Bulk Fermentation Explained | Why Proof Bread Twice?

Published on
20 October 2020
Gareth Busby
Gareth Busby

After the dough is kneaded, the next step toward fantastic bread is bulk fermentation. In this stage, the dough is left to rest, where it undergoes several natural processes which mature its structure and flavour. Bulk fermentation is completed when the baker is happy that the dough has developed sufficiently. After this, it is moulded into its desired shape before it undergoes its final rise. Typically, bulk fermentation lasts around 2 hours, but it can change drastically between bread types. For example, sourdough bread is usually 4-8 hours as a minimum- yet it can be much longer!

Many new bakers wonder, “what happens to the dough during this time?”, “Why proof bread twice?”, “What is the point of a first rise?” and “Do you need to bulk ferment bread dough?”. Well, if you are asking the same questions or are looking for a complete guide on bulk fermentation, you’re about to get it! This guide discovers what is bulk fermentation for sourdough and yeast-made bread and everything you need to know about the topic.

What is bulk fermentation?

Bulk fermentation, also known as the “first rise”, is a key stage of bread production. During this process, the dough is matured through enzymic activity, hydrolysis, alcoholic fermentation derived from the yeast, and the fermentation of lactic acid bacteria. These processes add maturity to the dough, and little manual intervention is required if the ideal conditions are available.

Why proof bread twice?

Proofing is split into two rises, a first rise called bulk fermentation and a second, final proof. So why not just do one long rise? Well, this will become more apparent as you go through this article, but the overarching difference between them is the approach of the baker:

Bulk Fermentation: Dough matures flavour, conditioning properties and preparing the gluten structure.

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The dough is then divided, preshaped, bench rested and final shaped.

Final Proof: Gas expands the pockets of gluten, making the bread rise.

The same things occur in both the first and second rise. The difference is that the dough is more mature during the second rise, allowing it to capture the gas produced by the yeast more formidably. When the dough is shaped, gas is pushed out and the gluten structure is realigned. Shaping and preshaping forces the dough to rebuild using its enhanced properties, helping it to rise into its expected shape in the second rise.

What happens during bulk fermentation?

As soon as yeast cells come in contact with water and sugar (developed from the flour), they begin the route to produce carbon dioxide gas. It utilises one of two routes:

  • Respiration in the presence of oxygen (aerobic) to produce carbon dioxide, water and lots of energy.
  • Respiration without oxygen (anaerobic), which leads to alcoholic fermentation, where carbon dioxide, ethanol and small amounts of energy are produced.

Bulk fermentation also facilitates the development of lactic acid bacteria. These bacteria naturally occur in the flour or the environment and multiply in the right conditions. The lactic acid bacteria follow homofermentative and heterofermentative processes to produce many products, mainly: lactic and acetic acids, ethanol, and sometimes carbon dioxide.

fermentation and respiration routes

I’ll discuss their benefits in a moment, but for now, we’ll go back to the start of the fermentation process.

How flour changes during bulk fermentation

As soon as the flour is hydrated, its starch particles break down into simpler sugars through a process known as hydrolysis. Enzymes released by the yeast and the flour will speed up (catalyse) this activity. The simple sugars produced, called monosaccharides, can then be processed by the yeast.

Another important part of the process is the development of the gluten matrix. Once hydrated, the majority of the proteins in the flour transform into gluten. To start with, gluten strands are tangled up in coils and provide little strength to the dough structure. As the strands soak up water and are agitated through kneading, they become stretchy and extensible.

The gluten “bonds” to itself in a more helpful, defined structure over time. We call the structure the “gluten matrix” or “gluten network”. As gluten interlocks, gas gets stored in pockets between the strands. These continue to fill with gas which stretches the structure. The result of all this is, of course, the dough rises.

To speed up gluten development dough can be kneaded. A gentle dough kneading technique accelerates the hydration of the gluten and starch. Whereas a more aggressive method improves the bonding of the matrix and incorporates more oxygen.

During bulk fermentation, the gluten matrix matures as the dough sits, yet development is often accelerated by using one of the stretch and fold techniques shared in a moment.

What changes during bulk fermentation?

