Also Known as Water Hydration or Water Absorption Capacity (WAC)
What is Water Absorption?
Water absorption is the amount of water taken up by flour to achieve the desired consistency or optimal end result. It is usually defined based on flour weight. For example, 60% water absorption means 60 lbs of water is required for every 100 lbs of flour.
Water absorption influences the following parameters of baking and bread:
- Loaf volume: Higher water absorption leads to greater amounts of water vapor being driven off during the oven spring phase, contributing to the higher loaf volume.1
- Fracture stress of bread crumb: High water absorption decreases the fracture stress of bread crumb.1
- Bread yield: High water absorption increases bread yield.2
- Final products attributes3
- Shelf life3
How to measure water absorption?
A Farinograph and Mixograph can give an approximate number for water absorption.
The farinograph uses a controlled sample of flour at a certain weight. It is added into the farinograph mixing bowl while a buret deposits a known amount of water into the flour sample. Once dough is formed, the farinograph records a curve onto graph paper. As water is continually added, absorption causes the recorded line on the graph paper to slant downward while a decrease in the addition of water causes the graph line to move upward. By observing the collected data, the farinograph supplies water absorption capacity as well as dough strength and mixing requirements for dough development.
The other water absorption calculation method is using the mixograph, which is performed a few times based on a calculation.
Water absorption levels will vary from 50-54% in a cookie formula, 60-62% in a standard white bread formula4, and 80-90% in an artisan type Ciabatta formula.When developing with sprouted flour, the increase in enzymatic activity in the flour will increase water absorption and maillard reaction.6
Influencing factors of flour water absorption:
- Pentosans: Absorbs the most water within the flour.
- Damaged Starch: Absorbs the second-most water due to fissures and cracks on the outer layer of the starch granule.
- Protein: Absorbs the third-most amount of water; primarily insoluble in water.
- Intact or Native Starch: Does not maintain great water retention capabilities.
- Vital Wheat Gluten: When added to the formula, it will increase the water absorption and impart greater stability to the dough.5
- Zghal, M. C., M. G. Scanlon, and H. D. Sapirstein. “Effects of Flour Strength, Baking Absorption, and Processing Conditions on the Structure and Mechanical Properties of Bread Crumb.” Cereal Chemistry Journal 78.1 (2001): 1-7.
- Puhr, D. H., and B. L. D’Appolonia. “Effect of Baking Absorption on Bread Yield, Crumb Moisture, and Crumb Water Activity.” Cereal Chem. 69.5 (1992): 582-86.
- Pyler, E. J. “Physical and Chemical Test Methods.” Baking Science & Technology. Merriam, Kan.: Sosland Pub., 1988. 851-71.
- Cauvain, Stanley P., and Linda S. Young. Technology of Breadmaking. New York: Springer, 2007. P360.
- Indrani, Dasappa, and Gandham V. Rao, comps. “Functions of Ingredients in the Baking of Sweet Goods.” Food Engineering Aspects of Baking Sweet Goods. Boca Raton: CRC, 2008. 31-48.
- Carson, Lin. “Just How Hot Are Sprouted Grains? | Blog.” Bakerpedia. 27 Feb. 2017. www.bakerpedia.com/just-hot-sprouted-grains/. Accessed 02 May 2017.