Your sauce tastes great but is far too runny? You don’t always need flour or a classic roux to get the consistency you want. There are plenty of ways to thicken sauces – from starch and puréed vegetables to simply reducing them.

Which method works best depends on the sauce you are making and the result you want. Some ingredients create a creamy texture, others barely change the flavour. Others again are particularly good for clear or dark sauces.

In this article, you’ll find out which alternatives there are, how to use them properly and what to watch out for.

1. Starch – the easy classic

Starch is one of the easiest ways to thicken sauces without flour. Cornflour and potato starch are the most commonly used.

How it works:

1. Stir the starch into a little cold water until there are no lumps left.
2. Add the mixture to the hot sauce, stirring constantly.
3. Heat the sauce, stirring, until it thickens.

As a guide for 250 ml of sauce:

• 1 tsp starch for light thickening
• 2 tsp starch for a noticeably thicker sauce

How much you need depends on the starch you use and the consistency you want.

Advantages:

• Neutral flavour
• Quick and easy
• Suitable for many light and dark sauces
• Naturally gluten-free if it is pure corn or potato starch

Important: Never add starch to the hot sauce as a dry powder, or lumps can form. Once it has thickened, don’t boil potato starch for longer than necessary.

2. Puréed vegetables – naturally creamy

Another option is to use vegetables as a thickener. Cooked carrots, pumpkin, courgette, cauliflower or potatoes work particularly well.

The vegetables give the sauce a velvety consistency and can complement its flavour at the same time.

How it works:

1. Cook the vegetables until soft.
2. Purée them as finely as possible with a little sauce or cooking liquid.
3. Stir the vegetable purée into the rest of the sauce.
4. Add a little liquid if needed until the consistency is right.

As a guide: Start with about 50–100 g of cooked vegetables per 250 ml of sauce and adjust the amount as needed.

Particularly good for:

• Creamy vegetable sauces
• Pasta sauces
• Soups
• Light, vegetable-based sauces

Tip: Cauliflower has a fairly mild flavour, while pumpkin and carrots add a little sweetness. Potatoes thicken strongly, but can turn gluey if blended too hard.

3. Reducing the sauce – no extra ingredients needed

To reduce a sauce, you simmer it uncovered. Water evaporates, concentrating both flavour and consistency.

This method is particularly good for sauces that are already full of flavour and don’t need any additional thickener.

How it works:

1. Simmer the sauce uncovered over a low to medium heat.
2. Stir occasionally so nothing catches.
3. Let it reduce until it reaches the consistency you want.

Advantages:

• No additional ingredients needed
• More intense flavour
• Particularly good for gravies, stocks and tomato sauces

Disadvantages:

• Takes a little more time
• There is less sauce
• Salt and spices become more concentrated

Tip: Only salt a sauce you want to reduce a lot towards the end. That way, it won’t end up too salty.

Not every liquid thickens automatically when reduced. Very watery liquids without enough dissolved or binding components can stay fairly thin even after reducing for a long time.

4. Cream cheese, sour cream and yoghurt – for creamy sauces

Dairy products can give sauces a creamier consistency. They work best in light sauces and dishes where a slightly tangy or milky note is welcome.

Suitable ingredients:

• Cream cheese
• Sour cream
• Crème fraîche
• Greek yoghurt
• Skyr

How it works:

1. If necessary, reduce the amount of liquid in the sauce first.
2. Stir a few spoonfuls of the dairy product until smooth.
3. Mix it with a little warm sauce.
4. Return the mixture to the pan and warm it gently.

As a guide: Start with 1–2 tbsp per 250 ml of sauce.

Important: Yoghurt, skyr and sour cream can split if the heat is too high, especially in acidic sauces. So add them towards the end if you can and avoid boiling hard.

These ingredients make a sauce creamier, but they don’t always replace a proper thickener. Low-fat products in particular can even thin a sauce at first.

5. Potatoes or potato flakes – easy and filling

Cooked potatoes contain starch, which makes them good for thickening soups and savoury sauces.

Unseasoned instant mash flakes can also be used.

How it works:

• With cooked potatoes: Mash a small, soft-cooked potato, or purée it finely with a little sauce, and stir it in.
• With potato flakes: Stir in a small amount first, let it swell briefly and check the consistency.

As a guide: With potato flakes, start with about 1 tsp per 250 ml of sauce.

