The Art & Science of Bread-Making

Recent biochemistry graduate Tu Nguyen reflects on this year’s popular pandemic past-time and breaks down the science of bread-making!

During the first month of the pandemic, while everyone was stockpiling toilet paper, you might have noticed that supermarkets also kept running out of flour and yeast, causing a real headache for baking enthusiasts everywhere! For many cultures, bread is an integral component of our diet, and initial lockdowns provided ample opportunity to slow down and connect with one of mankind’s oldest traditions - baking bread. But other than time, have you ever wondered what goes into making a perfect loaf, and why? Let’s take a look at a classic white loaf. 

History of Bread

Approximately 12,000 years ago, the first bread, a simple combination of grains and water, was developed(1). 2,000 years later, the increased demand for higher-quality and more finely textured bread led to the invention of flour milling processes(2). Egyptians were the first nation to introduce the art of bread-making, which then became popular worldwide(1).

Understanding the Ingredients(2)

Homemade oatmeal banana bread - a great alternative for a gluten-free diet. Photo credit: Tu Nguyen.

Bread can play an important dietary role in many cultures(1). It is also a major source of energy and dietary fibre as well as crucial micronutrients, including B vitamins, folic acid, and fat-soluble vitamins and minerals, such as iron, calcium and magnesium(3). But to create that perfect loaf, we need to understand the key ingredients.

1. Flour

Flour is the foundation of bread. The baking properties of flour are dependent on the quality and quantity of its gluten, a type of protein that is activated only after flour is mixed with water. Gluten, a rubber-like network, has two main protein fractions: gliadins which determine the viscosity and extensibility of the dough, and glutenins which contribute to the dough’s strength and elasticity(4). Some of the best flour to make white bread is creamy white hard flour which has higher quality gluten, compared to soft flour (e.g. all-purpose flour).

2. Water

Water triggers the formation of the gluten network and the release of carbon dioxide gas from leavening agents, helping the dough expand. The amount of water used impacts the type of bread produced. 

• As a general rule (percentage of flour weight):

  • Finely textured, light bread: 50%

  • Heavier, more moist bread: 60% - 75%

3. Leavening Agents

Leavening agents are sources of gas that promote the expansion of the dough in the presence of moisture and heat. Some examples of leavening agents include:

• Yeast - a microscopic unicellular fungus, converts sugar into carbon dioxide gas, which can evenly lift and aerate the dough.

Types of yeast	Instant active dry yeast	Instant dry yeast
Direction	Dissolve with warm water	Add to dough
Weight	x0.25 water weight	x0.20 - 0.17 water weight
Temperature for optimal activation	42 - 44°C	32 - 38°C
Hydration time	15 minutes	N/A
Storing conditions	Below 7°C (with refrigeration) Closed container in cool, dry place (without refrigeration)	Room temperature

• Baking powder - a dependable and high-quality chemical leavener, reacts with at least one acidic ingredient to release carbon dioxide gas. Baking powder is activated by moisture and heat. Thus, it is better to evenly sift baking powder, then mix it with other dry ingredients before adding any wet ingredients. 

  • Amount of baking powder (percentage of flour weight): 5%

• Baking soda (sodium bicarbonate) - another chemical leavener, works with a sufficient acid (e.g., cocoa powder, buttermilk, honey, etc.) to produce twice the amount of carbon dioxide gas that baking powder can release alone. 

  • The amount of baking soda (percentage of flour weight): 0.7% - 1% 

  • Note: baking soda is basic (pH 8.0) and bread-making requires acidic conditions (pH 4.5 - 6.0). The addition of at least one acid is therefore necessary when using baking soda.

4. Fats

Fats and oils can contribute to the perfection of a loaf via four mechanisms. First, the tenderness of bread is developed as fats shorten the gluten strands in flour, making the bread softer and more digestible. Second, bread becomes creamier and lighter because when fats are beaten and added into the four mixture, air pockets form, extending and aerating the dough. Third, the plasticity of a dough is adopted from fats as they can “stretch” and stay workable within a range of temperatures. Fourth, the lubrication and moistening ability of fats help the gluten network expand more easily. 

• Amount of fat (percentage of flour weight): 3%

5. Sugar

Sugar is particularly important to fermented bread as it offers an immediate and more ready-to-use source of nourishment for yeast. As a result, more carbon dioxide gas is produced, allowing the dough to rise at a quicker and steadier rate. Furthermore, the browning effect of sugars, resulting from caramelization and Maillard reactions, gives a characteristic appearance and unique flavour to breads. Sugar also has some impact on the tenderness and moisture of the finished products.

• Amount of sugar (percentage of flour weight): 4%

6. Salts

The presence of salt prevents unwanted, wild-typed fermentation and bacterial growth. Salt decreases the rate of fermentation, lessening the destruction of sugar and assisting the browning effect. The expansion and strength of a dough is improved by salt as gluten-salt complexes can hold water and gas better and longer than gluten alone. Moreover, salt intensifies the flavour created by yeast action and promotes the digestibility of bread, enhancing the nutritive value of bakery products. 

The amount of salt:

• 1.75% - 2.25% weight of flour used 

• Or 30g per 1L of water used

• Note: The amount of salt should be increased during summer to prevent undesirable bacterial growth. Moreover, salt should never be dissolved in the same water with yeast as salt is antiseptic - it can dehydrate and kill the yeast cells.

7. Dairy Products and Eggs

Fats from milk and eggs improve the ability of the dough to retain gas and give the finished products a greater volume. These fat compounds can also lengthen the shelf life of bread. Lactose in milk caramelizes in the oven, producing bread with healthy crust color. Proteins in eggs can coagulate all baking ingredients at high temperature, so that the dough doesn’t collapse during baking. And last but not least, lecithin in the yolk helps the dough be smoother. 

• Amount of liquid dairy products (percentage of flour weight): 2% - 8%

8. Spices

The key to any signature bread is spice! Spices commonly used for bread-making include:

• Anise

• Caraway 

• Cardamom 

• Cinnamon 

• Cloves

• Ginger 

• Mace

• Nutmeg 

• Poppy seed

• Sesame 

According to a study conducted by Dr. Scannell from UCD’s Institute of Food and Health, the smell of freshly baked bread can trigger feelings of wellbeing, related to safety, family and home(5). It’s no wonder then that at the height of the pandemic we’ve returned to our kitchens for a source of comfort! 

If you’re interested in learning more about the science of baking, check out our upcoming event The Great Pandemic Bake Off: The Science of Baking with The Great Canadian Baking Show season 2 runner-up Sachin Seth! In the meantime, be patient with the bread-making process and enjoy experimenting until you crack your own perfect bread recipe.