Preparing Bluefin Tuna

Chef slicing bluefin tuna

Dinko’s Southern Bluefin Tuna is a fresh, healthy and flavourful meal choice.

But for the inexperienced cooks among us, it can be a daunting task to prepare and cook this delicacy.

We talked to Carl Semmler, tuna connoisseur and cooking enthusiast, about the best ways to store, prepare and cook Southern Bluefin Tuna so that novice cooks can enjoy the best eating experience.

Chef cutting a big chunk of Tuna

Storing tuna

While fish is always best served fresh, it can be difficult to plan, purchase and cook accordingly.

Carl always uses Dinko’s Bluefin Tuna, because of their innovative super-freezing technology, which maintains the taste and nutritional value, while preserving the fish for longer.

“Dinko’s snap freezing technology really holds the freshness and flavour… you know it will be as good as it gets.

Using this super-freezing method, tuna can be stored in the freezer for up to three months.

When thawing, it is important to follow a few simple steps to ensure the quality of the fish is being maintained:

  1. Keep tuna in Dinko Seafoods cryovac bags in a refrigerator while defrosting.
  2. Once defrosted, remove from cryovac bags and pat dry.
  3. For any excess or leftover tuna not consumed, wrap in Japanese wasabi paper, store in a sealed container and place in the refrigerator.
  4. Consume within 5 days of defrosting.

Preparing tuna

Sliced Tuna Sashimi on a wooden board


Carl gave us some tips on preparing sashimi at home.

“When preparing sushi or sashimi, it is really important to use the freshest piece of tuna you can find.

Because it is so delicate, I make sure the tuna is still slightly frozen when I’m slicing it, so it doesn’t tear or fall apart.

Carl’s favourite dish is a simple sashimi recipe.

“I just cut the tuna into small cubes, add sriracha, kimchi juice, a pinch of shichimi pepper and sesame oil.

Then I finely chop some spring onion and throw in some sesame seeds and mix it all up. You can enjoy it on anything from steamed rice to crusty bread… Yum!

Try another sashimi recipe here.

Organic free range pan seared tuna


Pan-searing is a classic tuna preparation method that involves briefly cooking the outside of the fish, while leaving the inside raw. According to Carl, this is where many cooks can make mistakes.

When searing tuna, the most common mistake is overcooking. Because we generally cook chicken and other meats, there is often a fear of undercooking.

But in the case of tuna, you really need to be confident in the quality of the fish and only sear it for 30-45 seconds on each side.”

Prefer a firmer texture? Try dry-curing it before cooking. Simply rub the tuna with kitchen salt and place it in an airtight container for 30 minutes, before rinsing with cold water.

If you’re feeling adventurous, why not try our tuna steak recipe with chargrilled vegetables, caper berry and lemon cream.

Close up of chargrilled tuna steaks cooking in a griddle pan


For the perfect grilled tuna, it’s important to remember to not let it stick to the grill. Marinating before cooking not only gives extra flavour, but adds moisture to the dish to help avoid sticking.

If you don’t have time to marinate, simply brush the tuna with oil and grill over very high heat for a couple of minutes on each side.

As with any tuna method, it’s important not to cook a tuna steak past medium-rare, and don’t let it rest after searing.

Baked tuna steak with vegetable garnish


Baking tuna for too long is the biggest mistake you can make with this method, as it can dry out the fish and take away from the naturally delicious flavours, Carl explains.

The worst thing you can do with any tuna is to overcook it, and this goes for when you’re baking too. If you are baking, preparing a mornay or something like that, just remember not to cook for too long.”

A simple strategy for perfectly baked tuna is to marinate your fish first, then remove the fillets, brush with oil and place in a sheet pan.

Bake at high heat (around 230C) until seared on the top and pink on the inside, around 8-12 minutes (cooking time will depend on the thickness of the fillet).