3-5 minutes. Asparagus is a crunchy texture of vegetables, commonly used in cooking a variety of dishes, such as asparagus fried shredded pork, asparagus roasted duck and so on. Asparagus blanching time is short, oxalic acid removal is not sufficient, asparagus will taste more astringent, blanching time should not be too long, generally 3-5 minutes can be, too long will lead to asparagus soft, affecting the taste.