?

Most of what we make is anhydrous and lasts about a year.

The exceptions are the ones with water in them — Copper Peptide Salve, Magnesium Body Lotion and Mag Stick. Those are best used within six months of purchase.

Trust the product, not a universal internet rule

A pure tallow balm and an emulsified tallow cream do not have identical shelf-life considerations.

Follow the directions for the specific product in front of you.

“It's tallow” is not enough information.

New to tallow? Start with Tallow for Skin: What It Is, What It Does, and Who It’s For.