Advantages:

• Thickens quickly
• Particularly good for hearty sauces and soups
• Often already in the cupboard

Disadvantage: If you use too much, the sauce can end up more like a thin purée.

Tip: If possible, use plain potato flakes without added spices or milk ingredients if you want to change the flavour of the sauce as little as possible.

6. Nut butter – creamy and flavourful

Nut butter can also change the consistency of a sauce. Cashew butter and almond butter are especially good for creamy dishes.

Nut butter works differently from starch, though: its fat and solids mainly create a creamy emulsion and more body.

How it works:

1. Stir 1 tsp of nut butter into a little warm sauce.
2. Return the mixture to the pan.
3. Stir thoroughly until it is fully combined.

As a guide: About 1–2 tsp per 250 ml of sauce, depending on how creamy you want it.

Particularly good for:

• Vegetable and curry sauces
• Creamy pasta sauces
• Plant-based sauces

Important: Nut butter changes the flavour and increases the fat content of the sauce. This method is not suitable if you have a nut allergy.

7. Coconut milk or coconut cream – for certain sauces

Coconut milk and especially coconut cream are good for sauces where the coconut flavour suits the dish.

Thanks to their fat content, they can make a sauce richer and creamier. Thin coconut milk doesn’t automatically thicken, though.

How it works:

1. Add a little coconut cream or full-fat coconut milk to the sauce.
2. Stir everything thoroughly.
3. Let the sauce reduce briefly if needed.

Particularly good for:

• Curries
• Asian-inspired sauces
• Vegetable dishes

Tip: If you want the thickest possible consistency, coconut cream usually works better than a low-fat coconut milk.

8. Psyllium husk – use sparingly

Psyllium husk absorbs a lot of liquid and forms a gel-like mass. This means it can also be used to thicken sauces.

However, it needs to be dosed very carefully, or the sauce can quickly become slimy or gel-like.

How it works:

1. Sprinkle a very small amount of finely ground psyllium husk into the sauce while stirring vigorously.
2. Leave it to swell for a few minutes.
3. Check the consistency before adding any more psyllium husk.

As a guide: Start with about ¼ tsp per 250 ml of sauce, or even less if the powder is very finely ground.

Advantages:

• A little goes a long way
• Even small amounts can bind liquid

Disadvantages:

• Unpleasantly gel-like if overdosed
• Not right for every sauce in terms of flavour and texture

For classic, smooth sauces, starch or reducing is often the better choice.

Which method suits which sauce?

Sauce	Recommended method
Light cream sauce	Starch, cream cheese
Dark gravy	Reducing, starch
Tomato sauce	Reducing, puréed vegetables
Vegetable sauce	Puréed vegetables, potatoes
Curry sauce	Coconut cream, nut butter, starch
Creamy pasta sauce	Cream cheese, vegetable purée
Clear sauce	Starch, careful reducing

The choice depends not only on the consistency but also on the flavour you want. For thickening with as little effect on flavour as possible, starch is usually the easiest solution.

Common mistakes when thickening sauces

The sauce goes lumpy

This often happens when starch is added straight to a hot liquid.

Solution: Always mix starch with cold liquid until smooth first, then add it while stirring.

The sauce is too thick

Too much thickener can make the consistency unpleasant.

Solution: Gradually add a little water, stock or another suitable liquid until the sauce is back to the consistency you want.

The sauce splits

Yoghurt and other tangy dairy products in particular can curdle over high heat.

Solution: Lower the heat, temper the dairy product with a little warm sauce and only stir it in towards the end.

The sauce turns slimy

This can happen, for example, with too much psyllium husk or with certain starches if they aren’t prepared properly.

Solution: Always use thickeners sparingly and follow the right method for each one.

Conclusion: what works best?

There is no single perfect alternative to flour. What matters is the sauce you are making and the result you want.

For quick, neutral-tasting thickening, starch is particularly handy. If you want to avoid extra ingredients and intensify the flavour, reducing is worthwhile. Puréed vegetables, in turn, are perfect for velvety, hearty sauces.

For creamy sauces, cream cheese, coconut cream or nut butter can be a good addition – even if they don’t always fully replace classic starch thickening.

It’s best to start with a small amount and adjust the consistency step by step. That way, you stay in control and avoid the sauce getting too thick.