Tangzhong (from the Chinese 湯種, tāngzhǒng) is a breadmaking method derived from the Japanese breadmaking method yukone or yudane. It’s recently gained popularity largely thanks to the Chinese cookbook 65°C Tangzhong Bread by Yvonne Chen. For the tangzhong method, a small portion of the flour and water are cooked together to 65°C (149°F), then added to the rest of the bread ingredients. Tangzhong is known to keep breads softer and moister for longer due to the gelatinized starch in the cooked flour. To taste the effects of tangzhong for ourselves, we made two sets of bread rolls with the same ingredients. Half the rolls were made with tangzhong, and half the rolls were made without.
Experiment Overview
Goal: To taste differences in texture between rolls baked with and without tangzhong
Recipe: Adapted from Hokkaido Milk Bread by Cynthia Chen McTernan and Japanese Milk Bread Rolls by King Arthur Baking
Method: Prepare two batches of bread dough, one with tangzhong and one without. Bake, cool, and compare.
Results: Between the two types of bread, we noticed differences in
– Water absorption
– Dough toughness
– Roll crumb
– Roll texture
Conclusions: The tangzhong absorbs a lot of water to make a drier dough that’s easier to work with. The baked bread retains more moisture for a softer texture, and it stays fresher for longer.
Test Method
Ingredients and Equipment
- 6 Tbsp water
- 2 Tbsp + 318g + 16g Gold Medal bread flour, divided
- 61g Friendly Farms whole milk at 110°F
- 1 1/2 tsp Baker’s Corner active dry yeast
- 1/2 tsp salt
- 50g Baker’s Corner granulated sugar
- 63g Countryside Creamery heavy whipping cream
- 1 large Goldhen egg
- 2 Tbsp Countryside Creamery unsalted butter, softened and divided
- 1 Goldhen egg white
- 9-inch cake pan
Making the rolls
- Whisk together the water and 2 Tbsp bread flour (104g total). Divide in half (52g each). Set one portion aside for the no-tangzhong rolls. Cook the other portion over low heat, stirring constantly, until the whisk leaves lines in the mixture. Remove from heat and cool. This is the tangzhong.
- Combine the yeast and the warm milk. Let sit 5–10 minutes.
- In the meantime, whisk together the remaining 318g bread flour, salt, and sugar (374g total). Divide this mixture in two (187g).
- Add the cream and egg to the yeast mixture (170g total). Mix well and divide in two (85g each). To one portion, add the tangzhong. To the other, add the uncooked water and flour mixture. Combine both sets of wet ingredients well.
- Make a well in each bowl of dry ingredients and add the wet ingredients. Knead both doughs, adding 8g bread flour to each dough to prevent sticking, until smooth. Knead 1 Tbsp butter into each dough in two additions. Continue kneading until the dough is smooth and elastic and passes the windowpane test. Form each dough into a ball, place it in a greased bowl, cover, and refrigerate overnight.
- The next day, punch down the doughs and divide each into 4 portions (78g each). Form each portion into a ball and place them in a greased cake pan. Cover and rise 1 hour. Preheat the oven to 350°F when the rolls are almost ready to bake.
- Brush egg white onto the rolls. Bake for 25–30 minutes until golden brown. Remove from oven, cool, and taste.
Results
To better understand some of these results, I suggest reading through the last few posts about starch, especially the introduction and the one about flour. At the end of the flour post, I discuss the effects of cooking flour before baking it.
Water absorption
The tangzhong changed dramatically as soon as we cooked it. The soupy liquid thickened into a paste. As we described in the introduction, heat gives water molecules the energy they need to penetrate starch granules in the flour. The granules swell and leak starch molecules into the water, and the resulting network of swollen granules and large starch molecules traps water and thickens the liquid. Water at room temperature cannot do this. In the uncooked mixture, the proteins and starch in the flour absorb a little water, but the consistency remains thin.
This difference carried into the bread doughs. Because the flour absorbed more water, the tangzhong dough was consistently drier, which made it easier to knead and shape. The difference in water absorption was also reflected in the shape of the rolls after the second rise. Although all the rolls started off as balls, the wetter no-tangzhong rolls spread more in the pan while the tangzhong rolls held their round shape, so the baked tangzhong rolls are more circular than the no-tangzhong ones.
Dough toughness
As I kneaded, the no-tangzhong dough started to feel tougher than the tangzhong dough despite its extra water. This most likely came down to differences in the developing gluten structure. Typically, the water in a bread dough hydrates both starch and gluten proteins in the flour, and we link the gluten into a large net as we knead. This net provides structure, but since it’s elastic, it also feels tight.
