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A single red rose among green bushes.
Different therapeutic properties of rose oil have been investigated in human studies and the most important of them are analgesic and anti-depressant activities.

Diluting your flower scented oil

We have included the dilutions that we used, and our observations, in the table below.

An example: Roses

Dilution Volume of flower oil (mL) Volume of new olive oil (mL) Scent description
None 50 0 floral
1 in 2 10 10 floral
1 in 4 5 15 slightly floral & fruity
1 in 6 5 25 fruity, not floral
1 in 8 5 35 fresh, fruity
1 in 10 5 45 fresh, fruity

You can find a blank copy of the table in the additional PDF file at the bottom of this step. For each dilution, remember to take a new volume of the flower oil you have made and dilute it with new olive oil.

Let us know how your flower extraction went!

When you are done we would love to see your results! Upload a picture of your table and the oil you have made using our open Padlet (we have included some examples from previous courses to help inspire you) or the Twitter or Instagram hashtag #FLchemistry, telling us what flowers you have chosen.

Having filled in the dilutions table, try and provide a quick summary of your results here so we can explore commonalities and variations. For example, you might also like to consider using an alternative to olive oil, such as almond oil, jojoba oil or castor oil, to name just a few.

What’s in a name?

The dilution of a fragrance explains the difference between a perfume, cologne and toilette. Depending on the concentration, usually in ethanol (or a mixture of ethanol in water), it gets a different name:

Eau de Cologne: Typically composed of 2–5% perfume oils

Eau de Toilette: A light spray composition with 5–15% pure perfume essence

Eau de Perfume: Typically contains 10–20% perfume essence

Perfume: Contains 15–40% pure perfume extract with a thicker oilier consistency

Adding ethanol separates out the odours so that you can distinguish them. A perfume oil has a medley of smells. Smelling it would be like listening to an orchestra play all the notes in a symphony at the same time. You might register that you are smelling something sweet, but not that it’s lemon, then jasmine, and finally vanilla. Its diluted nature makes the smell much more enjoyable.

Take the taste test

To show the importance of smell on what we eat, close your eyes, squeeze your nose tightly so you cannot breathe through it, eat a jelly bean & deduce its flavour. You will likely struggle. As you can only taste the sweet sugar this is not enough information to tell the flavour. Normally, your brain receives signals from both your mouth and nose, allowing you to recognise whatever tasty treat you are chewing.

Still not convinced? Well get a piece of chocolate and some table salt. Pinch your nostrils and put some chocolate in your mouth. Start chewing, still holding your nose, and do not swallow. You are unlikely to taste anything. Now, with the chocolate still in your mouth and your nostrils still squeezed, take a pinch of salt and put this in your mouth. With your nose still sealed, you will be able to taste the salt (as it is registered by your tongue), but not the chocolate. Now let go of your nose and the flavour of the chocolate will come through. Hopefully this taster demonstration will build up your appetite for learning more – we will revisit this topic in week 3.

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This article is from the free online course:

Exploring Everyday Chemistry

University of York