Book Reviews, Bread, Cooking Knowledge, Non Recipes

What is autolysis in breadmaking and is it worth the extra effort?

0 comments

In breadmaking, dough autolysis refers to mixing flour and water followed by a rest period. After the resting phase, the other dough ingredients are added and the dough is mixed and kneaded. Autolysis reduces the required mixing time until the dough is fully developed and, thereby, reduces the dough’s oxidation level. A high level of dough oxidation because of intense kneading is associated with a loss of aromatic flavor compounds and color pigments (carotenoids) in bread.

The term autolysis was first used by the French professor Raymond Calvel who claims to be the inventor of the technique. It’s doubtful that, in 1974, he was the first person in this world that had the idea to let bread dough rest before kneading it. But credit goes to him for describing and investing the effects of autolysis on bread dough.

Calvel’s experiments were driven by his desire to improve the taste of French bread. In his eyes, the quality of bread had declined in the post World War II years because of new flour and dough conditioners, intense kneading processes, and shortened fermentation times.

It’s not easy to find primary literature that investigates the effects of autolysis on bread dough. Raymond Calvel’s book “The taste of bread” provides an insight into his theories and thoughts. However, the book only scratches the surface when it comes to the science and answering the why questions. It is written for a general audience rather than experts.

The taste of bread book by Raymond Calvel - the book that introduces autolysis

In the first part of this discussion, I will introduce you to Calvel’s ideas and take a look at primary literature to see if I can confirm his theories and claims. And then I will answer you if, when, and how to implement autolysis into your breadmaking process.

Benefits of autolysis (What does autolysis do?)

Benefits of autolysis according to Raymond Calvel

The advantage of dough autolysis according to Calvel is that the dough mixing time gets reduced by approximately 15 % which lowers the dough’s oxidation level. As a result of the shortened mixing time, the bread is more flavorful, has more volume, better cell structure, and a more supple crumb.

The secret to great-tasting bread according to Clavel is simple:

  • During mixing, the dough should not be oxidized or denatured so that it retains the authentic flavor of wheat flour.
  • The addition of Baker’s yeast should be kept to a minimum so that the first rise of the dough extends over more than 4 hours.

Clavel’s book The Taste of Bread is not a book about autolysis and its effects. It’s a book that criticizes modern bread production processes where a full loaf of bread is produced in less than 2 hours. Autolysis is a method suggested by Clavel to decrease the gluten development time, and thus the level of dough oxidation, during mixing.

The impact of dough oxidation on bread

Before World War II, doughs were easy to mix and develop because of the low protein content and poor protein quality of old wheat cultivars compared to modern cultivars. Because of their stronger gluten, newer wheat cultivars require a longer and more intense kneading process until they are fully developed. Thus after World War II, high-speed dough mixers became commonplace in artisanal and industrial bakeries.

Dough industrial mixer

While kneading bread dough, we not only develop the gluten network but also aerate it. Aeration of bread dough brings with it the incorporation of atmospheric oxygen. Oxygen causes some of the dough components like gluten proteins or lipids to become oxidized. The more intense and longer the kneading process, and the higher the dough temperature, the higher the level of dough oxidation.

Within limits, oxidation has the short-term effects of increasing the strength of the dough, hastening its physical development, and reducing the length of time necessary for maturation of the dough. Excessive oxidation causes bleaching and deteriorates the taste of bread.

Whenever the mechanical energy input during mixing is low, this needs to be made up for by an increased fermentation time (maturation period). If you’ve ever baked a no-knead bread then you have experienced this phenomenon first hand. No-knead bread works because an extended fermentation time with a few stretch and folds in between can achieve similar results to kneading bread dough.

Modern high-speed mixers, as used by professional bakeries and the food industry, can develop a dough made from strong wheat flour in less than five minutes. Under these conditions, the contact of atmospheric oxygen with the dough is reduced because of the limited air exposure time. The food industry solves this problem by the addition of oxidizing additives like bean flour, ascorbic acid, or enzyme preparations.

These additives cause an artificial dough maturation that, combined with the intense mixing, goes hand in hand with excessive and uncontrolled dough oxidation. The need for a primary bulk fermentation (first rise) gets shortened to a minimum or is not even required as in the Chorleywood bread process. In the Chorleywood process, the dough can be molded and proofed directly after kneading. This is great for the food industry, but no so great for the flavor of the bread.

The impact of bean flour on bread dough

Soybeans
Bean flour is produced from dried and milled fava or soybeans.

Cavel has a strong aversion against one particular oxidizing additive: bean flour. Bean flour is a popular additive in France, especially in baguette flour, because it is a processing aid that improves the bread volume. It contains lipid-cleaving enzymes (lipoxygenases). Lipoxygenases oxidize the lipids naturally present in flour. Some of the lipid oxidation products, together with the emulsifiers (lecithin) in bean flour, act on the gluten to improve the strength and stability of the gluten network.