Several changes occur as bulk fermentation continues. Most of them are good, yet some are undesirable depending on the product being made. Here are the majority of changes that occur in the dough and how they affect the bread:

The changes on dough over time during fermentation

Oxygen is incorporated into the flour

Oxygen latches to the dough when they are in contact. Some flour oxidation is great for bread. It helps to strengthen the gluten bonds, which aids the dough’s strength, elasticity and machinability. A nicely oxidised dough will hold shape and is easily moulded into its final design.

During bulk fermentation, the dough continues to absorb oxygen, albeit at a slower rate than when it is kneaded. Too much oxygen is a problem as it can destroy the flavour of the bread by breaking down the carotenoid pigments in the flour. Over-oxidation is known as bleaching of the flour. Carotenoids contain minerals that contribute to much of bread’s “bready” flavour and colour. The result of bleaching the flour is a less nutritious, bland-tasting, smelling loaf.

Dough that is bulk fermented for a long period runs the risk of becoming over-oxidised. This is why kneading should be short and gentle when making long-fermented bread. Gluten development will primarily occur during the first rise instead of the mixing bowl. For quick-bread, intensive mixing is used to achieve 100% gluten development at the end of mixing, and the heavily oxygenated dough goes straight into final shaping and proofing.

Flavour increases

When oxygen is available, yeast respires aerobically. This is where it produces CO2 and water without any of the products that occur during fermentation. When oxygen levels deplete, yeast will respire anaerobically, and fermentation occurs to produce flavourful products such as ethanol, lactic and acetic acids.

As fermentation continues, more complex carbohydrates are broken down into sugars. Some of them will provide food for the yeast, whilst any unused add sweet flavours and caramelisation during the baking process.

Note: The caramelisation of the crust perfumes the whole loaf to influence the flavour of the bread in a big way!

Gluten network matures

Gluten naturally matures as the proteins soak up water. Alongside this, enzymes such as protease, acids and cereal amylases break down the gluten and its bonds to rebuild the matrix.

Gas retaining properties are enhanced

The enhanced gluten structure is fortified by ethanol and organic acids which enhance the glutens’ ability to stretch. They also make the dough less resistant to tearing (machinability). It can also mean that the dough is more elastic and, therefore, better at holding its shape during the rise. The effect of this depends on the qualities of the flour and the processes used. A mature dough structure captures more gas as it rises and during oven spring. An airy interior produces a light crumb texture and a crisper crust.

Gluten extensibility changes

Extensibility is a measure of the dough’s ability to stretch without tearing. It’s controlled by the ratio of gliadin gluten (opposed to the glutenin variety), the quality of the gluten, and the bonding between them.

During the first rise, gluten extensibility is initially enhanced as it is hydrated. Yet as the bulk rise continues, lactic acid numbers increase, which breaks down gluten. This, combined with the previous point, means there is a sweet spot where extensibility increases to its maximum before it begins to decrease. For this reason, it is best to use other methods to boost extensibility, such as:

  • Autolyse without salt before mixing
  • Selecting flour with higher levels of gliadin
  • Using the right amount of water for the best dough hydration

Gas is produced

Gas is primarily produced by the yeast by respiration and fermentation. Heterofermentative reactions provided by Lactic Acid Bacteria (LAB) can also produce CO2 as well as lactic and acetic acid. Gas produced by LAB in yeast-leavened bread will account for less than 10%. In sourdough bread fermentation, because LAB outnumbers the number of yeast cells by up to 100 to 1, LAB fermentation accounts for around 50% of carbon dioxide production.

Gas produced during bulk fermentation may benefit the dough as it stretches the gluten matrix. Though this is a theory I cannot confirm with scientific proof, let me know in the comments if you agree or disagree!

Is gas important during bulk fermentation?

The same things happen during the first and second rises. Whilst gas production is not always desired in bulk fermentation, it happens anyway. In some bread types, a large amount of gas is produced during bulk fermentation, followed by a short final rise. The gas is retained in the gluten structure through gently shaping and preshaping to produce an irresistible open crumb. Gas produced during the first rise may also benefit the structure by stretching the matrix.

The life of the bread is extended

Acids lower the dough’s pH value, which helps mould resistance in the bread. Ethanol produced by yeast fermentation makes the bread inhospitable to unwanted bacteria and fungi. These products also slow starch retrogradation, responsible for the bread losing moisture and becoming stale.

