The classic method of stewing old duck soup with raw rehmannia is to stew raw rehmannia and old duck together to extract the medicinal ingredients of raw rehmannia and give the duck soup a nourishing effect. Generally speaking, pickled radish is not added directly to this traditional recipe.

If you want to try adding sour radish, you can consider the following factors:

Taste combination: Sour radish has a sweet and sour taste, which may conflict with the delicious taste of the old duck. You need to judge whether it is suitable for matching based on personal preference.

Medicinal properties: Rehmannia glutinosa is a traditional Chinese medicinal material that has the effects of clearing away heat and cooling blood, nourishing yin and moisturizing dryness. The sour taste of pickled radish may affect the medicinal efficacy of raw rehmannia, so it is recommended to avoid adding other ingredients when using raw rehmannia to make medicinal meals.

In short, if you want to maintain the classic effect of raw duck soup, it is best not to add pickled radish. If you want to try new flavor combinations, experiment on a small scale and adjust the ingredients to your personal taste.