Herbal distillates, also known as floral waters, hydrosols, hydrolates, herbal waters, and essential waters, are aqueous products of hydrodistillation. They are colloidal suspensions of essential oils as well as water-soluble components obtained by steam distillation or hydrodistillation (a variant of steam distillation) from plants/herbs. These herbal distillates have uses as flavorings and cosmetics (skin care). Popular herbal distillates for skincare include rose water, orange flower water, and witch hazel. Rosemary, oregano and thyme are very popular hydrosols for food production.
Herbal distillates are produced in the same or similar manner as essential oils. However, essential oils will float to the top of the distillate where it is removed, leaving behind the watery distillate. For this reason the term essential water is an apt description. In the past, these essential waters were often considered a byproduct of distillation, but are now considered an important co-product. The produced herbal waters are essentially diluted essential oils at less than 1% concentration (typically 0.01% to 0.04%). Several factors, such as temperature and an herb's growth cycle, impact the characteristics of a distillate, and therefore influence the timing of the distillation. Rosemary, for example, should be distilled in the peak of summer before it flowers.
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Cosmetics and toiletries makers are finding many uses for herbal distillates. Distillates are also used as flavorings and curables. Herbal distillates have been used historically as a topical agent for cosmetics and medicinal use. Since herbal distillates are less concentrated than essential oils, they are more suitable for some situations, such as for the use of those who are sensitive, such as the elderly or young children.
White tea, rose and witch hazel distillates have become popular for skincare, and there have been many studies into the benefits of these practices. Some studies show that topical use of herbal distillates has been shown to protect fibroblast cells from hydrogen peroxide induced damage. This is caused by the high polyphenolic content and high activities in antioxidant assays. Additionally, there are many medicinal uses for herbal distillates based on their metal concentrations. Rose water and Orange blossom distillates have been found to be high in calcium. Researchers hypothesis that these distillates could be used as a calcium source for those who cannot digest animal calcium. Orange blossom and rose water also have levels of Selenium that would provide the daily recommended dose to decrease cancer rates. Rose water, Crataegus distillate, Peppermint distillate, Pussy willow distillate, have also been shown to have high levels of zinc. Zinc has been found to prevent skin disease and stomach irritation.
There has been numerous studies done to prove the antibacterial activity of herbal distillates. Hydrosols of anise, cumin, oregano, summer savory and black thyme have been shown to decrease bacteria growth in incubation. In particular, oregano and summer savory hydrosols are active against at least 15 different bacteria strains. Since this antibacterial activity occurs naturally, it can be used to prevent the deterioration of food, especially in organic farming. It is also safer for consumers and handlers of these products.
The science of distillation is based on the fact that different substances vaporise at different temperatures. Unlike other extraction techniques based on solubility of a compound in either water or oil, distillation will separate components regardless of their solubility. The distillate will contain compounds that vaporize at or below the temperature of distillation. The actual chemical components of these orange herbal distillates have not yet been fully identified, but plant distillates will usually contain essential oil compounds as well as organic acids and other water-soluble plant components. Compounds with a higher vaporization point will remain behind and will include many of the water-soluble plant pigments and flavonoids.
Because hydrosols are produced at high temperatures and are somewhat acidic, they tend to inhibit bacterial growth but not fungal growth. They are not sterile, and should be kept refrigerated to preserve freshness. Herbal distillates degrade over time and will degrade faster than essential oils, which are more stable and will degrade slower. Small-scale producers of hydrosols must be particularly aware of the risk of bacterial contamination and take steps to prevent it. Despite concerns that there may be significant amounts of heavy metals in popular herbal distillates, this has not shown to be the case.
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