A darker crust is produced

Cereal enzymes break down proteins in the flour. They change the protein in the dough to reveal more free proteins available for Maillard reactions. In the oven, Maillard reactions occur when proteins and sugars are heated to brown the bread crust. A more mature dough will have more available sugars and proteins, therefore having a darker crust and a wider range of colours.

One way of determining the length of fermentation of bread that has been baked is by inspecting the colour of the crust. Bread that’s undergone a short fermentation period has a bright orange crust. Long-fermented bread will be darker brown and even black in some places. The caramelisation of the crust produces an aroma which perfumes throughout the bread.

The crumb structure becomes more irregular

The acids in the crumb structure repel each other, which causes pockets of weakness to appear in the gluten structure. After baking, this leaves behind larger air pockets in the crumb that are irregularly spaced.

How to bulk ferment the right way!

We’ve covered what happens to the dough when bulk fermenting, so how do you bulk ferment dough the right way? Here are my top tips to make the perfect loaf:

1- Use the right sized container

When selecting a container, use one made from food-safe material that’s big enough to cope if the dough doubles. A container that’s far too big can also be detrimental. An oversized container contributes to more oxygen being absorbed into the dough. This will over-oxidise or dry out the dough. They are also harder to clean! For small, two or three loaf batches, these are the containers I recommend:

Not only are they the perfect size, but as they are transparent, you can watch your dough grow easily!

2- Prepare the fermentation area

Yeast and the enzymes responsible for breaking down starch become more active when warm and humid. For the best quality dough, ferment at a temperature that doesn’t fluctuate. You should notice improvements in your bread when a consistent bread proofing temperature is used. The dough will rise quickly, and the gluten matrix will be better structured.

I recommend fermentation temperatures of around 25-28C (77-82F)for medium to long bulk rises. Or a bit warmer, such as 32-38C (90-100F), when fermenting quickly. It is also possible to place the dough in the fridge to slow fermentation. We’ll discuss this later on. One of the best ways to facilitate temperature control is to use a proofing box like this one from Brod & Taylor:

Brod and Taylor home proofer

Being able to control the proofing environment of the dough is a fantastic feeling as it removes any worry about cold weather. A cold dough takes longer to mature. By using a proofer, you can make bread faster, be more accurate with timing, and make better bread! Here’s a link if you wish to get yours direct from Brod & Taylor, or here for Amazon.

If using this proofer, you will have to use a container that’s under 20 cm high. This 2.5litre tub should work.

3- Oil or flour the container

Whilst it’s not essential to line the container with a bit of oil or flour, it’s a good idea. A barrier between the dough and the tub makes it much easier to remove the dough in one piece. This is vital when preparing bread such as campaillou, which skips the second rise, so it must come out in one mass.

A light lining of flour or a drop of oil spread to cover all areas of the container is required. Oil is generally preferred, especially for high hydration doughs, as it does not get absorbed into the dough as easily. Spray oil is excellent as it is easy to apply in small amounts.

Traditional French bakers don’t tend to use oil when making lean bread. French bread recipes use flour to line the container.

4- Add the dough to the bowl

When making several loaves at once, people often ask whether they should divide their dough into loaf weights before bulk fermentation. The answer is no. Dough is always divided at the end of bulk fermentation. Aside from “bulk” being in the name, larger batches of dough are faster to rise and produce better flavour due to the mass effect.

Place the dough into the container in one piece, if you can. You can scrape the edges of the mixing bowl and add any bits of dough to the container if you wish.

Place the dough into the container in one piece, if you can. You can scrape the edges of the mixing bowl and add any bits of dough to the container if you wish.

5- Mark the bowl height

Mark the container

Using a marker, mark the original height of the dough. Then, taking a ruler or tape measure, add another line at 50% increase, 100%, or whatever height you are aiming for. As the dough produces gas, it rises. Once it reaches its target height, the bulk fermentation stage is complete. If you are not sure how much it should rise, go with 50%. The target rise level is discussed later on in this guide.

Marking the dough’s start and target point makes it much easier to check how your dough is progressing. It makes the whole process more relaxed and enjoyable!

