What's the difference between rose water and rose hydrosol?
Rose water is distilled or deionized water infused with rose essential oils and rose absolutes to give it that signature fragrance.
Rose hydrosol is rose distillate, which is the water soluble fraction collected during the production of rose essential oil.
That definitely clears things up, right?
How essential oils (and hydrosols) are made
Let's talk about how essential oils, in this example, rose essential oil is made. Rose petals are collected and placed into a still. Let's walk through the pieces of a still. The still consists of:
- a pot for boiling oftentimes with a mesh separator to keep the plant pieces from settling to the bottom of the pot and burning
- a lid with a hole in a it
- a heat exchanger sits inside the hole in the lid and allows the steam to condense
- a collection vessel at the end of the heat exchanger to collect the condensed steam
Rose petals are placed either directly into the boiling pot or on the mesh separator/strainer. Deionized water is filled into the pot and the water is brought to a boil. As steam passes through the rose petals, it carries volatile compoundswithin the petals along with it into the heat exchanger. The rose infused steam then condenses inside the heat exchanger and is collected in the collection vessel.
At the end of distillation, the collection vessel contains both a layer of rose essential oil, a hydrophobic also known as lipophilic layer lying on top of rose distillate more commonly known as rose hydrosol as the bottom layer of the collection vessel.
These two are split with the rose essential oil being bottled as rose essential oil and the rose distillate or rose hydrosol is bottled as rose hydrosol.
The essential oil contains volatile oil soluble compounds from the rose petals and the hydrosol contains volatile water soluble compounds from the rose petals.
For roses, steam distillation yields about 0.02% essential oil and roughly equal weight of rose hydrosol, so if 5 pounds of rose petals are steam distilled, about 5 pounds of rose hydrosol is collected at the end of distillation.
Other names for rose hydrosol are rose hydrolat and rose essential water.
The rose hydrosol contains about 0.02% to 0.05% of aromatic compounds so is quite dilute compared with essential oils. For this reason, hydrosols are extremely mild and can be used undiluted on your skin.
You may be wondering where rose absolute and rose concrete play into this, so let's round out that part of the discussion before moving into rose water.
How absolutes, concretes, and resins are made
In the essential oil & hydrosol distillation we just talked about, water acted as a solvent. When anything other than water is used, we enter the space of absolutes, concretes, and resins.
Making an Aromatic Concrete
Concretes are made by soaking fresh plant material (petals, buds, stems, roots, peel) in an organic solvent (meaning the solvent contains carbon not that it's made organically... organic solvents are more hydrophobic (oil loving) than water). Common solvents are ethanol, hexane, and ethyl acetate.
At the end of the soak time, the petals are strained from the rest of the mixture and the solvent is removed from this liquid mixture through vacuum distillation.
This process uses essentially no heat or rather very low heat to keep the material from freezing during vacuum distillation. This prevents the volatile aromatic compounds from being pulled into the distillate.
Instead, the solvent by itself is collected as the distillate in a separate vessel, and all the aromatic compounds remain in the main vessel and are generally quite waxy and very nearly solid. For this reason, they're called a concrete.
Making an Aromatic Resinoid
Resinoids are made using dried plant material rather than fresh plant material. Otherwise, they're made the same as a concrete.
Absolute
The concrete or resinoid is dissolved in alcohol, specifically ethanol. Any undissolved solid or waxy material is separated from the liquid portion. The liquid portion is then subjected to vacuum distillation to pull off the ethanol, and this leaves behind an absolute. Absolutes are generally thick flowable liquids kind of like molasses. Some, like vanilla absolute are even solid at room temperature.
Yield from Essential Oil, Hydrosol, & Absolutes
It takes about 3750 pounds of rose petals to create 1 pound of rose essential oil. By comparison, it takes about 400 pounds of rose petals to create 1 pound of rose concrete. Even if the yield in creating the absolute from the concrete is only about 50%, rose absolute still requires much less petals than rose essential oil.
Rose Water
Rose water is made by adding rose absolute and perhaps a bit of rose essential oil to plain distilled water. Even though the rose absolute and rose essential oil are oily, hydrophobic solutions, they can dissolve into distilled water at low concentrations and with plenty of mixing.
Composition of Rose Essential Oil, Rose Absolute, and Rose Hydrosol
The composition of essential oils, absolutes, and hydrosols varies, and the ratios of compounds in each is of great interest for both perfumery and skincare.
Composition of rose absolute, rose essential oil, & rose hydrosol
Researchers found that phenylethyl alcohol is the main constituent of rose hydrosol accounting for nearly 80% of its composition. Citronellol and geraniol were the major compounds in both rose essential oil and rose hydrosol accounting for more than 55% of the volatile compounds in each.
Rose absolute contained higher levels of beta carotene and the vitamin E tocopherols alpha and gamma tocopherol compared to the essential oil and hydrosol. Rose absolute and rose essential oil both contain high levels of phenolic compounds, which are naturally occurring antioxidants.
Exploring the Alchemy of it all
Rose hydrosol and rose floral water are both renowned for softening skin and diminishing the appearance of pores. And, both rose hydrosol and rose floral water exhibit anti-inflammatory properties.
Because essential oils are sparingly soluble in water, floral waters like hydrosols are also very dilute making them less likely to cause any adverse reaction.
So, which is better?
Hydrosols fuse aromatherapy with herbalism consisting of both the water soluble fragrance compounds and also other water soluble compounds from the petals.
Hydrosols often maintain a more herbaceous aroma with a bit of crisp earthiness than their floral water counterparts. Because of their skin benefits and no known risk of causing skin sensitivities, hydrosols are widely used in Rain Organica's facial products.
You'll find rose hydrosol in all The Essentials product collection at Rain Organica, and Light Mist Toner in particular exhibits a fabulous natural fragrance imparted by the rose and cucumber hydrosols in that formula.
If you'd like to try a rose floral water, pick up Rain Organica's Rose Water Mist laden with rose floral water. This mist is more fragrant and intended as a body & hair mist. You'll likely notice an instant softness for your hair & body. You'll find Rose Water Mist works well as a linen spray, for misting towels and pillowcases.
Would you consider leaving a podcast review for The Alchemy of Things and sharing with a friend? I'd be so grateful for your time. Thank you for listening and for taking the time to leave a review.
Until next time,
References
Aromatic Natural Raw Materials
About the Author
Brandy's a formulation scientist and self-proclaimed health geek who loves hiking, gardening, bird-watching, and body boarding.
Her struggle with acne during her teens and 20s led to a holistic and healthy approach to skincare, embracing skin as an organ to be loved and cared for rather than a canvas to wage war on.
Since 2008, she's been developing all-in-one products for a simple routine at home, & Rain Organica started when her backpacking friends asked for a portable skincare routine to keep their skin healthy & happy on and off the trails.
You can try Rain Organica for yourself with The Essentials Kit, a complete skincare routine in just 3 steps.
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