It is February 2025. And yes, it’s been nine – NINE – years since I last wrote about this brioche study. And yet, it is one that I still think about often, perhaps because I never completed it, but also because I get emails, almost daily, requesting the parts that never were.
Naturally, I thought I’d start where we left off. For those of you who wonder, here is the first part, describing the approach of this study. And you’ll find the control recipe here, along with notes and pictures on oven spring, crust and crumb texture.
For an overview, click here: BRIOCHE STUDY OVERVIEW.
CONTENT TABLE
– Part II: the ingredients – this is where you are.
– Part III: the process – method, techniques and tips
– Recipe: brioche #1, the control
– Recipe: brioche #2, the almost Chavot-brioche
– Recipe: brioche #3, the pain au lait
– Recipe: brioches #4 and #5
– Part IV: impact of the egg-to-milk ratio in rich doughs
– Ressources: Brioche in literature
Explore the feature: A brioche study and follow our discoveries on instagram: #BRIOCHESTUDY.
Today, we’ll go through the ingredients, starting with eggs and milk and working our way down. The one question we’ll try to answer is:
How does each ingredient affect the rheological properties of brioche dough?
Rheology is the science of of the deformation and flow of matter under applied forces. It is widely used in the scientific community to deepen the understanding of how dough will behave during the bread-making process.
Dough has many rheological properties that can be studied using different methods, but we’re mostly going to focus on elasticity, extensibility, and strength. Other notable properties include resistance to deformation and viscosity.
1. Elasticity, the ability of dough to stretch and return to its original shape after being deformed or stretched.
2. Extensibility, the ability of dough to stretch without breaking. It is an essential property for shaping and forming the dough.
3. Strength is a function of both elasticity and extensibility. The more extensible and elastic a dough is, the stronger it is considered to be.
THE INGREDIENTS
Eggs
The eggs I use: Organic, weighing 50g each.
Eggs contain a variety of molecules that can affect the rheological properties of a dough:
– Proteins: egg whites and yolks contain different types of proteins, including ovalbumin, ovotransferrin, and ovomucin. These proteins can interact with gluten proteins in the dough, weakening the gluten network, leading to increased extensibility and decreased elasticity.
What does it mean for a finished baked product to have higher extensibility and lower elasticity?
Higher extensibility: a dough with higher extensibility is easier to stretch and shape. This is beneficial for certain types of bread, where a more extended shaping process is desired – for example baguettes, croissants, pizza…
Lower elasticity: a dough with lower elasticity means that the finished product may have a softer , fluffier texture. The crumb structure might be more open and airy because the dough doesn’t resist rising as much during fermentation and baking.
It can also mean that if not baked in a tin, the dough may spread more during baking rather than holding a tight, structured shape.
FOLLOW-UP QUESTION
Why is a dough that has just been mixed harder to shape than one that has rested?
A dough that has been recently mixed is often difficult to shape because the gluten strands are still tight; during the resting period, the flour absorbs more liquid and the gluten strands relax, making the dough more pliable and easier to shape. The resting period also allows enzymes in the flour to break down starches into simple sugars, which can be fermented by the yeast and improve the flavor of the dough.
At the same time, the egg proteins – especially albumin, the egg white proteins – provide additional strength and stability to the brioche´s crumb structure as they coagulate when the temperature reaches 80°C. In fact as the egg white protein set, they form a solid mass which gives additional structure to the bread, contributing to its overall volume.
It is also worth noting that the egg proteins also have a role in the organoleptic qualities of brioche. They do indeed participate in the Maillard reaction, also called non-enzymatic browning that occurs when proteins and sugars react under heat. This reaction contributes to the crust colour and the flavour of the brioche.
Organoleptic qualities
Organoleptic qualities refer to the aspects of a substance, that create an individual experience via the senses. This includes taste, colour, odour, and feel. These qualities are often used in the evaluation of food products, but also in other fields.