6- Cover the container

The container should be covered to stop moisture from exiting the dough. Otherwise, its surface will dry and form a skin. Reducing the airflow also means less oxygen will be introduced, thus, extending the amount of time the dough can be fermented. An airtight cover also prevents it from fruit flies and other curious insects!

If the container you are using has a lid, use it. If not, some plastic wrap is ideal. A plate or flat box can also work -if there is a reasonably good seal! Tea towels are too porous, and whilst they can be used for quick first rises (1-hour max), a more airtight solution should be selected for most doughs.

7- Stretch and fold

Stretch and folds redistribute the sugars and yeast in the dough. This makes it easier for the yeast to consume the available sugars and so accelerates the rate of respiration and fermentation. The benefit of stretch and folds includes reducing the length of the first rise whilst enhancing the gluten structure. This enhancement comes from agitating the gluten network to form new, stronger bonds.

Other fermentation products combine with stretch and folds to mature the gluten. The result is the dough structure gets progressively stronger as the first rise continues. There are many methods to stretch and fold, varying in their impact on enhancing the gluten structure. Here is the most simple one:

Repeat folds during bulk fermentation, until the dough feels strong and hard to stretch. Don’t worry about gas escaping when you stretch and fold. It’s going to happen, so just embrace it!

How long should I wait between stretch and folds?

Allow the dough to rest between folding to allow the gluten to relax and bond, ready for the next stretch and fold. It’s best to leave it around 30 minutes between each rendition, but for yeast-heavy doughs that undergo a short first rise, 20-minute intervals can be considered. For slower doughs such as sourdough, 60-minute intervals can be preferred, but some bakers like a higher frequency. It’s best to be consistent with the time between stretch and folds.

8- Check when it is ready

For a basic test for doneness, watch the height of the rise. Once the dough reaches the target height you drew on the container, it should be ready for shaping. There is more to consider regarding when the dough is ready, so guess what the next topic will be?!

9- Divide and preshape

Once you are happy that bulk fermentation has finished, move on to the dividing a moulding stage. If you are making more than one bread from your batch, divide the dough into pieces. You will then preshape them, typically into rounds or batard shapes, and leave your dough to rest on the work surface for 15-30 minutes. After this, it’s time to shape your dough for the final time and put it in its proofing container (such as a banneton or bread tin) for its second rise.

How to adjust the speed of bulk fermentation

Bread made slowly tends to be deep-flavoured, interesting and highly welcome. Whether you want a long-fermented dough or a short one, these factors will determine the length of the first rise:

  • Humidity
  • Temperature
  • Hydration levels of the dough
  • Development of the gluten during mixing/autolyse/S&F’s
  • The levain used
  • Amount of levain
  • Amount of salt
  • Oxygenation levels
  • Use of prefermented flour

Temperature and humidity are the most challenging of these factors to control. This is why I recommend a proofer -remember the Brod & Taylor?

Tip: Prefermented flour reduces the bulk fermentation time by adding flour that has already been fermented. To do this, a portion of the flour in the recipe is soaked in water with a small quantity of yeast. It takes around 12-18 hours to mature. The preferment is then added with the other ingredients at the start of mixing. Prefermented levains include Sourdough, Poolish, Biga and Pâte fermentée.

Does autolyse impact bulk fermentation?

Autolysing the flour before kneading allows it to be hydrated much earlier on. Through the enzyme protease, autolyse breaks down the peptide bonds, making the dough more extensible. Because the flour is hydrated, the gluten begins to mature earlier, and simple sugars are produced before the yeast is added. This means bulk fermentation time can be reduced. Depending on the length of the autolyse, it is wise to consider fermenting the dough at a warm temperature. This will allow yeast fermentation to catch up with gluten development.

Fermentolyse is a method that incorporates the salt and the yeast into the autolyse. It’s like a mini-bulk fermentation before the dough is kneaded and a great way to reduce kneading time without making the gluten overly extensible!

How do you know when to end bulk fermentation?

Deciding how long to bulk ferment a dough is tricky. You’ll also need to change the amount of development to suit different styles of bread. Yet, if there is one thing I would implore you to take away from this article is that is no perfect time to end bulk fermentation. It’s more a matter of “about right”. Many factors of the dough will improve with time, whilst others deteriorate.