Adding to that, bean flour has a whitening effect on bread dough. Today, it is seen as a sign of superior quality among gourmets if the crumb of baguettes has a light yellow-orange hue. But many consumers prefer their bread to be perfectly white.

This preference is not as widespread in Europe as it is in other parts of the world like Asia, South America, and North America. Bleaching flour with chemicals has been forbidden in Germany since 1958. Of course, this ban is only valid for strong bleaching agents such as chlorides, bromates, and peroxides. Bean flour is not illegal in the EU but artisanal bakers usually don’t add it to bread dough because of its bleaching effect but because of its gluten strengthening effects.

The yellow color of bread dough is caused by the carotenoids in wheat flour. French baguette flour (Type 65) of the highest quality is rich in carotenoids. If we bring these carotenoids in contact with atmospheric oxygen and lipoxygenase enzymes, they get oxidized and their color diminishes.

French baguettes with yellow crumb
The crumb of a traditional French baguette is supposed to be yellow.
Chinese steamed bread
An important characteristic of many Asian bakery goods is that they are white like snow. Thus flour bleaching is common in these countries.

It is important to note that not just bean flour contains lipoxygenases. Lipoxygenases are also naturally present in wheat flour, albeit at a much lower level. Even if you don’t add bean flour to your baguette dough, then it is still beneficial to autolyse the dough and to only knead it gently if you want to end up with the most beautiful yellow cream-colored crumb.

To conclude: lipoxygenases are not evil as stated by Clavel! Besides their whitening effect, which is undesirable in French baguettes, they increase the gluten strength and thus help bakers to achieve a more open crumb.

Does autolysis have an impact on the flavor of bread?

Yes, autolysis has a minor impact on the flavor of bread because of the shorter mixing time and lower oxygen inclusion during kneading. However, this impact is subtle. Fermentation time and temperature have a far bigger influence on the bread flavor.

Clavel claims that the mixing intensity and dough oxidation level have an impact on the average levels of volatile organic acids in the bread crumb. Volatile organic acids are flavor compounds. The level of isobutyric and isovaleric acids is about 3.5 times higher in straight doughs that have been mixed intensively than in slowly mixed doughs. Adding to that, the flavor of intensely mixed bread is mostly dominated by acetic acid.

The aroma of iso-acids is considered by many consumers to be unpleasant because they are foul-smelling. Acetic acid tastes one-dimensional like vinegar and doesn’t have much depth of flavor.

During the mixing stage of bread dough, substrates for the generation of volatile flavor compounds are formed due to an increase in the rate of enzymatic reactions and lipid oxidation. Lipid oxidation leads to the formation of short-chain fatty acids that have a rancid taste. Responsible for speeding up these reactions is the oxygen that is incorporated into the dough during mixing.

Mixing a shaggy bread dough for autolysis

Intensely mixed dough possesses a greater maturity level after mixing and thus requires a shorter bulk fermentation. However, the first few hours of bread dough fermentation are characterized mainly by an increase of iso-alcohols whereas other, more complex flavor compounds, get formed 5 hours and later into fermentation.

To conclude: It makes more sense to reduce the amount of yeast added to bread dough and to elongate fermentation times to improve its flavor than to solely rely on short and gentle mixing to minimize the formation of off-flavor compounds.

Does autolysis increase the loaf volume?

Autolysis might have a minor positive effect on the volume of the baked loaf if it is combined with gentle mixing of the dough. However, at most, this is a minor effect and no argument that by itself would justify leaving the dough to rest before kneading.

The most important factors influencing the loaf volume are:

  • The quantity and quality of the gluten
  • The skill of the baker

If autolysis increases the loaf volume, then it would be reasonable to assume that it has an impact on the gluten structure. And indeed, we can see that the dough has gained structure and that the gluten network gets partially developed during autolysis.

When we mix flour with water, then we can observe two water phases. Most of the water in bread dough is “bound” water that hydrates the proteins and is absorbed by the starch granules. The second coexisting water phase in bread dough is called the “free” water phase. The continuous free water phase serves as the medium for chemical reactions occurring during dough development and fermentation.

The gluten proteins start to form a network as soon as the flour gets hydrated. You know this from making pancakes. People will often tell you to not overmix the batter so that the pancakes don’t turn out chewy.

If you prepare pancake batter with buckwheat flour instead of wheat flour then you will notice that the pancake batter will behave very differently. It won’t hold together as well. Buckwheat pancakes are not stretchable. They tear easily. Even if you just briefly combine all your pancake ingredients without mixing the batter for an extended amount of time, a batter made from wheat flour will form a weak gluten network that will lend the batter its elasticity and extensibility.

