Making infused oils, from tarragon to chilli, rosemary to lemon, is an easy way to transform your cooking, and reduce food waste in the process! Food writer Malou Herkes shows you how.
Infusing a bottle of oil, whether it’s fresh herbs or garlic, citrus or chilli is a simple way to add flavour to your cooking. Sage oil on fried eggs is transformative, as is a kick of chilli oil on your last-minute stir-fry dinner. Rosemary oil works magic with roast potatoes, and garlic infusions are good with just about everything.
Infused oils are a clever way to cut food waste and preserve precious flavour: that wilting bunch of leftover herbs, the lemon peel from a squeezed lemon or those last couple of chillies are a good place to start. Any fresh or dried herbs, from sage to marjoram, oregano to tarragon, infuse wonderfully with oil. You could also try garlic, whole chillies or chilli flakes, and whole spices, such as peppercorns, star anise, cinnamon or cardamom. Mix and match your flavourings too; try sage and peppercorn, rosemary and lemon or thyme and garlic, for starters.
Should I dry out my flavourings first?
You can use either dried or fresh ingredients to infuse oil. Dried ingredients will have a more concentrated flavour and will therefore give you a more intensely flavoured oil. By drying them out you’re getting rid of any moisture, which means there’s less chance of your oil developing moulds so you can store your oil for longer. To dry out your flavourings, spread them out on a tray and place in a low oven (100ºC) for a couple of hours.
That said, you can also infuse oil with fresh ingredients (see below). If you do this, it’s best to use it within a couple of weeks. Straining out your flavourings before bottling will help to preserve your oil for longer. Garlic, however, is particularly prone to developing the dangerous botulism bacteria so make sure you strain it out and use the oil within a week.
Does it work with any type of oil?
Some recipes recommend using a good-quality, mild-flavoured oil, such as sunflower or vegetable. That way the taste of the oil doesn’t compete with the taste of the herbs. Saying that, I find olive oil works really well especially if you prefer using it for drizzling over finished dishes.
How to make infused oil
Prepare your flavourings. If using fresh ingredients, wash them well and make sure they’re as dry as possible. For lemon-infused oil, scrub 2 unwaxed lemons in hot water and dry thoroughly, then use a sharp paring knife or vegetable peeler to remove the zest in nice, long strips. It’s the yellow part of the peel you want, not the bitter white pith underneath. If necessary, use a sharp knife to scrape away any unwanted pith.
Place the lemon peel (or other flavourings) and 500ml of olive oil in a saucepan and gently warm over a medium heat. Allow it to heat up, but not so hot that bubbles start to appear on the surface. The idea is to heat the oil just enough to encourage the lemon zest to release its natural oils into the liquid. Too hot and the oil will start to cook it. This applies to any other infused oil, from fresh herbs to garlic. Set the pan aside and leave it to cool to room temperature.
Use a funnel to strain the oil into a clean, sterilised bottle. Discard the lemon peel (if using dried ingredients, you can leave them in). Great for dressing salads, for drizzling over cooked greens and fried eggs, for sprucing up cooked grains or in pesto.
How long does infused olive oil last?
If using fresh ingredients, try to use it within a few weeks. If using dried ingredients, it’ll last for months. Store out of direct sunlight. Keep fresh garlic oil in the fridge.