It’s best to check at regular intervals throughout bulk fermentation. The two most important features are the height of the rise and comparing gluten development:

The target height of the rise is achieved

The most popular measurement to monitor is the height of the fermenting dough. This displays how much gas has been produced by the yeast. Letting the dough rise too much could lead to the yeast exhausting its sugar supply and not fully rising during the final proof. A 50% height increase from its original height is common for most recipes. Some recipes require less, and some, more.

Checking fermentation with an aliquot jar?

There is a trend that resurfaces every now and again for bakers to remove a piece of dough at the start of bulk fermentation and place it in an aliquot or small jar. The jar is marked with a target rise height with a marker or elastic band. The height of the rise is then tracked in the jar instead of the container method described above.

This can be a sensible solution if you are using a bowl or opaque container to ferment your dough. But it doesn’t consider degassing during stretch and folds, nor the other factors discussed above. I find it a bit pointless but feel free to utilise it alongside the other tests if you wish!

Stretches without tearing (gluten development)

Mature dough should stretch thinly without tearing. When it shows these qualities, the gluten will stretch and retain gas with maximum efficiency. Perfect for a well-risen loaf! To test. You can just give the dough a tug and see if it feels like elastic whipped cream: strong, elastic and pillowy. But a more accurate check is the windowpane test.

Use your hands to stretch out a section of the dough. If it stretches thinly without tearing, then it passes the windowpane test. If it tears or has little stretch, it has not reached 100% gluten development and so requires a longer bulk fermentation.

See: Why won’t my dough pass the windowpane test?

Splitting bulk fermentation into two stages

Some bakers divide bulk fermentation into two sections. In the first, they’ll stretch and fold their dough intensively. This can be an extension to or in replacement of kneading. In the second stage, the dough is simply left to rest.

The beauty of this method is that you work the gluten well until it almost passes the windowpane test and then let the dough mature in the second. It kinda makes the process easier. Myself? I usually stretch and fold continually through bulk fermentation. There is no right way. It’s down to the bread recipe or the baker to choose.

Managing volume gain vs gluten extensibility

Gluten development and volume increase during bulk fermentation. The idea is that both developments are closely aligned. The dough shouldn’t reach its target height when the gluten structure is still weak, or vice versa. In either situation, it would lead to a less-risen bread that’s likely to be dense and unappealing.

If one factor is ahead of the other, changes can be made to allow the get them to catch up. It takes experience to master this, but I’m sure after a few attempts, you’ll start to notice what you are looking for and how to counteract the problem before it’s too late. The basic tweaks are described in the table below:

Gas productionGluten development
To accelerate:Increase the temperature of fermentation– Cool the dough
– More frequent stretch and folds
– More aggressive stretch and fold techniques such as the envelope fold
To slow down:Decrease the temperature of fermentation– Fewer stretch and folds
– Switch to a gentler stretch and fold technique

Other factors concerning ending bulk fermentation:

Yet gluten development and height of the rise aren’t the only things to look out for when deciding when to end bulk fermentation.

– Larger gas bubbles appear

Dough rises when gas bubbles are produced. Bubbles can be big or small, varied or uniform and remain to form the structure of the crumb after baking. You should see small bubbles at the start of fermentation, and the larger ones will increase as time goes on. Some types of bread benefit from large air bubbles. Others prefer smaller, more uniform bubbles and, therefore, less fermentation.

However, many other variables influence the size of the air bubbles. Gluten strength, flour performance, additional protein, amount of levain, emulsifying additives, oxidation and handling skills can impact the size of the bubbles. Check out a book such as the taste of bread if you would like to learn more.

– The dough “jiggles”

The amount of gas in the dough makes it lighter to handle. When making a well-fermented dough, give the container a sideways shake. The dough should jiggle just enough to show movement, but not so that it flies out the bowl!

Note: If looking for less maturity, the dough shouldn’t reach the point that it jiggles. It depends on what you want to achieve- more on this later.

– A domed surface

How the dough sits in the container is a great way to tell if the dough has finished bulk fermentation. A slightly domed surface that comes away from the edges of the container is the perfect scenario.

