Final answer:
The standard ratio of roux to liquid for a medium consistency is 1:3.
Step-by-step explanation:
The standard ratio of roux to liquid varies depending on the desired consistency. For a medium consistency, the ratio is typically 1 part roux to 3 parts liquid. This means that for every 1 unit of roux, you would use 3 units of liquid.
For example, if you were using white, blond, or brown roux to make a sauce, you would use 1 cup of roux to 3 cups of liquid to achieve a medium thickness.