Olive Oil Poached Tuna: The Confit Method, Step by Step
Olive oil poached tuna is tuna cooked slowly in a bath of warm olive oil until it turns tender, moist and silky, the method French cooks call confit. Done well, it tastes nothing like dry, overcooked fish: the low, even heat leaves the flesh soft enough to flake with a spoon, and the oil carries garlic, lemon and herbs right into it. Below is our own step-by-step method, written for this article in metric and US measures, with the two numbers most recipes leave out: the safe internal temperature for fish, and how long tuna kept under oil lasts in the fridge, both taken from the UK Food Standards Agency and the US food-safety agencies. We also cover which olive oil to use, and what to do with the oil afterwards.
For our own oil, see our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml).
The Short Answer
- To poach tuna in olive oil, cover thick tuna steaks in olive oil infused with garlic, lemon peel and herbs, and cook them gently with the oil held at about 70–80°C (160–175°F) until the centre of the fish is cooked.
- The US FDA and FoodSafety.gov give 63°C (145°F) as the safe internal temperature for fish, or flesh that is no longer translucent and separates easily with a fork. The UK Food Standards Agency uses the same visual test: flesh that has turned opaque and flakes easily.
- For four 2.5cm (1in) steaks, allow 600g (about 1⅓ lb) of tuna and 500–700ml (2–3 cups) of olive oil in a small, snug pan; cooking takes roughly 15–25 minutes.
- Cooked tuna kept under oil must go in the fridge, cooled within two hours. The FSA says eat leftovers within 48 hours; USDA guidance allows 3–4 days. Oil does not preserve fish, so never keep it at room temperature.
- A good, everyday extra virgin olive oil is the best choice: the oil never gets near its smoke point, and it flavours the fish and becomes a sauce you will want to eat.
- Sidr & Stone's olive oil is a single-estate, cold-pressed, unfiltered extra virgin olive oil from our own farm on the plains outside Marrakech, Morocco, sold in 500ml dark glass.
What Is Olive Oil Poached Tuna (Tuna Confit)?
Confit is an old preserving technique: food is cooked slowly while submerged in fat, then often stored in that same fat. Duck confit is the best-known example. With fish, the word is used more loosely for the cooking method alone: the tuna is poached, not fried, in oil kept well below the temperature at which it would sizzle.
The appeal is control. Water boils at 100°C and fish poached in it overcooks quickly; a hot pan sears the outside long before the centre is done. Oil held at 70–80°C cooks tuna slowly and evenly from edge to centre, so the whole steak reaches the target temperature at about the same time, with no grey, dry outer band. The result is closer to good tinned tuna in olive oil than to a grilled steak, only fresher and more tender. Our look at Rio Mare tuna covers what the oil is doing in the tinned version.
Thick, firm tuna works best: albacore, yellowfin or bigeye steaks about 2.5cm (1in) thick. Thin steaks cook through too quickly to benefit from the method. The same technique suits swordfish, halibut and salmon.
Ingredients
This serves four as a main course, or six to eight as part of a salad or sharing plate. We give grams first, with US measures alongside.
| Ingredient | Metric | US |
|---|---|---|
| Tuna steaks, about 2.5cm (1in) thick (albacore, yellowfin or bigeye) | 600g (4 × 150g) | about 1⅓ lb (4 × 5oz) |
| Fine sea salt, for the fish | 6g | 1 tsp |
| Extra virgin olive oil, enough to cover | 500–700ml | 2–3 cups |
| Garlic cloves, peeled and lightly crushed | 4 | 4 |
| Unwaxed lemon, peel only, in wide strips | 1 | 1 |
| Fresh thyme sprigs | 4 | 4 |
| Bay leaves | 2 | 2 |
| Black peppercorns | 3g | 1 tsp |
| Optional: dried chilli flakes | 1g | ½ tsp |
Equipment: a small, heavy saucepan or deep frying pan in which the steaks fit snugly in one layer, and a probe thermometer. The thermometer matters more than in most recipes: it tells you both the oil temperature and when the fish is done.
The Confit Method, Step by Step
- Salt the tuna. Pat the steaks dry and sprinkle them evenly with the salt on both sides. Return them to the fridge, covered, for 30 minutes. This seasons the fish all the way through and firms the surface slightly. Keep the fish chilled until you are ready to cook; the FDA advises never leaving seafood out of the fridge for more than two hours (one hour above 32°C / 90°F).