Fermentation accelerates over time. Most bakers quickly learn to check their dough more frequently during the later stages of the process!

– Smells aromatic

As acids, acetates, ethanol and other organic compounds multiply, a mature dough will be nicely perfumed. Smelling the dough is a great way to confirm that it has bags of flavour – if that is what you are looking for!

– Temperature increases

Many professional recipes use temperature as the primary method to determine maturity. As fermentation continues, the dough’s temperature will increase to reach a target temperature. This method works very well, providing that the desired dough temperature is achieved at the end of mixing, and a proofer is used to control the proofing temperature.

We also may have other constraints, such as timing several dough batches to arrive at the oven at the right time. Bottlenecking at the oven can occur when there isn’t enough oven space to bake the bread that is ready. Fitting baking bread around everyday life can also be challenging at home. As you get more experienced, you’ll learn to stop worrying about perfection, as “about right” is perfectly satisfactory in most cases.

The impact of temperature during bulk fermentation

For a shorter rise and a lighter flavour, bread should be bulk fermented at 32-38C (90-100F). To enhance organic acid and ethanol development, ferment the dough between 25-28C (77-82F). Give it some time in the fridge for sweeter-tasting bread without adding sweeteners.

Yeast operates fastest when warm. As temperature increases, yeast activity improves with a 10% increase per 1C gain. Once the yeast reaches 141F (60C) (in the oven) it becomes permanently deactivated. However, if the dough is above 40C (104F) it will be too warm for enzymes to break down the necessary starch to keep up with the increased yeast activity. Despite an initial surge, the yeast will soon run out of sugars and gas production will cease.

Fermenting dough at warmer temperatures (above 32C or 90F) can lead to gas production surpassing gluten development. The gas produced will not be retained in the immature gluten structure, and the dough will not rise effectively with the likelihood of it collapsing or the bread being dense. This is why high proofing temperatures should be reserved for well-kneaded dough and why no-knead bread utilises cooler temperatures.

The temperature of fermentation impacts the rate at which certain enzymes operate. This is nick-picking, but professional bakers will tweak proofing and bulk fermentation temperatures to unleash different flavours in the bread.

Fools crumb: A running issue with bread is when holes run through the centre of the crumb. It is often referred to as “fools crumb”, where the dough is too weak to capture the gas produced evenly.

Bulk fermentation in the fridge

Many bakers use the refrigerator for all or part of bulk fermentation. Cold temperatures slow down the activity of the yeast and, therefore, gas production. Enzymes are also less active when cold. However, starch continues to be broken down into sugars through hydrolysis. This is the natural breakdown of the sugars and proteins when soaked in water.

Fermenting dough in the fridge leads to the development of sweet and exciting flavours. Browning of the crust is further enhanced through more sugars being available for the Malliard process as they are not all consumed by the yeast.

As well as structural benefits, fridge fermentation, often called retardation, helps bakers manage their timings and avoid early starts. A typical fridge fermentation is overnight – about 10 hours. Some bakers use the fridge to store a large batch of dough in bulk to divide, proof and bake fresh the next day. Others might proof their shaped loaves in the fridge.

Fridge bulk fermentation vs fridge final proofing

The gluten structure continues to strengthen when cold, yet fermentation activity is almost non-existent. When overnight retarding, less kneading and/or stretch and folds are provided to avoid the gluten overdeveloped.

Dough will still need some time at warm temperatures. It’s impossible to ferment or proof dough 100% in the refrigerator. Some gas production is required, and it needs to be warm for this.

Chilling dough during bulk fermentation leads to more gluten development. This is especially handy for sourdough and no (or lightly) kneaded doughs. Shaping of the dough can only be done when there is enough gluten development at the time (for it to stay in shape). To improve gluten strength, put the dough in the fridge. Retarding the dough during the final rise provides alternative benefits:

  • Dough can be left overnight to be baked early in the morning (without having to work overnight)
  • Bubbles appear on the surface of the crust
  • If chilled when almost proofed, organic acids multiply to provide more flavour and sourness in sourdough bread
  • The strength of the bread’s structure is further enhanced

Do I need to let cold dough warm up before shaping?

