Walnut oil is one of the great finishing oils — the kind of bottle that turns a bowl of leaves, a plate of pasta or a slice of banana bread into something you'd pay for. It's also one of the most misused: fried, left in a sunny cupboard, or bought stale. This guide covers what walnut oil tastes like, what's in it, how to use it well, and how to keep it at its best.

What is walnut oil?

Walnut oil is pressed from walnut kernels — in the best versions, cold pressed and left unrefined, so the oil keeps the full character of the nut. A good cold pressed walnut oil is pale gold with a deep, toasted, gently sweet aroma. Refined versions exist, but they trade away most of the flavour that makes walnut oil worth buying in the first place.

What does walnut oil taste like?

Rich and unmistakably nutty — toasted walnuts, a touch of sweetness, and a delicate, pleasantly bitter finish that keeps it from feeling heavy. It's more assertive than hazelnut oil, rounder than pumpkin seed, and it makes even a plain green salad taste deliberate.

What's in it?

Walnut oil is one of the richest everyday culinary sources of alpha-linolenic acid (ALA) — the plant form of omega-3 — at roughly 10–14% of its fatty acids, alongside a large share of linoleic acid and traces of vitamin E. That polyunsaturated profile is a blessing and a warning in one: it's what makes the oil nutritionally interesting, and it's exactly why walnut oil hates heat and light.

How to use walnut oil

• Dressings first. Walnut oil with sherry vinegar, honey and shallot is a bistro classic — the exact recipe is in our cold pressed dressing recipes.
• Bitter leaves and cheese. Chicory, radicchio or rocket with goat's cheese and pear — walnut oil ties the whole plate together.
• Over pasta and risotto. A thin drizzle just before serving, especially with mushroom or squash dishes.
• Roasted vegetables. Roast with a neutral oil, finish with walnut oil while everything's still warm — beetroot and green beans are the classics.
• Porridge and baking. A teaspoon over morning oats with honey; or swap it into banana bread and brownies where a nutty note belongs.

Why you should never fry with it

Those delicate omega-3 fats break down quickly under heat, taking the flavour — and the point of the oil — with them. Walnut oil belongs on food, not under it. When a recipe needs real heat, use a stable workhorse like high-oleic sunflower oil and add the walnut oil at the end; our smoke point guide explains which oil handles which job.

How to store walnut oil

This is the oil the fridge was made for. Unopened, a well-made walnut oil keeps for many months in a cool, dark cupboard — but once opened, oxygen starts its slow work. Cap it tightly, keep it in the fridge, and aim to finish the bottle within two to three months. If it ever smells like old paint or tastes harshly bitter, it has gone rancid: retire it. (A 250ml bottle over a litre is precisely so you finish it fresh.)

How to choose a good walnut oil

• Cold pressed and unrefined — the flavour lives in the unrefined oil.
• Single ingredient — 100% walnut, no blends.
• Dark glass and a clear best-before date — light and age are walnut oil's enemies.
• Trust the aroma — it should smell like toasted walnuts the moment you open it. Our Walnut Oil (250ml) is exactly that: one ingredient, cold pressed, dark glass.

Walnut oil vs olive oil

They're teammates, not rivals: olive oil is the everyday generalist, walnut oil the finishing specialist with the omega-3 edge and the nuttier voice. We've compared them properly — flavour, heat, cost and when to use each — in Walnut Oil vs Olive Oil.

Frequently asked questions

Can you cook with walnut oil?
Only gently, and ideally not at all — it's a finishing oil. Heat destroys its delicate fats and flavour.

Does walnut oil need to be refrigerated?
After opening, yes — the fridge meaningfully slows rancidity. It may thicken slightly when cold; that's normal.

Is walnut oil high in omega-3?
It's one of the richest common culinary oils in plant omega-3 (ALA) — roughly 1.5g in a tablespoon.

What does walnut oil go with?
Bitter leaves, goat's cheese, pear, beetroot, mushrooms, pasta, porridge and honey — anywhere a toasted-nut note belongs.

The short version

Buy walnut oil cold pressed and fresh, keep it in the fridge, and never let it near a frying pan. Used as a finishing oil — over salads, vegetables, pasta and even porridge — it does more per teaspoon than almost anything else in the cupboard.