- Choose the pan and measure the oil. Lay the steaks in the pan: they should sit in one layer, close together but not touching. Pour in enough oil to cover them by about 1cm (½in). A snug pan is the main way to keep the quantity of oil down. Lift the fish out again and set it aside on a plate in the fridge.
- Infuse the oil. Add the garlic, lemon peel, thyme, bay, peppercorns and chilli to the oil. Warm over the lowest heat until the thermometer reads 80°C (175°F), then hold it there for 10 minutes. The garlic should soften without colouring; if it starts to brown, the oil is too hot.
- Add the tuna. Pat the steaks dry and lower them gently into the oil. The temperature will drop by several degrees. Adjust the heat so the oil settles and stays between 70°C and 80°C (160–175°F). You should see, at most, a few lazy bubbles around the fish, never a sizzle.
- Poach slowly. Cook for about 8–12 minutes, then turn each steak carefully with a fish slice and cook for a further 6–12 minutes. Thickness and starting temperature vary, so use the times only as a guide and the thermometer as the test.
- Check the centre. Insert the probe into the thickest part of one steak. It is done when the centre reaches 63°C (145°F) and the flesh has turned opaque and separates easily into flakes when pressed with a fork, the doneness signs given by both the FSA and FoodSafety.gov.
- Rest and serve. Lift the tuna out onto a warm plate, or into a dish if you plan to keep it, and let it rest for 5 minutes. Serve it warm, at room temperature within the two-hour window, or chilled, with a spoonful of the strained oil over the top.
Safe Temperatures: Oil Versus Fish
Two temperatures matter in this recipe, and it helps to keep them apart. The oil temperature controls how gently the fish cooks. The fish temperature, taken in the centre of the thickest piece, tells you whether it is cooked to the official guidance. The table below sets out the figures we checked against the agencies' current pages.
| Checkpoint | Temperature | Source / note |
|---|---|---|
| Infusing the oil | 80°C (175°F) | Our method; hot enough to draw out flavour without browning garlic |
| Poaching the tuna | 70–80°C (160–175°F) | Our method; gentle, even cooking |
| Fish, done (US) | 63°C (145°F) | FDA (145°F) and FoodSafety.gov: or flesh no longer translucent, separating easily with a fork |
| Fish, done (UK) | Visual test | FSA: flesh turns opaque and separates easily with a fork |
| General "fully cooked" core (UK) | 70°C for 2 minutes | FSA general guidance, or 65°C for 10 minutes, 60°C for 45 minutes |
| Fridge | 0–5°C (40°F or below) | FSA: set between 0 and 5°C; FDA and USDA: 40°F or below |
| Reheating leftovers | 74°C (165°F) / steaming hot | USDA: 165°F; FSA: steaming hot throughout, reheat only once |
Sources, read 13 October 2026: the FSA's Cooking your food and How to chill, freeze and defrost food safely; FoodSafety.gov's Safe Minimum Internal Temperatures; the FDA's Selecting and Serving Fresh and Frozen Seafood Safely; and USDA FSIS's Leftovers and Food Safety.
The objection: "Restaurants serve confit tuna pink"
Many do. Some chefs poach tuna in oil only until the centre is warm and still rosy, well below 63°C, for a texture closer to rare steak. That is a choice made with very fresh, carefully handled fish, and it sits outside the official guidance above. Our method cooks the tuna through, which still gives a far moister result than grilling or baking because the heat is so gentle. If you choose to cook it less, know that you are departing from the FSA and FDA advice, and do not serve undercooked fish to anyone who is pregnant, elderly, very young or has a weakened immune system.
Storing Tuna Under Oil in the Fridge
One of the pleasures of tuna confit is keeping some for later, packed into a jar under its own oil. Done safely, it makes excellent salads and sandwiches for the next day or two. The rules are simple:
- Cool it quickly. Let the tuna and oil cool, then refrigerate within two hours of cooking. The FSA advises cooling cooked food and getting it into the fridge within one to two hours; USDA's limit is two hours.
- Pack it in a clean container. Put the tuna, whole or in large flakes, into a clean glass jar or lidded dish. Strain the cooled oil through a fine sieve and pour it over to cover. Discard the garlic and herbs.
- Keep it cold. Store at 0–5°C, or 40°F (4°C) or below in US terms.