If your dough comes out of the refrigerator for shaping, it will be pretty cold. It might be uncomfortable and hard to stretch into shape, but you don’t have to let it warm up before dividing and shaping. But if it is too hard to work with, you can let it warm up for an hour or two.

Do I need to let cold dough warm up after fridge proofing?

You can bake bread straight from the fridge. However, the core of the bread will take longer to bake through. There is no problem baking small-diameter loaves and rolls from the fridge, but you might want to wait for larger loaves to warm up before baking.

Avoiding the middle ground – keep it warm, or cold

Because of the temperature range enzymes operate, it is best to avoid proofing bread between 8-20C. This area is what I call “The middle ground”. There are no advantages to fermenting bread dough at this temperature range as enzymes and yeast have little activity. To enhance the gluten structure it is better to cool the dough entirely by using the fridge or more stretch and folds. When a fridge is unavailable, proofing in this range is a necessary solution to slow yeast activity, but I would not plan to do so.

How much development do I want from bulk fermentation?

While it’s easier to think of time as the determining factor of fermentation maturity, it’s a balance between time, humidity, mineral activity, temperature and gluten development (kneading/stretch and folds). As time is the most accessible variable to control when we make bread, we often use the length of time to determine the intended level of maturity.

The final proofing conditions should be taken into account too. For example, dough that will undergo a lengthy final rise in the fridge will require less maturity during bulk fermentation. The table below displays how I class short, medium and extended durations. As previously discussed, the growth of the rise is a great indicator. However, duration and growth don’t necessarily need to match.

Temp – 25C (F)DurationGrowthGluten Dev*
No bulk00%100%
Short maturity½ -2 hours25%100%
Medium maturity2-4 hours50%90%
Extended fermentation4+ hours100%85%

*Expected gluten development is based on the length of the second rise being close to the first.

If the first rise is conducted at a cool temperature, there might only be around 25% growth after 4 hours. Likewise, if a lot of yeast and warm temperatures are used, a 100% growth can quickly occur in a shorter period. But what level of development do you want from bread at the end of the first rise? That’s the next topic!

Comparing volume gains during bulk fermentation to the finished bread

I ran an experiment to share the impact of adjusting the length of bulk fermentation of a yeast dough. I made a large batch of dough and separated it into 4. One would be shaped right after kneading, the second would rise 25%, the third 50%, and the fourth would rise 100% (double) before it was shaped. For shaping I preshaped, bench rested for 20 minutes, final shaped and then proofed in a bread tin until they’d reached an identical height. A single slash was made and then each loaf was baked.

You can see examples of the bread shown below. See how the crumb size and colours change with the longer rise. It’s hard to see in the image, but the crumb got progressively whiter as fermentation time increased. This was likely due to oxidation. You’ll notice that the loaves gained a bigger rise in the oven when more mature. Flavour-wise, they all had a similar flavour, but the mature loaves had a deeper, much more enjoyable aroma and a lighter texture.

Comparison after baking

But this experiment didn’t take into account that a shorter bulk fermentation period requires more kneading to develop the gluten structure. So I ran the test again, this time removing the dough at different stages of the kneading process:

Dough NumberHeight Of RiseKneading Gluten Development
1090%
225%75%
350%50%
4100%25%

These adjustments made a considerable difference to the quality of the bread. Although I didn’t quite master each one, the differences in flavour and texture of each loaf were more suited to taste, than a clear better or worse.

Loaf 1 was smaller, had less flavour than the others with a really even crumb structure. Some additional fat or sugar would have enhanced this loaf.

Loaf 2 was superior in texture to the first. It tasted light but very morish. My girlfriend’s favourite.

Loaf 3 had a slightly stronger flavour than the previous ones and had the most irregular crumb. It was my favourite.

Loaf 4 had a deeper flavour, largely due to the caramelisation of the crust. There was a larger range of colour that occurred on the crust during baking. It was more spongy and moist, with an oily texture. Flavour was enjoyable and more aggressive in this one.