Buckwheat pancakes
German Buckwheat pancakes

At the early stages of dough development, the gluten proteins are present in the form of lumps, with little interconnectivity. The mixing process in breadmaking aims to quickly develop the gluten network by rearranging the bonds between the gluten subunits. When we knead bread dough, we constantly break and form new disulfide bonds. The strength of the formed network increases until it is optimally developed.

The flour in a dough that has been autolysed is already fully hydrated before mixing begins. Just by hydrating wheat flour, we already develop a weak gluten network with little interconnectivity. Therefore, the required mechanical energy input until the gluten network is fully developed is reduced for doughs that have been autolysed.

There is scientific evidence that a decreased mixing speed (energy input) during kneading increases the dough stability whereas high-speed mixing increases the dough consistency. The dough viscosity of intensely mixed doughs is believed to be increased because starch granules get ruptured by the high mechanical energy input. Damaged starch granules can bind more water than native starch granules. Thus, a larger percentage of damaged starch granules makes the dough firmer.

What’s the role of enzymes during autolysis?

A lot of internet blogs will tell you that the term autolysis is derived from the Greek words αὐτο- (“self”) and λύσις (“splitting”). In biology, autolysis refers to the breakdown of cells by their own enzymes. So does autolysis in bread dough refer to the break down of flour by its own enzymes?

I don’t think so. Three types of enzymes are of great importance when it comes to breadmaking:

  • Amylases that break down starch molecules
  • Lipases that break down lipids (fats)
  • Proteases that break down proteins

When we hydrate flour then we activate/ increase the activity of these enzymes. Free water is required so that enzymes can catalyze reactions. This means that enzymatic reactions are happening during autolysis.

The big question is: To what extent do these reactions have an impact on bread dough? After mixing of bread dough, the enzymes are still active. Why should it make a difference if we leave the flour to hydrate for 30 minutes before mixing? The enzymes are active throughout the entire breadmaking process from hydrating the dough until they become inactivated in the hot oven.

There is no scholastic research that proves that the enzyme activity during autolysis has any special impact on bread dough. Of course, if you autolyse your dough for several hours or even overnight, then you will notice something the next day: the dough will be softer. This is because the proteolytic enzymes naturally occurring in flour will have broken down some of the gluten proteins. But you can also experience this phenomenon if you prepare a simple pre-ferment or leave your final dough to rise for a long time.

In most cases, bread dough is left to autolyse for 20-30 minutes. The goal is to hydrate the flour to decrease the required mixing time. Unless proven otherwise by scientific research, we should assume that these 20-30 minutes of enzyme activity have no major or unique impact on bread dough. If you have any convincing arguments based on scientific research that prove me wrong, then drop them in the comments or send me a message.

Why is autolysis done without salt?

Himalaya pink salt

Most people will insist that salt needs to be added after autolysis of the dough. While it is beneficial to add salt after autolysis, it is no requirement. The flour will hydrate no matter if salt was added to the dough prior to autolysis.

Salt delays the gluten network formation because it is believed by scientists to delay gluten hydration. The presence of salt (sodium chloride) could reduce the surface charge of gluten proteins and thus lessen their ability to interact with water molecules. As discussed earlier, the hydration of gluten proteins is a prerequisite for protein network formation.

While salt delays the gluten hydration and thus increases the dough development time, it also increases the gluten strength. Salt impacts the protein unfolding and alignment of the gluten proteins. Salt encourages the formation of a fibrous gluten network from elongated protein strands.

A common technique to reduce the kneading time, besides autolysis, is to knead the dough without the addition of salt first. Calvel is strictly against this procedure as he claims that the oxidation of dough is lessened upon the addition of salt to bread dough. However, Calvel doesn’t back up this claim in his book.

Scientific studies indicate that the addition of salt can cause either antioxidative or oxidative action. One particular study by Japanese researchers even concluded that the addition of 2 % salt, as is common in bread dough, increases the lipid oxidation rate. For salt to have an antioxidative effect on bread dough, the salt concentration should be 8 % or higher which is not realistic!

I can’t recommend you to follow Cavel’s advice here. If you don’t have time to autolyse your dough and want to reduce the kneading time, then hold back the salt until the dough is almost fully developed. This has no negative impact that I am aware of and that is scientifically proven.

As for the autolysis: It will take longer for the gluten proteins to hydrate if you add salt to the autolyse dough. That might make a small difference if you autolyse your dough for 20 minutes or less. However, there is no scientific research that supports the claim that salt in concentrations of 2 % or lower inhibits the enzyme activity in bread dough.

Salt increases the osmotic pressure in bread dough and thus it slows down the yeast metabolism. Adding to that, salt competes with the other dough ingredients for water and thus reduces the availability of free water in the dough. As autolysis is generally recommended for high-hydration doughs it seems unlikely to me that the water activity (a measure for the amount of free water) gets reduced far enough by salt to slow down the enzyme activity. The water activity of freshly baked bread is typically 0.95 or higher. And this is after all the water loss in the oven during baking!