- Eat it soon. The FSA says to eat leftovers within 48 hours or freeze them; USDA FSIS allows leftovers 3–4 days in the fridge. We follow the shorter window: eat tuna kept under oil within two days.
Why the oil does not preserve it. Covering fish in oil keeps air off the surface and slows drying, but it does not make the fish shelf-stable or stop bacteria growing. Cooked tuna under oil is a perishable fridge food, like any other cooked fish. Never keep it in a cupboard or at room temperature, and do not confuse homemade confit with commercially canned tuna, which is sealed and heat-processed in a factory. Our guide to garlic-infused olive oil explains the same principle for homemade infusions.
Cold or reheated? Tuna confit is best eaten cold or at cool room temperature. The FSA notes that leftovers can be eaten cold if they were cooked properly, cooled and refrigerated within two hours. The oil will set and turn cloudy in the fridge; this is normal, and it melts back to clear in 15–20 minutes at room temperature. If you do reheat it, the FSA says to heat food until steaming hot throughout and only reheat once; USDA uses 74°C (165°F). Bear in mind that reheating will firm up the tuna.
Which Olive Oil to Use for Poaching Tuna
The most common question about this recipe is whether extra virgin olive oil is wasted on it. It is not. At 70–80°C, the oil is far below the temperature at which extra virgin olive oil starts to smoke, so it holds its character, and the oil becomes part of the dish: you spoon it over the fish, dress salads with it and dip bread in it. Our guide to olive oil at high heat covers what happens at much higher pan temperatures.
| Oil | For poached tuna |
|---|---|
| Fresh, medium-fruity extra virgin | The best all-round choice; flavours the fish without overwhelming it |
| Robust, bitter and peppery extra virgin | Works if you like a bold result; can dominate delicate albacore |
| Mild, delicate extra virgin | Good for a subtle result; let the lemon and herbs lead |
| Refined, "pure" or "light" olive oil | Cooks the fish perfectly well, but adds little flavour to a dish where you eat the oil |
| An old or rancid oil of any grade | Avoid; stale notes go straight into the fish |
A practical approach is to poach in a good everyday extra virgin and save your most expensive bottle for drizzling over the finished plate. Whichever you choose, the usual buying checks apply: the extra virgin grade, a harvest or best-before date, dark glass or a tin, and a named origin. Our guide to choosing a quality olive oil sets them out, and types of olive oil for cooking compares the grades.
The objection: "That is a lot of oil to use once"
It is less wasteful than it looks. A snug pan keeps the quantity down, and the oil is not discarded: strained, it is a flavoured cooking oil and dressing. Because it has been in contact with fish and fish juices, treat it as part of the dish rather than as fresh oil. Keep it covered in the fridge and use it within the same two days, for dressing the tuna, tossing through pasta or white beans, or making a quick mayonnaise-style sauce. Do not pour it back into the bottle.
How to Serve Olive Oil Poached Tuna
- Niçoise-style salad: large flakes of tuna over green beans, boiled new potatoes, soft-boiled eggs, tomatoes, olives and leaves, dressed with the poaching oil and lemon juice.
- White beans: warm cannellini beans with parsley, lemon zest and a spoonful of the oil, the tuna laid on top.
- Pasta: tossed through hot spaghetti with capers, chilli and the strained oil.
- Sandwiches: on crusty bread with roasted peppers, rocket and a few olives, a fresher version of the classic tuna sandwich.
- As it is: warm from the oil with a green salad and bread to mop up.
For other ways to flavour fish with olive oil before cooking, our olive oil marinade guide gives a base ratio for fish.
Why Sidr & Stone
In olive oil poached tuna, the oil does three jobs: it cooks the fish, it carries the flavour of the aromatics, and it ends up on the plate as the sauce. That makes the character and freshness of the oil matter, and the oil is the part of this dish we can speak for. Sidr & Stone's extra virgin olive oil comes from one place, our own farm on the plains outside Marrakech, and we control every step from tree to bottle.
- Single-estate: Sidr & Stone's olive oil comes from our own family-owned farm near Marrakech, Morocco, with no blending across origins.
- Rain-fed: the trees are not irrigated; they take what the season gives.
- Organically grown: no synthetic fertilisers, pesticides or herbicides are used (not yet certified; certification is in progress).
- Single harvest: each batch is small and limited, picked when the fruit is ready; once it is gone, it is gone until the next harvest.
- Cold-pressed within hours of harvest: to protect flavour, aroma and polyphenols.
