What is katsu sauce?

In the UK, katsu sauce usually means katsu curry sauce: a mild, smooth and slightly sweet Japanese style curry sauce poured over breaded chicken and rice. In Japan, katsu sauce means something else, a thick, fruity brown sauce called tonkatsu sauce. Both are served with crumbed cutlets, which is why the names get mixed up.

Katsu curry sauce vs tonkatsu sauce

Katsu curry sauceTonkatsu sauce
What it isA mild curry gravyA thick, tangy brown condiment
Tastes likeWarm spices, onion, a touch of sweetnessFruity, sweet and sharp, like a richer brown sauce
How it is usedPoured over the cutlet and riceDrizzled straight onto the cutlet
Where to buy itJars and block mixes in the world food aisleBottles from Japanese grocers, and some larger supermarkets
Our guideKatsu curry sauce mixTonkatsu sauce

If a recipe asks for one, the other will not do the same job. A UK recipe for chicken katsu curry almost always means the curry sauce.

What katsu curry sauce tastes like

Think of a gentle, rounded curry rather than a hot one. The spice is warming rather than fiery, with sweetness from softened onion, carrot and often a little apple or honey, and a savoury base from stock and soy sauce. The texture is smooth and glossy, thick enough to coat the back of a spoon. Most people find it closer to a chip shop curry sauce than to an Indian curry.

What is in it

Japanese curry is built on a roux: flour cooked in fat with curry powder, then loosened with stock. A homemade version usually includes:

  • Onion, carrot, garlic and ginger, softened until sweet.
  • Mild curry powder, often with a pinch of garam masala.
  • Plain flour to thicken, cooked out in the oil first.
  • Chicken or vegetable stock.
  • A little soy sauce, honey or sugar, and sometimes grated apple, to round it off.

Ready made block mixes such as S&B Golden Curry and House Vermont Curry are this roux, set into a bar. You melt a few squares into simmering stock and vegetables, and the sauce thickens in a few minutes.

How to make a quick katsu curry sauce

  1. Soften 1 chopped onion and 1 grated carrot in 1 tbsp oil for 8 to 10 minutes.
  2. Add 2 crushed garlic cloves and a thumb of grated ginger, and cook for 1 minute.
  3. Stir in 1 tbsp mild curry powder and 1 tbsp plain flour, and cook for 1 minute more.
  4. Pour in 400ml stock a little at a time, stirring, then add 1 tsp soy sauce and 1 tsp honey.
  5. Simmer for 10 minutes, then blend smooth if you like and season to taste.

For the full method, with breaded chicken, see our chicken katsu curry recipe or the sauce on its own in our katsu curry sauce recipe.

What to serve it with

The classic is crisp chicken katsu sliced over rice with the sauce poured alongside. It works just as well with breaded pork, fried tofu, aubergine or prawns, or simply spooned over rice with a fried egg. Pickled ginger or a little shredded cabbage on the side cuts through the richness.

Storing katsu curry sauce

Homemade sauce keeps for three to four days in a covered container in the fridge, and freezes well for up to three months. Bottled tonkatsu sauce keeps in the cupboard until opened, then goes in the fridge, like a bottle of brown sauce.

Frequently asked questions

Is katsu sauce spicy?

Katsu curry sauce is usually mild. Block mixes come in mild, medium hot and hot, so you can choose your level, but even the hot versions are gentle by curry standards.

Is katsu sauce vegan?

A homemade sauce with vegetable stock is. Some ready made jars and block mixes contain milk or meat extracts, so check the label.

Is katsu sauce gluten free?

Usually not. The roux is thickened with wheat flour, and most soy sauce contains wheat. Use cornflour and tamari for a gluten free version.

Can I use tonkatsu sauce for katsu curry?

No. Tonkatsu sauce is a sharp, fruity condiment, not a curry, so it will not give you the gravy a katsu curry needs.