Why Gummies Harden in Their Packaging

You can spec a high-quality, recyclable, competitively priced pouch and still watch the product inside it degrade. Gummies that harden in storage are a classic example, and the natural reaction is to scrutinise the film. The real issue is a mismatch between the barrier rating and what the product actually needs.

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Quick answer: Gummies harden when the packaging does not block enough oxygen and moisture for that specific formulation. Barrier is not one-size-fits-all: a high-water-content gummy needs a far tighter barrier than a dense, compact one. A vacuum-metallised film is often not enough for a sensitive blend, in which case a foil-based laminate, which blocks oxygen and moisture almost completely, is the right tool. The fix is to spec barrier from the product outwards, not from the material in.

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READ MORE: What’s the difference between Recyclable vs. Recycled? Read our guide here. 

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Why a high-barrier pouch can still let a product degrade

"High barrier" is relative. A metallised barrier delivers strong oxygen and moisture protection and works well for many products, but it is not absolute. If a formulation is more sensitive than the film can hold, the product degrades on the shelf even though the packaging looks more than adequate on paper.

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For gummies, the variable is moisture and oxygen sensitivity, and it swings widely by recipe. A high-water-content or actives-heavy gummy can demand far more protection than a dense, compact one. The barrier rating has to be matched to the product's actual permeability needs, not assumed from a material's reputation.

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Barrier is a number, not a label: OTR and WVTR

The way to make this concrete is to specify against two figures: oxygen transmission rate (OTR) and water vapour transmission rate (WVTR). Those describe how much oxygen and moisture a structure lets through, and they are what you match to the product, rather than a loose "high barrier" description. Working from the product's real sensitivity is the only reliable way to land a structure that performs in the field.

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When a product needs foil

For the most moisture-sensitive formulations, foil is sometimes the only structure that delivers. Foil is a true barrier: it blocks oxygen and moisture almost completely, holding the product stable across its full shelf life even in challenging storage. 

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Grounded usually designs foil out of its structures, because foil generally is not accepted into soft plastic recycling streams. But preventing product waste can be the more important sustainability criterion, and the structure can still be built with maximum recycled content around the foil core. 

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Switching the barrier rarely means changing your fill line; the pouch format, zipper, and artwork can carry through, with only the laminate underneath changing.

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How this played out in practice

A therapeutic skincare company with a line of mushroom-based gummies started on a sound-looking metallised barrier and watched the gummies harden in storage anyway. The blend simply needed more protection than the metallised layer gave. Moving to a foil-based laminate, built with maximum recycled content, ended the hardening across the range, with no change to the fill line or pack format.

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How to get it right

• Spec from the product, not the material: Start with how the actual formulation behaves in real storage, then choose the barrier that holds it.
• Use OTR and WVTR, not "high barrier": Match real transmission numbers to the product's sensitivity.
• Weigh the foil trade-off honestly: Foil carries an end-of-life cost, but preventing spoilage can be the better call; maximise recycled content around it and confirm the recycling pathway in your markets.

READ MORE: Five sustainability metrics for you to consider. 

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What this means for you and your brand

Spec your barrier from the product outwards. Oxygen and moisture thresholds vary by formulation, and a barrier that protects one gummy can let another harden, so a material's reputation is no substitute for matching it to how your product actually behaves.

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Sometimes that points to a material you would rather avoid. Foil needs industrial recycling, but preventing product waste can be the more defensible sustainability call, and maximising recycled content keeps the trade-off honest. If you are seeing shelf-life problems you cannot explain, talk to our team about matching barrier to formulation.

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Frequently asked questions

Why do gummies harden even in high-barrier packaging?

Because the barrier may not be tight enough for that formulation. High-moisture gummies need a much stronger oxygen and moisture barrier than dense ones, and a metallised film can fall short where foil does not.

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What is the difference between a metallised barrier and foil?

A metallised layer is a thin metal coating that improves barrier but is not absolute. Foil is a true barrier that blocks oxygen and moisture almost completely, which some moisture-sensitive products require.

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How do you choose the right barrier for a supplement?

Work backwards from the product. Test how the actual formulation behaves in real storage, then specify the barrier that holds it, rather than assuming a strong general-purpose film will cover every SKU.

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