Into the Mix: How Packaging Materials Impact Shelf Life and Potency for Infused Beverages
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For any consumer beverage, compatibility between the product and its packaging is a make or break issue. Most industries have it figured out, but for infused cannabis and CBD beverages, achieving compatibility is a complicated and often overlooked challenge.
In fact, loss of potency due to incompatible packaging has been an issue for the infused beverage industry since day one. Engineering the perfect fit for any product takes time. For example, scientists benefit from decades of research to determine what can liner material is best for beer, and which is best for tomato sauce. Cannabis and hemp infused beverages are a new product category, and we are still in the process of building this knowledge.
Therefore, producers of infused products need to understand interactions between different packaging materials and the beverage’s cannabinoid emulsion – the dispersion of cannabinoid droplets throughout a liquid.
Back to chemistry class
Cannabinoid emulsions are designed to overcome a fundamental principle in chemistry: the antagonism between oil and water. Whereas beverages are water-based, THC and CBD are extracted in oil form. Working at the molecular level, emulsions keep infused beverages from looking like salad dressing.
In more scientific terms, emulsification is the process by which one liquid (oil) is blended and suspended within another immiscible liquid (water). A compound called an emulsifier facilitates this process. The emulsifier has two distinctive parts – one hydrophobic, and one hydrophilic – that will arrange itself between the water and oil boundary and stabilize it. The goal is to infuse oil (cannabis in this case) into a beverage to create a seamless and reliable experience for the consumer.
But before the new product can be trusted and accepted by customers, the emulsion must also be compatible with its packaging. Let’s take a closer look at the three most commonly used vessels in beverage packaging, and the obstacles that they pose for compatibility with infused products.
Currently, glass bottles are the most common vessel used for infused beverages. A major contributing factor is that glass is made from SiO2, which is hydrophilic. Since the emulsion droplets contain cannabinoids, which are hydrophobic, they will naturally repulse from the hydrophilic glass, maintaining the even dispersion of droplets throughout the beverage. Glass bottles, therefore, generally yield strong results for potency shelf life.
A note on regulations: glass bottle packaging of infused beverages is regulated differently from state to state. For example, in California cannabis packaging cannot show the actual product, so extra steps must be taken to mitigate the transparency of glass bottles. This hurdle in the production process may lead some companies to explore alternative vessel types.
Other than packaging regulations, there are numerous reasons why a company might prefer aluminum cans over glass bottles. The cans’ shape might be more economical for shipping and storage; the manufacturing process fits in with existing production chains; and many markets prefer the aesthetic of cans.
Unfortunately, this choice comes with a new set of emulsion obstacles. Like glass, aluminum is hydrophilic. However, storing liquid in hydrophilic aluminum can lead to any number of issues, including corrosion, flavor interference, and instability. To solve this problem, aluminum cans contain an internal liner of thin hydrophobic polymer, made with major components such as polyethylene (PE), polypropylene (PP), Bisphenol A (BPA), or other types of polymers.
This is a good solution for most beverages. But for cannabinoid emulsions, hydrophobic oil at the center of the emulsion droplet will be attracted to the hydrophobic liner, eventually attaching to it. This happens faster when there is carbonation in the can. This effect can reduce the potency shelf life of infused beverages, leading to widespread ineffectiveness and inconsistencies.
An emulsion must therefore be able to both deliver cannabinoid homogeneity throughout the beverage as well as maintain a controlled interaction with the can liner. It’s possible, through emulsion engineering, to create a stable and reliable canned infusion. But what is required is significant expertise on the part of the emulsion provider, with a deep understanding of emulsion structure, and the ability to fine tune its hydrophobicity and surface property.
Polyethylene terephthalate (PET) bottles, commonly used for water and soft drinks, are rarely used for infused beverages.
Why? Firstly, PET is a hydrophobic polymer, which means that an emulsion destined for a plastic bottle would require the same fine-tuning as for a lined can. Secondly, PET bottles are more difficult to store. Under circumstances of prolonged heat exposure, PET bottles can leach levels of a contaminant called antimony that are deemed unsafe by the Environmental Protection Agency. But thirdly, and likely most important, most PET bottles cannot withstand the pasteurization required for cannabinoid beverages. Under high pressure and temperature, bottles can warp, ruining the product entirely.
PET bottles are therefore the most vulnerable to shelf life issues of the three major vessel types; though, in terms of potency loss, they are on par with polymer-lined aluminum cans.
In addition, a loss profile will also vary according to the beverage base and pasteurization method. With so many variables at play, and in an industry where it’s vital to show consistency and trustworthiness, the best infused beverages will source emulsions that are customized and engineered to meet the highest scientific standard.
Harold Han is the founder and chief science officer at the Oakland-based infusion technology company Vertosa.