The short answer: for lemon-infused olive oil, warm the finely peeled zest of 2 to 3 unwaxed lemons in 250 ml olive oil on the lowest heat for 10 to 15 minutes. Let it cool, strain it and keep it in the fridge. Made with fresh zest, use it within 4 days. Made with dried zest, it keeps about a month. Never add the juice.
Lemon-infused olive oil tastes like a squeeze of lemon that never goes watery. A few drops lift grilled fish, green beans, hummus or a plain bowl of pasta. Use the zest, not the juice. All the fragrant lemon oil sits in the yellow skin. The juice is mostly water and acid, and it never mixes into oil. It sinks, turns cloudy and shortens the life of the jar.
| At a glance | |
|---|---|
| Time | 25 minutes, plus cooling |
| Ratio | Zest of 2 to 3 lemons per 250 ml (1 cup) oil |
| Heat | Lowest setting, no bubbling |
| Keeps | Fresh zest 4 days, dried zest about 1 month, in the fridge |
Ingredients
- 250 ml (1 cup) mild olive oil
- 2 to 3 unwaxed lemons
- Optional: a pinch of dried thyme, or 5 black peppercorns
Why unwaxed? Many lemons are coated with a thin layer of food wax to keep them shiny. The wax sits right on the zest. Buy unwaxed lemons, or scrub waxed ones under hot water and dry them well.
How to make lemon-infused olive oil
- Peel. Wash and dry the lemons completely. Peel the yellow zest in thin strips with a vegetable peeler. Leave the white pith behind, because it tastes bitter.
- Warm. Put the zest and the oil in a small pan on the lowest heat. Warm it for 10 to 15 minutes. The oil should smell strongly of lemon, with no sizzle at all.
- Cool. Take the pan off the heat and let it cool completely, so the zest keeps giving its flavour.
- Strain. Pour the oil through a fine sieve into a clean, dry jar. Press the zest lightly.
- Chill. Label the jar with the date and put it in the fridge.
The dried-zest version that keeps longer
Fresh zest still holds some water, so the oil should be used within 4 days. If you want a jar that lasts a month, dry the zest first.
- Spread the strips of zest on a baking tray.
- Dry them in the oven at its lowest setting, about 80 to 90 °C (175 to 195 °F), for 1 to 2 hours, until they snap.
- Or leave them on a plate in a warm, dry room for 2 to 3 days.
- Use the dried zest of 3 lemons per 250 ml oil and follow the same method.
Dried zest gives a rounder, less sharp lemon taste, closer to candied peel.
Slow-infused with the NOIDS Herb Lab
For the deepest flavour, infuse the dried zest slowly. Put the oil and zest in the Glass of the NOIDS Herb Lab, under the MAX mark. Cover it with the Dish Lid, place it in the Main Body and turn the Rotary Control to Oil. The cycle holds 100 °C (212 °F) for about 120 to 180 minutes and then cools by itself. Strain it through the Filter Set once the Glass is cool.
How to use lemon oil
- Drizzle over grilled fish, prawns or chicken.
- Toss with steamed green beans, asparagus or broccoli.
- Finish a bowl of hummus or a lentil soup.
- Make a quick dressing: 3 parts lemon oil, 1 part vinegar, salt.
- Use it in olive oil cakes for a gentle citrus note.
Other citrus oils
| Citrus | Zest per 250 ml | Good with |
|---|---|---|
| Orange | 1 large orange | Beetroot, duck, chocolate cake |
| Lime | 3 limes | Tacos, rice, avocado |
| Grapefruit | ½ grapefruit | Fennel salad, white fish |
For more citrus in baking, our recipe for orange extract uses the same zest. For herbs and chili, see the complete guide to infused olive oil.
Common mistakes
- Grating instead of peeling: finely grated zest is hard to strain and leaves specks that cloud the oil. Use wide strips from a peeler.
- Wet lemons: water drops on the skin end up in the oil. Dry the lemons completely before you peel them.
- Too much heat: the zest browns, the oil tastes bitter and the bright lemon note is gone. Keep the heat as low as it goes.
- Zest left in the jar: it looks pretty, but it carries water and keeps flavouring the oil until it turns bitter. Strain it out.
Storage
- Fresh zest oil: in the fridge, closed, and use it within 4 days.
- Dried zest oil: in the fridge, and use it within about a month. Penn State Extension allows up to 3 months; we use the shorter time.
- Freezer: either version keeps 3 months in an ice-cube tray.
- Olive oil turns cloudy in the fridge. That is normal and clears at room temperature.
Questions
Can I use lemon juice to make lemon-infused olive oil?
No. Juice is water and acid, so it does not blend with oil. It sinks, clouds the oil and makes it spoil faster. All the lemon fragrance is in the zest.
How long does lemon-infused olive oil last?
With fresh zest, 4 days in the fridge. With dried zest, about a month in the fridge. Both keep about 3 months frozen.
Why does my lemon oil taste bitter?
There was white pith on the zest, or the heat was too high. Peel only the yellow layer and keep the heat at its lowest.
Is lemon-infused olive oil the same as agrumato?
Not quite. Agrumato is made by crushing whole lemons together with the olives at the mill. Homemade lemon oil is plain olive oil flavoured with zest afterwards. Both taste of fresh lemon.
