Hydrosols

Inert Storage Containers

If the hydrosols are shipped in metal containers, you will want to decant them immediately. Water causes metal to rust. Although aluminum flasks with a phenol-resistant coating are acceptable, they are expensive, and are rarely used for hydrosols except in small retail quantities. Unlined aluminum is unacceptable since, like essential oils, hydrosols may interact with the metal.

Most often hydrosols are shipped in plastic containers. The best plastic containers are made of Nalgene. This is a totally inert plastic, available in a variety of densities, but it is quite expensive. I have never had any problems with leaving the hydrosols in Nalgene in storage. You can also fit taps to these containers, making decanting easier and circumventing the necessity of frequently opening the vessels to pour off small amounts. Rigid plastics are better than softer plastics, as they are less likely to react with the contents.

Many bottle suppliers have a good range of high quality, phenol-resistant plastics that are suitable for shipment and storage of hydrosols. Glass is the ideal medium for transporting hydrosols, and hydrosols seem to do best in cobalt glass. 

However at this point cost must be factored in; weight is a consideration in shipping, and glass is breakable, heavy and expensive. Users must make their own decisions.I recommend selling small quantities of hydrosol in glass. Anything over 500millilitres (one-half-liter) should be packaged in a high quality rigid plastic, and I usually advise customers to decant into a glass if feasible.

Generally, if you are storing in a plastic other than Nalgene, you should try to keep your stock rotating. An option is to bottle into plastic to order, minimizing the concerns. Remember, we are not talking about oils here.Hydrosols do not contain the chemical constituents of oils that can melt plastic, Styrofoam, varnish, or paint. No hydrosol is that concentrated, and the percentage of oil that hydrosols contain is too small to worry about. So in most cases, the danger of storing hydrosols in plastic is only marginally greater than storing a mineral water in plastic.

Reference: Hydrosols-The Next Aromatherapy: Suzanne Catty