Generally speaking, the thing we want these ingredients to be are a product of distillation. When plant matter is distilled it creates two end products—essential oils and a hydrosol/distillate/hydrolat/floral water/aromatic water. The oil floats to the top and is separated off. The remaining water part seems to have many names, but generally speaking, this is what it should be.
Products sold with these names are not always products of distillation, though. It isn’t uncommon to purchase something with one of these names that is actually an essential oil that has been solubilized in water. These faux hydrosols are typically given away by their foam—if you shake one you’ll get some lather. This is because of the inclusion of a solubilizer, which is technically a surfactant. They can also be given away by an SDS (safety data sheet), which can reveal a solubilizer and essential oil as part of the ingredients of the product.
So, how much does it matter? This is somewhat up to you. They both smell nice and will contribute the scent of the plant in question, so in that sense they can be somewhat interchangeable. As a formulator you really should know what you’re working with, so if you think you’re working with a true hydrosol but it’s actually essential oil solubilized in water, then you don’t know exactly what you’re using (if you’re particularly concerned with keeping things natural the solubilizer may not meet your natural standards, either).
The aromatic chemical compound composition of a hydrosol is different from its partner essential oil, so if what you’re working with is actually an essential oil solubilized in water, that’s not quite the same experience as a true hydrosol. Learn more here.
If you’re getting a faux hydrosol you’re probably paying quite a premium for the essential oil. There is likely less than 1% essential oil in that “hydrosol”, and if that’s what you want to use then, you it’s worth investigating if purchasing the essential oil would be a more cost-effective option.
Something else you should be aware of: are the hydrosols you are purchasing preserved or not? If not, you may want to add a preservative when your hydrosols arrive, especially if you know you won’t use it terribly quickly. 0.3% Liquid Germall™ Plus will do the trick. If you manufacture huge batches of something and can drain a bottle of hydrosol the first time you open it you can probably skip adding your own preservative. I also always keep my hydrosols in the fridge.
Posted in: Ingredients