Sweet Potato Ginger Soup | IDDSI Level 4–5 Dessert Recipe

IDDSI Level 4–5 | 35 minutes | Easy

Sweet potato ginger soup (番薯薑糖水) is one of Hong Kong’s most humble and enduring tong sui (糖水) desserts — sold at street carts and dessert shops across the territory for well over a century. This adapted version cooks the sweet potato until fully tender, then blends it smooth with fresh ginger juice and yellow rock sugar to create a naturally sweet, warming purée that meets IDDSI Level 4. The natural sugars from the sweet potato reduce the need for added sweetener, making it a gentle, nutritious option for elderly residents.

Ingredients (4 servings)

Main:

• 400g yellow-fleshed sweet potato (黃心番薯), peeled and cut into 3cm pieces
• 20g fresh old ginger (老薑), peeled and finely grated
• 60g yellow rock sugar (片糖), or adjust to taste
• 800ml water

Optional:

• 2 pandan leaves (for fragrance)
• 2 tablespoons coconut cream (added at the end for richness and additional calories)

Method

1. Peel sweet potato and cut into 3cm chunks. Rinse under cold water.
2. Bring water to a boil in a medium saucepan, adding pandan leaves if using.
3. Add sweet potato chunks and cook over medium heat for 20 minutes until completely tender — test by inserting a chopstick; it should pass through with no resistance.
4. Remove pandan leaves. Transfer sweet potato and all cooking liquid to a blender.
5. Add grated ginger and blend on high for 60 seconds until completely smooth.
6. Return blended soup to the saucepan. Add rock sugar and stir over medium-low heat until fully dissolved.
7. Taste and adjust sweetness; add hot water to thin if needed to reach desired Level 4 flowing consistency.
8. Stir in coconut cream (optional) just before serving. Serve hot.

Texture Test

IDDSI Level 4 confirmation: When scooped with a spoon, the blended sweet potato soup flows slowly and cannot hold a shape — consistent with Level 4 pureed food.

Note: Sweet potato variety affects thickness. Yellow-fleshed sweet potato (甘薯) is higher in starch and blends thicker. If the result is too thick to flow slowly (may reach Level 5), thin with additional hot water until the desired Level 4 consistency is achieved.

Safety Notes

⚠️ Cook thoroughly — undercooked sweet potato will leave fibrous particles after blending, resulting in an uneven texture that may not meet Level 4. Ensure the sweet potato is completely tender before blending.

⚠️ Blood sugar — sweet potato is naturally high in carbohydrates and the dish contains added sugar. Residents managing diabetes should reduce or omit the rock sugar and rely on the natural sweetness of the potato.

⚠️ Coconut cream — high in saturated fat; omit for residents with cardiovascular conditions.

Sourcing in Hong Kong

• Yellow sweet potato (黃心番薯): Available at all wet market vegetable stalls; quality is best in autumn and winter
• Yellow rock sugar (片糖): All supermarkets — Cantonese flat sugar slabs give the most authentic flavour
• Old ginger (老薑): All wet markets and supermarket produce sections
• Pandan leaves (斑蘭葉): Fresh at wet market vegetable stalls or packaged at supermarkets

Nutrition

Approximately 160 kcal per serving (without coconut cream), 38g carbohydrates, 3g dietary fibre. Sweet potato is rich in beta-carotene, Vitamin C and potassium; ginger contains gingerols that may aid digestion and circulation; yellow rock sugar contains trace minerals. The dish is low in fat and protein, so it is best served as a dessert supplement to a protein-containing main meal.

Cultural Note

Sweet potato ginger soup is one of the most working-class and genuinely beloved desserts in Hong Kong food history. For generations, it was the most accessible tong sui in the territory — sweet potato grew abundantly, ginger was warming and cheap, and yellow sugar added just enough sweetness to make the combination feel luxurious. Street vendors would sell it from bubbling cauldrons on winter evenings, and the aroma of ginger and sweet potato is still instantly evocative for many older Hong Kongers. Served in Level 4 pureed form, this recipe preserves the warmth and simplicity of the original while extending access to residents who need texture-modified food.