– Lipids: egg yolks are high in fat, which has a tenderising effect on the dough by interfering with its gluten development. By coating the gluten proteins and preventing them from forming a strong network, lipids make a dough less elastic and more extensible, leading to a more tender and delicate crumb in the final product.
The lipids in egg yolks also provides a richness of flavour.
– Emulsifiers: egg yolks contain natural emulsifiers, most notably lecithin, which helps stabilise the emulsion of fat and water in the dough. This contributes to a smoother, more uniform texture in the finished product.
Milk
The milk I use: 3% fat.
Whole milk is a complex liquid that contains several components, each of which can influence the rheological and organoleptic properties of dough in different ways:
– Water: the water in milk increases dough hydration, a fundamental point for both gluten development and starch gelatinization.
– Proteins: milk proteins, particularly caseins and whey proteins, interact with the gluten network. They can lead to increased elasticity. The amino acids from these proteins also participate in Maillard reactions during baking, along with the milk sugars.
What does an increased elasticity mean for the finished baked product?
Increased elasticity in a dough can lead to:
– a denser crumb: as the dough resists rising during fermentation and baking, the brioche will have smaller, more evenly distributed air pockets.
– a structured shape: the dough is more likely to hold its shape during baking, even if not baked in a tin. This is because a dough with increased elasticity resists deformation and tends to spring back to its original shape.
– a chewier texture: on a molecular level, highly elastic doughs often mean a more tighly-wound gluten matrix, which makes for a firmer, chewier texture.
FLour
The flour I use: Swedish plain flour, averaging at 10% protein content.
Flour is the primary structural component of brioche dough. Although you could possibly make brioche from virtually any flour containing gluten-forming proteins, we will stick to plain wheat flour today.
FOLLOW-UP QUESTION
How is the best way to incorporate whole grain flours in brioche? And how far can you push the substitution?
Whole grain flours are ground from whole, unprocessed wheat kernels, grains, or seeds. Unlike refined flours, such as plain flour, whole grain flours include the germ and bran, which are more absorbent (the bran is rich in pentosans, a family of polysaccharides that can absorb up to 15 times their weight). In practice, this means that the total dough hydration needs to be increased to allow for gluten development.
In her fantastic newsletter, Nicola Lamb, writes that one can substitute around 30% of the total flour by weight. She also mentions a wonderful technique, which I’ve also been partial to, which consists in separating the bran, and soaking or cooking a porridge before re-incorporating it in the dough. This way, you get the wonderful nutty flavours of whole grain flour without it being detrimental to gluten development.
Read more here: https://kitchenprojects.substack.com/p/kitchen-project-38-tart-tropezienne
TO DO: test different brioche doughs made using whole grain flours.
– Proteins: the most important proteins in flour – both for their function but also by their occurrence – are glutenin and gliadin. These two proteins are the building blocks of gluten – when water or a liquid containing water, like milk or eggs, is added to these proteins, they link together, forming gluten.
Glutenin gives the dough extensibility, while gliadin contributes to its elasticity.
The protein content in flour varies greatly depending on the type of flour. The one I used: kärnvetemjöl, has a protein percentage of 10% – the standard for Swedish plain flour, slightly lower that English or American all-purpose.
Although, the protein content in flour is crucial, it can also be misleading – some flours can be rich in proteins but relatively poor in glutenin and gliadin. However, on paper, higher protein flours can absorb more water and form a stronger gluten network, resulting in a dough with greater elasticity and strength. This means the dough can stretch more without tearing, allowing it to trap the gases produced during fermentation and rise effectively.
FOLLOW-UP QUESTION
How does the protein content of flour affect the rheological and organoleptic properties of brioche – both dough and finished product?
In order to answer this question concretely, we’ll need to conduct a new mixture-design experiment, with the protein content of flour as a variable.
TO DO: test different brioche doughs made using flours with varying protein content.
– Starch: forms around 70-75% of flour. It absorbs water and swells during baking. This process is called gelatinization. As gas bubbles in the dough expand and eventually burst to form a porous structure, the starch gel and coagulated gluten matrix surrounding these bubbles increase in viscosity, forming a firm structure, essential for setting crumb structure and texture.
