How is lemon hydrosol made?

The lemon tree is a shrubby plant from the Rutaceae family, primarily cultivated in the Mediterranean basin. Originally, this tree grew in the Middle East. Its introduction to the West dates back to the 4th century BC, driven by Alexander the Great. During antiquity, the lemon was mainly used for its culinary properties and its anti-nausea action. Its use was then extended to other areas, notably therapeutic and cosmetic.

Lemon hydrosol, also known as lemon water, presents itself as a colourless liquid, sometimes slightly opalescent, with a characteristic fresh and lemony scent. It is a natural ingredient used in the production of various skin and hair care products.

It is crucial to differentiate between lemon hydrosol and lemon juice. Indeed, the latter is highly acidic and strongly photosensitising due to its concentration in furocoumarins. On the other hand, lemon hydrosol is a gentle, non-photosensitising treatment suitable for all skin types.

Lemon water is attributed with numerous properties, among which are anti-inflammatory and anti-microbial virtues. Indeed, it contains several active ingredients that have a detrimental effect on bacteria, including limonene and pinenes. Others help to alleviate pain and facilitate the healing of minor wounds. Finally, lemon hydrosol is known to have a unifying effect on the complexion and to give a healthy glow.

Lemon hydrosol is obtained through a process of steam distillation (hydrodistillation) of lemon peels. Here is how this process unfolds step by step:

1. Lemon peels are placed in a still connected to a boiler, in which water vapour is produced.

2. This steam is then directed into the still that houses the lemon peels. The increase in temperature triggers the release of the essential oil they contain. The temperature inside the still must be slightly above 50°C, which is the flash point of lemon essential oil. Beyond this temperature, it begins to evaporate, allowing the steam to become enriched with the essential oil.

3. The water vapour, carrying the essential oil, is then cooled in a coil submerged in a refrigeration tank. This change in temperature liquefies the vapour.

4. Water and oil, of different densities, are then separated in a separator. The lower phase consists of water lightly charged with essential oil, this is known as lemon hydrosol. The pure essential oil, less dense than water, makes up the upper phase of the liquid.

Although the concentration of active ingredients in lemon hydrosol is lower than that of lemon essential oil, it remains a valuable commodity. It notably contains limonene, pinenes, linalool, geranial, and traces of vitamin C. Hydrosols are generally quite delicate and certain precautions must be taken regarding their preservation. They are highly sensitive to light and heat, as well as oxidation and microbial infections.

In order to maintain the properties of lemon hydrosol, it is crucial to store it in a dry and cool place, shielded from heat, moisture, and light. We therefore recommend keeping it in an amber bottle, in the refrigerator, combining darkness and coolness, which helps to limit bacterial growth. After opening, the lemon hydrosol should be used within six months thereafter.

Typology has incorporated thelemon hydrosol (INCI name: Citrus Limon (Lemon) Fruit Water), obtained through hydrodistillation of European lemons, into two treatments:

• The hyperpigmentation serum is a treatment concentrated in alpha-arbutin, a brightening active ingredient. It also contains lemon hydrosol, which works in synergy with alpha-arbutin to enhance its effects. Daily application of this serum helps to reduce the appearance of brown spots and delay their onset.

• The antioxidant face cream contains lemon extract combined with vitamin C (INCI name: Sodium Ascorbyl Phosphate) and helps to combat oxidation phenomena and even out the complexion. It is also enriched with vegetable glycerin for its humectant properties.

• FACCIOLI L. & al. Integration of pressurized liquid extraction and in-line solid-phase extraction to simultaneously extract and concentrate phenolic compounds from lemon peel (Citrus limon L.). Food Research International (2022).