Poolish Steamed Bun （Mantou / 波兰种开花馒头）

There's something incredibly satisfying about lifting the steamer lid to reveal perfectly fluffy steamed buns with beautiful natural cracks on top. Those "blooming" buns aren't just attractive. They're often a sign of a well-fermented dough with a light, airy texture.

This time, I experimented with using a poolish starter to make my mantou, and the results were well worth the extra planning. The buns turned out exceptionally soft, with a finer crumb, a subtle sweetness from natural fermentation, and a richer wheat aroma that you simply don't get from mixing everything together in one go. 

What Is a Poolish?

A poolish is a simple pre-ferment made with equal parts of flour and water, plus a tiny amount of yeast. It is left to ferment for several hours, or overnight, before being mixed into the final dough.

Although poolish is commonly used in artisan bread baking, it also works wonderfully for Chinese steamed buns. The slow fermentation develops flavor naturally while improving the dough's structure.

Why Use a Poolish for Mantou?

Using a poolish offers several advantages:

1) Produces a finer, even crumb.

2) Creates softer buns that stay fresh longer.

3) Develops a richer wheat flavor with a slightly natural sweetness.

4) Improves dough strength while keeping it light and fluffy.

5) Encourages better oven spring or in this case, better "steam spring" for beautifully blooming buns.

The extra fermentation time may seem like an additional step, but most of it is hands-off, letting time do the work.

The Secret to Blooming Steamed Buns

Those beautiful cracks don't happen by accident. They are the result of several factors working together:

1) A well-fermented dough with enough strength.

2) Proper shaping that creates surface tension.

3) A final proof that isn't excessive.

4) Strong steam when the buns begin cooking.

As the dough rapidly expands in the hot steam, the surface naturally splits, creating the signature blooming appearance. Every bun blooms differently, making each one unique.

If you're looking for steamed buns with a softer bite, finer texture, and deeper flavor, a poolish starter is a simple technique that makes a noticeable difference. While it requires a little advance planning, the actual effort is minimal, and the reward is bakery-quality mantou made right at home.

Whether you enjoy your mantou plain, with sweet fillings, or alongside savory dishes, using a poolish starter is a technique worth adding to your baking repertoire.

Once you try it, you may never go back to making steamed buns the traditional straight-dough way.

Full written steps,  tips, and exact measurements are below. Keep scrolling!

INGREDIENTS

Poolish Starter

1/4tsp yeast

75g water

75g flour

Purple Sweet Potato Dough

200g flour

60g sugar

1 tsp yeast

½ tbsp baking powder

100g Purple Sweet Potato puree

½ potion Poolish Starter

50ml water

1 tbsp cooking oil

Pumpkin Dough

200g flour

60g sugar

1 tsp yeast

½ tbsp baking powder

100g Pumpkin puree

½ potion Poolish Starter

1 tbsp water (if needed )

1 tbsp cooking oil

METHOD

1. To make the poolish starter

Combine the flour, water, and yeast in a bowl. Mix it well. Cover with plastic wrap. Let it ferment in the fridge for 12 to 24 hours.

2. To make the purple sweet potato dough

Combine the flour, sugar, baking powder, and yeast in a mixing bowl. Add the purple sweet potato purée, half of the poolish and water. Mix until a rough dough forms. Add in oil, continue kneading until smooth and elastic. If the dough feels too dry, add a little more water, one tablespoon at a time, until it becomes soft and slightly tacky. Cover and let it rest for 5 minutes.

3. To make the pumpkin dough

Combine the flour, sugar, baking powder, and yeast in a mixing bowl. Add the pumpkin purée, the remaining poolish, and just enough water to bring the dough together. As the pumpkin dough tends to be soft and slightly tacky, add the water gradually, one tablespoon at a time, knead until it forms a rough dough. Add in oil, continue kneading until smooth and elastic.  Cover and let it rest for 5 minutes.

4. Divide each dough into 10 equal portions and roll them into smooth balls. Flatten one piece of the purple sweet potato dough, place a pumpkin dough ball in the center, and seal it tightly. (Alternatively, wrap the purple dough with the pumpkin dough for a different color effect.)

5. Place the buns seam-side down and use a sharp knife or razor blade to make cross-shaped incision on the top of each bun.

6. Cover and proof for about 30 minutes, or until the dough springs back slowly when lightly pressed with your fingertips. The indentation should partially bounce back but remain slightly visible.

7. Once the water comes to a full boil, place the buns in the steamer and steam over high heat for 15 minutes. When done, turn off the heat and let the buns rest in the steamer for 5 minutes before opening the lid to prevent them from shrinking or wrinkling. 

Tip of success

1. Knead Until Smooth

Well-developed gluten is essential for fine-textured mantou. The dough should feel smooth, elastic, and slightly tacky but not sticky. A properly kneaded dough will produce a more uniform crumb and better rise.

2. Add water to dough incrementally

The common practice is to add a little water if the dough feels too dry. In fact, holding back a little of the water from the recipe, and adding it incrementally, going by feel rather than measurement, is the preferred way to get a perfect dough.

3. Don't Over-Proof

For blooming steamed buns, slightly under-proofed dough often works better than over-proofed dough. If the dough is over-proofed, the buns may rise well but remain smooth instead of developing the desirable cracks on top.

4. Start with Strong Steam

Make sure the water is already boiling before placing the buns in the steamer. The sudden burst of heat helps the dough expand rapidly, creating the characteristic bloom.

5. Leave Enough Space Between Buns

Steamed buns expand significantly during cooking. Give them enough room to grow without touching one another.

Resist the temptation to peek. Opening the lid during steaming can cause a drop in temperature and affect the final texture and volume.

6. Let the Buns Rest Before Opening the Lid

Once steaming is complete, switch off the heat and let the buns rest in the steamer for 3–5 minutes. This helps prevent the surface from wrinkling due to a sudden temperature change.