An infused oil differs from an essential oil both in its qualities and in the method by which it is made. Whereas an essential oil is extracted directly from the plant and nothing else is added to it, an infused oil is made by placing the plant material - usually leaves or petals, but sometimes stalks are included - in a container of bland, unperfumed oil. This is kept in a warm place for two to three weeks, or until the base oil has absorbed all the perfume from the plant material. The petals or leaves are removed as they turn brown, and can be replaced by fresh batches until the base oil has attained the required strength of perfume. As well as the perfume of the plant, the base oil will by then have absorbed a great many of the plant's therapeutic properties.
This method has been in use for many thousands of years, long pre-dating the making of essential oils. In oriental and mediterranean civilisations, the pots were simply stood in the sun until the process was complete, but in the British Isles, unless we have an exceptionally hot summer, some additional source of warmth needs to be provided, such as an airing cupboard or a shelf above a boiler or other fairly constant source of heat. Some people stand the jar in a tray of water and heat the water, but this does not give such a good oil as the slower and more traditional method.
Because of its simplicity, and the fact that no expensive equipment is needed, this method provides anybody who has a supply of suitable fresh herbs or flowers available with the opportunity to make excellent massage oils at very little cost. Such oils share most of the properties of the essential oil from the same plant, but there is not a hundred-per-cent correlation. The infused oil may not have every one of the properties of the essential oil, but on the other hand, it may have absorbed other substances from the plant which are not present in the essential oil. They are quite complex substances, and should not be looked on merely as a 'poor relation' of essential oils. Although it is quite safe to take your knowledge of the corresponding essential oil as a guide to the properties and uses of an infused oil, you might also like to read a little more in books about medical herbalism to learn more about infused oils.
These oils are sometimes also known as Floral Oils if they are made from the petals, or Herbal Oils if they are made from any other part of the plant.
If you would like to experiment with making your own infused oils, take a large clean jar, preferably wide-mouthed, and fill it about one-third full with petals or leaves. Fill the jar almost to the top with almond oil, grape-seed, sesame, sunflower-seed or other good quality bland oil, then cover the top of the jar as tightly as you can to exclude the air which can quickly turn the oil rancid. Put the jar in an airing cupboard, on a shelf above your central-heating boiler, or an Aga — or put it in the sun if we have a really hot spell. In this case, bring the jar indoors at night and put it out again if the sun is sufficiently hot the following day. When the petals begin to turn brown, remove them and put in a fresh batch, and repeat this two or three times until your oil is strong enough. Then strain out any little bits of plant debris and bottle the oil, capping it tightly. It will last for a few months if stored away from light and air.