Monday, December 28, 2020
The Culinary Cook Cooking Basics Thickening Agents For Sauces & Soups

Thickening Agents For Sauces & Soups


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Thickening Agent Types

Thickening agents are used in all types of cooking methods and there are a lot of different kinds of thickening agents you need to be aware of. Choosing the right type of food thickener can make or break your dish and knowing the differences is useful in your journey in becoming a great cook. Before I was trained in the culinary industry as a professional cook, I had no idea how to thicken a sauce or soup and many times I ended up doing inadvertently. This guide was developed to introduce you to the various types of food thickener and how you can apply them in your every day cooking.

Thickening Agent Types

  • Roux
  • Cornstarch Slurry
  • Whitewash
  • Liaison
  • Arrow Root
  • Beurre Manie


Choosing the right type of thickening agent can make or break your dish and knowing the differences is useful in your journey in becoming a great cook.

How Thickening Agents Work

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Almost all types of thickening agent, with the exception of reduction, use starch as its main thickening agent. There are many sources and combinations for proper starch thickening. Starch becomes gelatinous when it is cooked, producing a thickening property that blends well into many foods. Cooked properly, a gelatinized starch has a very neutral flavor and can be used in moderation with most foods to produce a thick product. Too much gelatinized starch causes food to take on the bland flavor and dilutes much of the flavoring you initially used.

Starches that are not thoroughly cooked properly have a very “starchy” flavor that can come through prominently in your food. This is why it is important to continually taste your food to ensure the starch has been cooked.


flour thickener
Flour, the most basic food thickener

A whitewash thickening agent is a mixture of flour and water that has been combined prior. The mixed liquid is then added to a soup/sauce. While it works well, the combination of water and flour produce a very flavorless thickener. A whitewash also has a risk of separation with what it was thickening. A whitewash is best used when you need to thicken a dish that is to be served immediately and can withstand a hit in the flavor department. Overall, a whitewash is a cheap, fast solution for thickening that can be used in a pinch.

Cornstarch Slurry

A Thickened Sauce
A Thickened Brown Sauce

A slurry thickening agent is the same as a whitewash, except cornstarch is used instead of flour. Cornstarch is mixed with water and then added to the soup/sauce. Never add dry cornstarch to a product that needs thickening, as you will produce lumps that will be next to impossible to use. The proper technique is to add a cold slurry to a hot liquid while stirring constantly. Starches begin to gelatinize around 60C (140F), so don’t be alarmed when you don’t notice immediate thickening action. A common mistake is thinking there isn’t enough slurry and adding more, resulting in an incredibly thick liquid once the starches do gelatinize.

A cornstarch slurry is preferable over a whitewash. The thickening power is more prominent which results in less flavor loss. Cornstarch slurries tend to separate from fats and other liquids if kept for long periods.


thickening agent
A blond roux ready for liquid!

A roux is a mixture of fat and flour. It is the recommended method for thickening sauces and soups as it does not separate. Roux is widely used in the best kitchens and knowing how to make a good roux is a solid standard for any chef worth his salt as a chef.

A roux is comprised of, by weight, 50% flour, and 50% fat. It is always suggested you use butter as your fat, but you may also use canola/olive oil/other oils. Just remember, the oil you use will have an adverse impact on your flavor.

There are 3 stages of a roux.

  • White Roux
  • Blond Roux
  • Brown Roux

A white roux retains its initial color and is only cooked slightly to remove any starchiness from the roux. A blonde roux is caramelized slightly to give it a darker blonde color. A brown roux is cooked until almost burnt; highly caramelized, it also has a nice nutty flavor to it.

The 3 stages of roux

It is important that the temperature of the roux and the liquid that you add are in direct contrast, otherwise, you may experience clumping. That is, if you have a hot roux, add only room temperature water. If you have a hot liquid, only add the cooled roux.

Deciding which roux to use depends on what you’re using it for. White roux is used for white sauces and cream soups. Blond roux’s for ivory colored sauces such as a veloute, or when a richer flavor is desired. A brown roux is used in brown sauces and dishes were a dark color is desired.

It is important to remember that cooking a starch without liquid breaks down the starch granules and prevents proper gelatinization from occurring.


It is important that the temperature of the roux and the liquid that you add are in direct contrast, otherwise you may WILL experience clumping.


Arrowroot Thickening Agent
Arrowroot Thickening Agent

An arrowroot thickening agent is derived from several tropical plants and is similar in texture, appearance and thickening power to cornstarch and is used in exactly the same way. Arrowroot is more expensive, but produces a clearer finished product and doesn’t break down as quickly as cornstarch would.

Beurre Manie

Beurre Manie thickening agent is a combination of equal parts flour and softened butter. It is then kneaded together and formed into tiny balls to be dropped into sauces for flavor and thickening power. It is mainly used for quick thickening or thickening at the end of the cooking process. The butter adds shine and flavor as it melts.


Unlike most thickeners, a liaison thickening agent doesn’t thicken by gelatinization. A liaison is a mixture of egg yolks and heavy cream that adds richness and smoothness with a minimal thickening. It is important to ensure you prevent the egg yolks from coagulating when they are added to a hot liquid. The ratio is generally 3 yolks to 200ml (7 fl. oz) cream.


thickening agent sauceThe reduction is the process of removing the water that is present in many ingredients leaving a more pronounced and concentrated flavor. A good example is a red wine reduction, in which wine is reduced with a simmer until by half or au sec. This produces a much more concentrated flavor that can be added to sauces to make a delicious and high-end sauce.

The reduction is a useful method of thickening if it makes sense to do so. You don’t want to reduce a soup to thicken it, because not only will you be waiting many hours but you’ll lose a lot of your yield. You must decide when it’s appropriate to reduce and when common sense dictates the use of a thickening agent.

Now that you understand the variations of thickening agents, you can confidently make an executive decision the next time you are wondering how to thicken your soup or sauce.

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  1. OMG i have an assessment on this exact topic……….. I cant believe i actually found the ultimate culinary site with all the info. #so so grateful!!


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The Culinary Cook

Professional Chef & Blogger

With 15 years of experience working in restaurants, resorts, and a fully Red Seal Certified chef, The Culinary Cook shares tips, tricks, and recipes for everyone to enjoy.

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