When we cook the tangzhong, the flour absorbs the water. This water is now unavailable to hydrate proteins in the remainder of the flour. The heat also denatures the gluten-forming proteins in the tangzhong, and without their shape, the proteins cannot form gluten nets. More importantly, the tangzhong now contains swollen, gelatinized starch granules. When added to the rest of the dough, these granules may interfere with gluten development. In a highly magnified image of baked bread with and without tangzhong, Naito and colleagues (2005) found that the gluten nets in tangzhong bread were thicker and more open than the gluten nets in no-tangzhong bread, suggesting that the gelatinized starch granules and denatured protein from the tangzhong may have restricted gluten formation.
Roll crumb
As you may recall from our discussions about gluten and leavening, gluten traps the gases that raise the bread. The expanding gases push against the dough, and those bubbles form the final crumb of the bread. Because the tangzhong dough has coarser gluten, it’s worse at holding gases. We didn’t notice any differences in the rise times or final loaf volumes of the two types of rolls, but other scientists have measured the lower efficiency of tangzhong doughs in trapping gas (Yamauchi et al., 2014).
Given the differences in the proportions of gelatinized starch and gluten in the two doughs, we might also expect differences in crumb. It’s hard to be certain from the photos of our rolls, but Yamauchi and colleagues also showed that the crumb does change with the addition of gelatinized starch (2014). Tangzhong breads have a greater proportion of larger, more circular holes, while no-tangzhong breads have more smaller, long holes.
Roll texture
How did the starch translate into the texture of the rolls? Both were rich and fluffy. It was difficult to tell them apart, but the tangzhong rolls were marginally softer because the gelatinized starch in the tangzhong kept water trapped as the rolls baked. This difference became more pronounced over time. If you remember from previous posts, one of the processes that contributes to staling is starch retrogradation, where gelatinized starch reorganizes into hard crystals. The tangzhong rolls remained softer for longer because this recrystallization was slowed.
As we discussed, flour contains enzymes called amylases that break starch down into smaller sugars, but whole, intact granules are difficult for them to access. Like starch granules cracked open in the milling process, gelatinized starch, with its swollen granules and leaking starch molecules, is more accessible to amylases. In the tangzhong dough, the amylases from the uncooked flour break down the pregelatinized starch in the tangzhong, creating small sugar molecules. Unlike starch, these small fragments cannot retrograde into the hard crystals that contribute to staling. In fact, they may even slow the process by getting in the way of the large starch molecules as they try to realign.
In the no-tangzhong dough, there is no pregelatinized starch for the amylases to break down, so they can only work on the damaged starch granules. As a result, there are fewer small sugar molecules present in the baked rolls to prevent the starch molecules from recrystallizing, and the bread stales faster.
Because they contain more sugars, tangzhong breads may be sweeter than their no-tangzhong counterparts. However, we could not taste a difference in sweetness with these rolls.
Conclusions
By heating a mixture of water and flour and gelatinizing the flour’s starch, the tangzhong method helps us make high-hydration doughs that retain more moisture. The result is a softer, fluffier bread. And because the gelatinized starch is prone to breakdown by amylases, baked tangzhong breads contain sugars that delay staling. It’s a technique that can enhance the texture and shelf life of any soft bread. (King Arthur has a handy guide on how to convert recipes for tangzhong.) But pregelatinized starches aren’t handy for just bread. In the next post, we’ll explore how we can use a similar technique to create fluffier chiffon cakes.
References
Corriher, S. O. Bakewise; Scribner: New York, 2008.
Corriher, S. O. Cookwise, 1st ed.; William Morrow and Company, Inc.: New York, 1997.
Durán, E.; León, A.; Barber, B.; Benedito de Barber, C. Effect of low molecular weight dextrins on gelatinization and retrogradation of starch. European Food Research and Technology, 212, 203–207, 2001.
Figoni, P. How Baking Works, 3rd ed.; John Wiley & Sons, Inc.: Hoboken, 2011.
Hamel, P. Introduction to tangzhong. King Arthur Baking, 2018.
Naito, S.; Fukami, S.; Mizokami, Y.; Hirose, R.; Kawashima, K.; Akano, H.; Ishida, N.; Koizumi, M.; Kano, H. The Effect of Gelatinized Starch on Baking Bread. Food Science and Technology Research, 11(2), 194–201, 2005.
Yamauchi, H.; Yamada, D.; Murayama, D.; Santiago, D. M.; Orikasa, Y.; Koaze, H.; Nakaura, Y.; Inouchi, N.; Noda, T. The Staling and Texture of Bread Made Using the Yudane Dough Method. Food Sceince and Technology Research, 20(5), 1071–1078, 2014.