Sugar
The sugar I use: plain caster sugar.
Caster sugar is made of sucrose, a disaccharide that affect both the rheological and organoleptic properties of brioche.
Sugar significantly influences the taste and colour of the finished product. It enhances the sweetness, and contributes to a golden-brown crust through the Maillard reaction that occurs during baking.
Sugar also affects the crumb texture. In fact, the hygroscopic nature of sugar allows it to absorb moisture and retain it over time, resulting in a softer loaf.
hygro·scop·ic
adjective
(of a substance) tending to absorb moisture from the air.
Of course, sugar acts as food for the yeast in the fermentation process.
FOLLOW-UP QUESTION
How do different proportions of caster sugar in the dough affect the finished product?
I feel like it would be a fun experiment to conduct a mixture-design using sugar as a variable.
TO DO:
– test different brioche doughs made using varying levels of caster sugar in the formula
– read the following reasearch paper: Timmermans, E.(2022). Sugar Levels Determine Fermentation Dynamics during Yeast Pastry Making and Its Impact on Dough and Product Characteristics. Foods, 11(10), 13881
Salt
The salt I use: both flaky sea salt and fine salt.
It’s worth noting that different salts have different volumes, making it difficult to substitute flaky salt for fine salt if using spoon-measures. By weight, I’ve found that there is virtually no difference between these two salts, however, certain salts, like Himalayan salt are much less salty.
Salt strengthens the gluten network in the dough, which improves its elasticity and extensibility. This results in a dough that is easier to handle and shape.
It also regulates the rate of yeast fermentation by slowing it down.
And perhaps most importantly, salt enhances the flavour of the brioche.
Yeast
The yeast I use: fresh yeast.
Substituting fresh yeast
For 10g of fresh yeast, use either 5g of active dry yeast (approximately one teaspoon: 5mL) or 3g of instant yeast (a heaped half teaspoon: 2.5mL). Note that the active dry yeast should be rehydrated in warm water or milk (around 40°C) for 5 to 10 minutes; however, both fresh yeast and instant yeast can be weighed out along with the flour, and used as is in the recipe.
Note: If making a very wet dough with over 80% hydration, I tend to crumble my fresh yeast to make sure it gets fully incorporated; otherwise, I just leave it into large chunks and let the kneading do the job.
Fresh yeast is made of Saccharomyces cerevisiae cells. In the right settings, yeast will convert sugar and starch into carbon dioxide and alcohol – this process is called fermentation.
FOLLOW-UP QUESTION
How does fermentation time affect the qualities of the finished product
I would love to test one brioche dough and see how far we can push the fermentation.
TO DO:
– make a dough and test different fermentation times under constant settings like temperature and humidity
FOLLOW-UP QUESTIONS AND NOTES
1. Tangzhong method
How does adding a tangzhong (a cooked flour-water paste) alter the hydration and softness of brioche?
– Experiment: Test a brioche with and without tangzhong and compare moisture retention over time.
– Suggested reading:The Food Lab by J. Kenji López-Alt (discusses hydration techniques in bread baking).
2. Pre-ferments
How does using a pre-ferment (such as a poolish or sponge) change the flavor complexity and structure of brioche?
– Experiment: Make three brioches: one with direct yeast addition, one with poolish, and one with a stiff biga.
3. Impact of hydration on brioche crumb
How does altering the hydration level affect the crumb structure and softness? How much can hydration be increased while maintaining dough integrity?
4. Effects of the cold fermentation
How does a long cold proof (12-48 hours) change the gluten structure and overall rise compared to a same-day bake? Is the ideal proofing time different for dough with pre-ferments?
5. Butter incorporation methods
Should butter be added in one stage, or would gradual emulsification affect texture positively?
Experiment: Compare direct incorporation vs. gradual mixing at different butter %.
6. Dough temperature before baking
What is the optimal final dough temperature before baking?
and the one I made 
