Freezing salad dressing is not recommended as it can lead to changes in texture and flavor. Homemade dressings that contain ingredients like onion, may not freeze well and could become bitter or lose their freshness upon thawing. Additionally, the emulsion in the dressing might break during the freezing and thawing process, resulting in an undesirable separation. It's best to make only as much dressing as you need for immediate or short-term use to ensure the best taste and quality.