Comparison where kneading was adjusted

My findings from this experiment were that flavour definitely improves as bulk fermentation is extended. The flavour of the flour unlocks when it is fermented. Fat or sugar could be included in bread that is not fermented to boast flavour and enhance its texture. A short 25% bulk fermentation unlocks enough dough maturity to produce perfectly acceptable bread. The enhanced maturity that occurs when the dough doubles in size before shaping leads to a moist crumb and more browning in the oven.

When should I extend bulk ferment?

A long bulk rise matures the dough and produces bread full of flavour. This makes more interesting textures and tastes and is a popular route for artisan loaves. You can take this further in sourdough bread baking by comparing the San Francisco style to the French Pain au levain varieties. San Francisco sourdough bread is darker. It has a thinner, blistered crust and an acidic twang. These characteristics combine warm fermentation temperatures and time in the fridge.

Pain au levain is a lighter, fruity bread with a golden crust and no blisters. In fact, it is my understanding that a blister is viewed as an imperfection in France! This bread gets its features due to a slightly cooler room temperature fermentation and a short development time.

When is short fermentation best?

Quickly made bread doesn’t have to be bad. I actually quite like short fermented bread. When made well, it has a softer texture and a lighter taste that’s perfect for fillings to be the star of the show.By utilising a short or zero-time first rise, the yeast has more opportunity to respire aerobically. This is where carbon dioxide is produced without ethanol or organic acids.

The result is a lighter-tasting bread that rises quickly -similar to sliced bread in the stores. This bread should be kneaded intensively to develop the gluten structure and incorporate oxygen. You’ll want to achieve 100% gluten development by the end of kneading.

Oxidising agents such as ascorbic acid are often used alongside other dough improvers in commercial bakeries. These compensate for the lack of organic acids and ethanol maturity.

How to bulk ferment croissants?

Croissant dough is unique as it needs an extensible yet robust gluten matrix, some organic acids and few air bubbles. The dough is rolled out and must be mature enough to contain the layers of butter. Another challenge for croissant dough is that there should also be enough yeast to raise the heavy dough. The dough, therefore, contains a high quantity of yeast. It is kneaded to a low to medium level before placing in the fridge to cool down. The butter can then be added, and layers built up by rolling and folding.

How to bulk ferment rye bread?

Rye flour is not a form of wheat. Whilst it does contain protein, it does not behave like gluten. The pentosan proteins soak up water to produce a gum structure to capture the gas. As a dough containing rye flour ferments, the pentosans are broken down, which release water. This makes the dough sticker and can often collapse as it rises or in the oven.

Rye flour needs only to be kneaded gently, and bulk fermented slowly when made with yeast. Acids in a sourdough starter protect the pentosans from the enzymes wanting to break them down. This means rye flour leavened with rye flour can be fermented for longer to create a lighter bread.

Can dough over ferment?

Sometimes, whilst bulk fermenting, we go canoeing, get caught in a tidal drift and return later than expected -yes, me. On return, we’re too late, and the dough is over-fermented. In this instance, get the bread shaped as soon as possible or flatten it into an oiled tray to make focaccia. Of course, this can happen when you are watching your dough too. The trick is to learn what the dough should look like when it’s ripe and what to avoid. Signs of over-fermentation:

  • Visible bubbles full of air on the surface
  • Collapses with the slightest touch
  • Too gassy to mould properly
  • An extra strong whiff of alcohol
  • Sticky
  • Weak gluten
Dough that is over-fermented

A dough is over-fermented once the yeast has eaten all the available sugars and starts consuming the gluten. This, alongside lactic acid bacteria also breaking down the gluten, weakens the dough structure. The dough is then likely to collapse, although this doesn’t always happen. A weak, uneven crumb structure is typical when bread has been over-proofed. The pungent smell of alcohol may remain in the bread after baking. You can also find that the bread is very pale due to it being over-oxidised.

Ending thoughts on the bulk fermentation

Bulk fermentation is a complicated subject, and there are endless thoughts, commenters and experiments available that aim to help, yet (if you don’t know the basics) often make the subject more complicated than it is. It’s impossible to create a bulk fermentation guide where every reader will want to read every word!

I hope by reading this, you will have a better understanding of the process and how you can improve your bread by mastering bulk fermentation. I’ll leave you with some frequently asked questions that I couldn’t fit in without ruining the flow of the article!

Bulk fermentation frequently asked questions

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