Liaison in catering terms is a binding agent.
Although a binding agent in cooking can be anything from bread crumbs to flour if the term “liaison” is used it will only refer to a mixture of cream and egg yolks as a thickening agent for soups or sauces

.Liaison is commonly used in classic French cuisine and can be found in dishes like creamy sauces, velvety soups, and custards. It adds a luscious and velvety finish to the final preparation, enhancing both the flavor and texture of the dish. However, it’s important to be careful with the cooking process to avoid overcooking the liaison, as excessive heat can cause the egg yolks to curdle and ruin the desired texture of the dish.


How do Chefs Produce a Liaison

Chefs produce a liaison by carefully combining egg yolks and cream (or sometimes just egg yolks) with the hot liquid they want to thicken. Here’s a step-by-step guide on how they achieve this technique:

Gather the ingredients: You will need egg yolks and cream (or just egg yolks) as the base for the liaison. The ratio of egg yolks to liquid depends on the desired thickness and richness of the final dish.

Prepare the hot liquid: Heat the liquid (such as broth, sauce, or soup) in a separate pot until it’s hot but not boiling. It’s essential to bring it to a temperature just below boiling to avoid curdling the egg yolks.

Create the liaison mixture: In a separate bowl, whisk the egg yolks (and cream, if using) together until well combined. The cream, when used, adds extra richness and a smoother texture to the liaison.

Temper the egg yolks: To prevent the egg yolks from curdling when added to the hot liquid, it’s crucial to temper them first. Gradually add a small amount of the hot liquid to the egg yolk mixture while constantly whisking. This process gradually increases the temperature of the egg yolks without cooking them too quickly.

Incorporate the liaison into the hot liquid: Once the egg yolks are tempered, slowly pour the egg yolk mixture back into the hot liquid while stirring continuously. This step should be done off the heat to avoid curdling.

Cook over low heat: Return the pot to low heat and continue stirring gently as the liaison thickens the liquid. Be careful not to raise the heat too much, as this can cause the eggs to curdle and ruin the texture of the dish.

Monitor the consistency: Keep a close eye on the liaison as it cooks to achieve the desired thickness. The mixture should coat the back of a spoon without being overly thick or lumpy.

Serve or incorporate into the dish: Once the liaison has thickened the liquid to the desired consistency, it is ready to use. It can be served immediately or incorporated into sauces, soups, or other dishes to provide a creamy and velvety texture.

By following these steps, chefs can successfully produce a liaison to enhance the texture and richness of their culinary creations.