- Unfiltered extra virgin: minimally processed, so a little natural sediment at the bottom of the bottle is normal.
- 100% natural: a single ingredient, olive oil, with nothing added.
- Dark glass with a gold label: 500ml bottles that protect the oil from light.
- 10% of profits to charity: a Sidr & Stone commitment across every product.
- Fulfilment in the UK, EU and US.
We will not tell you that you need a premium single-estate oil to poach tuna; any sound extra virgin will cook it well. What we will say is that our oil is single-estate, rain-fed, organically grown and cold-pressed within hours of harvest, and that the product page carries the details of the current batch, so you can judge it for yourself before it goes into the pan or onto the plate.
Frequently Asked Questions
What temperature should the oil be for poaching tuna?
Hold the oil between 70°C and 80°C (160–175°F). That is hot enough to cook the tuna through in 15–25 minutes, and gentle enough that the fish stays moist and the oil never sizzles or browns the garlic.
How do I know when olive oil poached tuna is done?
Check the centre of the thickest steak with a probe thermometer: the FDA and FoodSafety.gov give 63°C (145°F) for fish. Without a thermometer, use the visual test given by the FSA and FoodSafety.gov: the flesh turns opaque and separates easily with a fork.
How long does tuna confit keep in the fridge?
Keep it covered in oil in a clean, sealed container at 0–5°C (40°F or below), refrigerated within two hours of cooking. The FSA advises eating leftovers within 48 hours; USDA allows 3–4 days. We recommend eating it within two days.
Can I use extra virgin olive oil to poach tuna?
Yes. At 70–80°C, extra virgin olive oil is well below its smoke point, and because the oil flavours the fish and is eaten as a sauce, a good extra virgin gives a noticeably better result than a refined oil.
Is Sidr & Stone's olive oil good for poaching fish?
Yes. It is a single-estate, cold-pressed, unfiltered extra virgin olive oil, so it has the character to flavour the tuna and to be spooned over the finished dish. Many cooks poach in an everyday oil and finish with a special one; ours works for both.
Can I reuse the oil after poaching tuna?
Yes, within limits. Strain it, keep it covered in the fridge and use it within the same two days for dressings, pasta or beans. It has been in contact with fish, so treat it as part of the dish, not as fresh oil.
Where can I buy single-estate extra virgin olive oil?
Our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml) is available directly from the Sidr & Stone website, currently to pre-order as a limited single-harvest batch, with fulfilment in the UK, EU and US.
Is olive oil a medicine?
No. Olive oil is a food, not a medicine. It has a long traditional history — including being honoured in the Prophetic Sunnah — and a substantial body of modern research, particularly around polyphenols, cardiovascular health, and the Mediterranean diet pattern. It can be a worthwhile part of a healthy routine, but it does not cure diseases and is not a substitute for medical care. Be cautious of any olive oil marketed with specific disease-cure claims.
Final Thoughts
Olive oil poached tuna rewards patience more than skill. Infuse the oil, keep it between 70°C and 80°C, and let the thermometer tell you when the centre reaches 63°C (145°F) and the flesh flakes. What you get is tuna that is moist all the way through, with a ready-made sauce in the pan.
Treat the leftovers as the fresh, perishable fish they are: into the fridge within two hours, under oil in a clean jar, and eaten within two days. Choose an oil you would happily eat on bread, because by the end of the meal, you will have done exactly that.
If you want a single-estate oil for the pan and the plate, our Cold-Pressed Single-Estate Extra Virgin Olive Oil - Marrakech (500ml), rain-fed and cold-pressed within hours of harvest, is available to pre-order now, with fulfilment in the UK, EU and US.
Our extra virgin olive oil is grown organically on our own single-estate farm on the plains outside Marrakech: we control every step from tree to bottle, and no synthetic pesticides, herbicides or fertilisers are used. It is not yet certified organic — certification is in progress, and we will publish it as soon as it comes through.
Disclaimer: This article shares a home recipe and general food-safety information drawn from the UK Food Standards Agency, the US FDA, USDA FSIS and FoodSafety.gov pages as read on 13 October 2026; guidance can change, so check your national food-safety agency for the latest advice. Cooking times are starting points and depend on the thickness of the fish. Fish is a common allergen. Olive oil is a food, not a medicine, and is not a substitute for medical treatment of any condition. For any health concern, consult a qualified medical professional.