Why the shelf is dark glass

What the shelf holds

Sixty containers from about 15 ml to 120 ml, every one glass, with 186 closures. Thirty of the sixty are light protective, and the colors tell the story: amber, blue and frosted alongside clear. Forty-seven of the sixty are boston rounds.

Glass because the carrier is a solvent

Alcohol at tincture strength sits against its container for a year or more, and essential-oil-bearing extracts are harder still on plastics. Glass is inert and the question does not arise, which is why the archetype excludes plastic entirely for this use.

Dark because light degrades botanicals

Plant constituents are light sensitive and the product has a long shelf life sitting on somebody’s shelf, often in a bathroom or a kitchen rather than a cupboard. Amber is the traditional answer and blue is chosen as often for how it looks as for what it blocks.

Amber and blue are not equivalent

Both reduce transmitted light and they do it across different parts of the spectrum, with amber generally the more complete barrier. Choosing blue for the shelf presence is a legitimate decision as long as it is a decision rather than an assumption that any colored glass is the same.

Clear has a real use

Where the product is meant to be seen, or where sediment is part of the story you are telling about minimal processing. The trade is a shorter honest shelf life and storage advice on the label.

Small, because the dose is small

A 30 ml bottle at a milliliter a day is a month, which is the natural repurchase cycle for this category. Larger formats look like value and spend longer open, which works against a light-sensitive product.

References