Herbal Oils

INFUSED OILS

Having a good stock of infused (or ‘macerated’) herbal oils is more or less essential. Often they can be used on their own, perhaps with an essential oil or two added. Infused oils can be made from dried herbs, but always try to take the opportunity to use fresh herbs – cheaper and so much better. Never underestimate the value of a good herbal oil on the skin – there’s often no need to do anything more complicated. However, they’re also commonly combined in more complex external preparations such as ointments and creams.

It’s a common question to ask what vegetable oil to use for making infused oils. In essence we require three major things from a fixed oil: that it’s stable enough to be heated without degrading too much; that it’s light enough to spread well; and it’s not too smelly or otherwise unpleasant to use. Olive oil is particularly stable and can stand moderate heating, is nourishing, cooling in temperament and has good spreading qualities (but can cause the user to smell like salad dressing!) Where your chosen herb is particularly delicate, such as lemon balm, or where you want to show off the colour, such as Marigold, Sunflower oil is light, stable & cheap. Always use organic oils, as pesticides tend to be fat-soluble. If you want to use cold-pressed oils, take into account they can be expensive, some of their benefits can be lost on heating, and they are more likely to invite infection. On the other hand, they will be absorbed better and if used later to incorporate into creams will emulsify better. The choice is yours!

To infuse herbs, they will need to be comminuted in the same fashion as for making tinctures – this is largely a matter of common sense. Petals, flowers, seeds and small leaves may be infused whole. Larger leaves, stems, etc. should be chopped fairly coarsely – a fine mulch will not mix well enough with the oil to infuse properly, and will increase the chances of the whole thing going rancid. For the same reason, never pack in the herbal material tightly – let it find its own space.

Whatever method you use, you will need to filter the oil before bottling. First pass through a kitchen sieve, then either through a paper coffee filter, or place a ball of cotton wool not too tightly at the base of the cone of a suitably large funnel for the oil to seep through (start by pouring gently, otherwise the cotton wool will simply float to the top). Either method can easily block with debris after a while, so you may need to use a fresh filter paper or wodge of cotton wool from time to time.

There is always a potential for herbal oils to go rancid or ‘off’, particularly if you’re using fresh herbs – the oil has become infected, either whilst it’s being infused, or later during storage. Here are some tips:-

• When using bulky fresh herbs, allow them to wilt in a warm place for 2-12 hours to reduce the water content before proceeding. (But be careful with aromatic herbs that you don’t loose too many volatiles this way).
• When using the sun infusion method, it will help to place a teaspoon or two of salt at the bottom of the jar, which will absorb any settling water.
• The final product should be clear – if it’s cloudy, there’s water in it, so heat gently to evaporate it off.
• If you’re worried, heating the final product (made by whatever method) to 70°C for 20 minutes will effectively sterilise it.
• Check your oils in stock often. If any water globules or debris settle at the bottom, decant the oil off from it before it’s too late. If the oil develops an ‘off’ smell, discard it and learn from experience.

Sun Infusion Method

Steeping herbal oils in the sunshine is a wonderful and magical process – the classic product, and also the most unproblematical, is the famous St John’s Wort Red Oil. Partially fill a large glass jar (an old confectioner’s sweet jar is ideal) with organic olive oil, or sunflower oil if you prefer. Pick fresh St John’s Wort tops in full flower, complete with a few distal leaves, and drop them in – don’t pack too tight, let them find their own space, and do make sure the herb is fully covered by the oil. Shake or tap the jar to remove any trapped air bubbles. If you don’t have much of a supply of the herb, there’s no reason why it can’t be topped up until full over a period of a few days. Screw on the lid and leave the jar on a sunny windowsill (or just out in the garden – why not!) for at least two weeks until your green olive oil and yellow flowers have produced an amazing blood-red oil. Strain, filter and bottle. For a more concentrate result, you can simply strain the oil and return it to the jar, adding a second batch of fresh flowering tops to steep in the sun again, before proceeding to the filtration stage.

The sun infusion method is only used for fresh herbs, and is then only suitable for very light material with a low water content – it’s commonly also used for Mullein flowers, Lemon Balm leaves, and Pot Marigold petals (whole Marigold flower heads must be wilted first to avoid problems).