A beginner's guide to kaoyu

Everything you wanted to know about roast fish but were afraid to ask

If you've never eaten kaoyu (烤鱼), Chinese roast fish, you're missing out: the whole fish, grilled and braised in sauce alongside fresh vegetables, is hearty, fresh, delicious and really easy to get in Beijing.

Whether you're a kaoyu novice or just want to brush up on how and where to make the most of this simple and satisfying dish, our guide has you covered.

What is it?
Kaoyu literally means roast fish – but in Beijing the term has come to refer to a multi-stage cooking process for freshwater fish that was originally developed in Chongqing.

Fresh fish from the Yangtze River were butterflied, dry-grilled and then served in a shallow brazier with sliced vegetables, chillies, herbs and flavoured oils. The grilling prevents the spice and seasoning from overpowering the fish while the brazier keeps the dish hot and lets the natural juices cook the fresh vegetables.

The modern version retains the two-step genius of the original with the improvement of a variety of add-ons and seasonings for every palate.

Why eat it?
Something we hear all the time in the capital: 'Beijing doesn't have a sea, why would I eat seafood here?' That may be true for some choicer aquatic victuals, but wild river fish and their farm-raised brethren are tasty, fresh, very often local and affordable.

Kaoyu joints are everywhere and once you know the ropes you've got a solid, reasonably priced evening plan for anywhere in the city. It's fun for groups of fve or six people, and we bet your friends aren't bored with  it. Get stuck in!

How to order

Sold? Here's how to order.

1. Get a really fresh fish

When ordering whole fish, the simplest and easiest way to make sure you are getting a fresh one (and not the bottom of the barrel) is to ask to see your fish.

Even small kaoyu places have tanks and serve only live, whole fish to order as the fish weighs more when alive and can fetch a higher price per jin (around 500g). Ask your server to bring the fish out or ask if you can go through to the back and pick one yourself.

Remember, you're looking for vibrant scales (or bright skin in the case of catfish that don't have scales), plump wet eyes and some healthy movement. There shouldn't be any foul or sour odours, but a hint of fishiness isn't a bad thing.

2. Pick the right fish

Most kaoyu restaurants will have several types of fish available, representing a range of flavours - from mild and light suited to fish beginners and simple sauces to very boldly flavoured flesh suited to fish lovers and strong, spicy seasoning - and of bone types.

Jiangtuan yu 江团鱼

1.5-2.5kg; 60-70RMB/jin

Why? It has mild and light flavour with thick, strong bones spaced far apart. Very easy to eat.

With silvery white scales, the channel river fish, or long snout catfish, is prized for its fatty fresh and mild flavour. Best in winter and spring, this is a good candidate for milder sauces, fresh mushrooms and green veggies. With large bones, it's easy to eat and well suited to first-timers.

Cao yu 草鱼

1.5-2.5kg; 30-40RMB/jin

Why? It has mild flavour, which tastes of the waves and spray, with thick, strong bones spaced far apart. Very easy to eat.

The grass carp is the most widely available and reasonably priced fish. They reproduce quickly and grow fat on a diet of aquatic plants, giving them a clean, mild flavour. Grass carp is the classic match for dried and fresh chilli sauces with spring onions, golden mushrooms and cauliflower.

Qingjiang yu 清江鱼

1-3kg; 45-55RMB/jin

Why? Mild flavour, that tastes of the waves and spray, with medium-sized strong bones, medium spacing. So you need to take your time.

The Qingjiang river fish has supple, flaky white flesh and a mild flavour. This fish can only thrive in very clean water so its flesh and skin are often bright and have a clean fish flavour that can stand up to spice and Sichuan peppercorns. It's our personal favourite and also beginner-friendly.

Hei yu 黑鱼

1.5kg and up; 35-45RMB/jin

Why? Bold flavour, benefits from strong seasoning and spice with medium-sized strong bones, medium spacing. So you need to take your time.

The 'black fish' (northern snakehead) is a ferocious carnivore. Its diet and vigorous lifestyle results in a nutrient-dense fish with a strong flavour and denser flesh. The black fish's strong flavour makes it ideal for spicier sauces and crisp slices of lotus root, peanuts and sliced potato.

3. Choose your sauce

The sauces offered by many places will vary by brand, with some having their own names for their signature version, but the basics remain the same.

Mala (麻辣), spicy hot chillies with numbing peppercorns;  xiangla  (香辣), fresh and dried chilli; suanla (酸辣), sour vinegar and hot chillies;  yuxiang (鱼香), ginger, garlic, sugar and spring onion.

Mala is certainly the most challenging for those unfamiliar with the effect of the Sichuan peppercorn, and yuxiang is the mildest crowd pleaser. Although all kaoyu arrive in chafing dishes of red oil, don't be alarmed: the oil's bright red colour is less an indicator of spice than the presence of fresh chillies, which really contain the real face-melting heat of the dish.

How to eat a whole fish with chopsticks

Many people aren't used to eating whole fish with bones, but there are a few tricks that make it a breeze – even with chopsticks.

• Have a plan of attack, clear off the toppings and scope out a good view of the piece you want to grab.

•  Take stock of the direction of the bones. If the chef has butterflied the fish with the spine in the middle, both sides will radiate out; if the spine is on one side, only one side with radiate out and the centre will be all flesh.

• Approach from above, using your chopsticks to break the piece free and then slide it along the grain of the bones.

•  Take smaller bites from pieces of fish on your plate or over rice, this way any stray bones that made it to your plate have a chance to get screened before slipping down the hatch.

• Savour the fruits of your labour! It's not as easy as carving up a steak, so enjoy the various favours and textures by combining different toppings with bites of fish.

For a list of our favourite kaoyu restaurants, hit 'Read more'.

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