Safety by Control of Water Activity: Drying, Smoking, and Salt or Sugar  Addition - The water activity diagram - ScienceDirect
The water activity of bread dough is typically higher than 95 % so that the enzyme activity isn’t inhibited by a lack of free water. Picture Source: Science Direct

When and how to incorporate autolysis into your breadmaking process

When to autolyse?

Autolysis is recommended for high-hydration doughs because they require a longer mixing time than doughs with lower hydration levels. I apply an autolysis step only for doughs with hydration levels higher than 65 %. Anything below that can easily be kneaded directly either by machine or by hand without excessively oxidizing the dough.

I don’t use industrial high-speed dough mixers at home. I use primitive equipment for home bakers, often just my hands. Especially when kneading by hand, I am very thankful for the reduced kneading time requirements of autolysed dough. And with my simple equipment, there is no risk of over-oxidizing the dough.

Mixing bread dough by hand for autolysis

The effects of autolysis are subtle and other methods can also help to shorten the mixing time which I think Cavel criticizes for no good reason in his book:

  • Delayed addition of salt during kneading
  • Kneading a dough with medium hydration until almost fully developed before adding more water to soften the dough consistency (“bassinage”)

Autolysis is a nice technique to incorporate into your breadmaking routine but it is not the holy grail of baking. Autolysis can’t do any wonders and it won’t probably transform the way you bake bread. By looking at the recipes posted on other baking blogs, I can see that autolysis is very popular especially among American bakers.

It’s a technique that, in my opinion, is over-glorified and overused. Doing autolysis won’t do any harm to your bread. But if an autolysis step has no or only minimal impact on the baked loaf, then why bother doing it? Autolysis for baguettes and ciabatta: yes. Autolysis for a simple country bread or bread rolls with moderate hydration: no.

How long to autolyse dough?

If your sole intention is to hydrate the flour before mixing then 20-30 minutes of autolysis are enough. If you’re working with a very coarse whole grain flour, then you might want to extend that period a little as fiber particles have a dehydrating effect on the gluten proteins.

The water in bread dough gets constantly redistributed, especially during mixing. The water retention capacity of the fibers is much larger than the one of gluten and starch. This leads to an unfavorable redistribution of water between dough components. Gluten and starch are partially dehydrated because the fibers beat them in the competition for water. This results in a deterioration of the dough consistency. Pre-hydrating the fibers by an autolysis step has a positive impact on the gluten network formation during mixing.

If you not only want to hydrate the flour but also soften it, then an extended autolyse for several hours, or even overnight, makes sense. This gives the proteolytic enzymes in the flour time to get to work and cleave gluten molecules into smaller fragments. Especially if you’re doing an overnight autolyse, I urge you to do it in the fridge. Lower temperatures slow down the enzyme reaction rate. If you overdo it with the gluten softening, then your dough will have little stability, be stickier, and result in a loaf with a smaller volume.

Soft dough because of an extended autolysis

Besides the proteolytic enzymes, the amylases can also get to work during an extended autolyse. These enzymes cleave starch molecules into smaller sugar subunits that serve as food for the yeast. If there is more food for the yeast in the dough, then the dough rises quicker.

Lipases are also activated upon hydrating flour. They can modify the structure of phospholipids which are naturally present in wheat flour to improve their ability to act as an emulsifier. Emulsifiers can bind to gluten proteins. If they bind to gluten proteins, they help to stabilize gas bubbles within the dough.

However, the enzymatic effects of an extended autolyse can also be achieved by working with pre-ferments. The enzymes will also do their job in a sourdough that you feed the day before baking. As a general rule of thumb: if the dough contains no pre-ferments, then an extended autolyse can be beneficial. If you’re working with sourdough or yeasted pre-ferments, then there’s hardly any benefit from leaving your final dough to autolyse for more than 20 minutes.

Resources and further reading

The Taste of Bread

Dynamics of Volatile Compounds in Triticale Bread with Sourdough: From Flour to Bread

Volatile compound and organic acid productions by mixed wheat sourdough starters: influence of fermentation parameters and dynamics during baking

The Impact of Water Content and Mixing Time on the Linear and Non-Linear Rheology of Wheat Flour Dough

Studying of mixing speed and temperature impacts on rheological properties of wheat flour dough using Mixolab

Effect of sodium chloride on gluten network formation, dough microstructure and rheology in relation to breadmaking

Effects of Salt on Wheat Flour Dough Fermentation

Bread Dough and Baker’s Yeast: An Uplifting Synergy

The effect of sourdough and calcium propionate on the microbial shelf-life of salt reduced bread

Water redistribution between model bread dough components during mixing

Leave a Comment

Your email address will not be published.