The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Richard Bertinets Slap and Fold myths

Gratefulbread's picture
Gratefulbread

Richard Bertinets Slap and Fold myths

I have watched this method and I am a big fan, however I do not believe in the trapping air in the dough theory. I dont think your are actually trapping amounts of air in the structure of the dough. For one the dough would find a way to expel  the trapped air by natural compression (gravity). Two I think if air was being trapped it would reveal itself as a huge pocket in the finished product. Like I said I am a fan but I believe the description given by Richard in the video on sweet dough is misleading and well an impossibility.  Any thoughts ?

PiPs's picture
PiPs

Hi Gratefulbread,

Pretty much all of my breads are kneaded using a method similar to Richard's. I tend to pick the dough up sideways so I can get a better stretch and flick over. I have heard about the trapping air not just from Richard but from other french bakers and I believe there is something to it. Have you tried this method?

When I am kneading I can see and feel the point where the dough and gluten have developed nicely. And what I see are large airpockets trapped by a thin sheath of dough ... almost like a windowpane wrapped around the outside of the dough. When I rest it for a moment on the bench I can see air bubbles around the outside of the dough. These will most likely get redistributed and pressed down during stretch-and-folding.

Whether the trapped air contributes anything to the final bread I can't really say ... It's just a method that works well for well hydrated doughs.

Cheers,
Phil

mwilson's picture
mwilson

I too am a fan of this kneading method. I believe it's the stretch, the extension that you exert on the dough that's responsible for the actual kneading. But there is oxidation happening too. Typically after kneading there are noticeable air pockets under the surface of the dough. Oxygen does cause some form of chemical change to gluten. I'm sure someone more in the know can explain...

Any type of kneading will cause some degree of oxidation. Too much has negative effects; bleaching the flour's natural colour and destroying it flavour.

I have adapted this method and made it more specific.  I see it as proving a degree of extension.

Initially after an autolyse I work slowly slapping and stretching outward over itself allowing for some minimal tearing until the tearing stops. I then increase the slapping and stretching to a higher degree, again allowing for minimal tearing until smooth again. I continue like this until the dough wraps itself  tight and doesn't tear anymore. i.e. full gluten development. This is referred to maximum extension in my book "Cresci: The Art Of Leavened Dough" which makes sense.

 

In my mind it works like this:

Hydration allows gluten to develop.  Without water gluten doesn't exist.

Kneading, however you do it, aligns gluten.

The more aligned the gluten the more elastic and extensible the dough becomes.

ananda's picture
ananda

Hi Michael,

It might be better to try to differentiate between elasticity and extensibility when considering oxidation during mixing.

The hydrated proteins have to compete with other materials in the dough, as it mixes...principally the yeast, of course.

Oxidation allows for the development of a stronger gluten network in a process known as the disulphide interchange.   This simply means the formation of a sequence of cross-bonds interlinking the long gluten strands which form as you describe.   This is the elasticity to which you refer, and I often compare the gluten network to lycra as used in stretchy clothing.   So, when you stretch the dough, elasticity measures the propensity to spring back.

Extensibility comes later in the process, unless using industrial processes involving mixing energy, or, chemicals/enzymes.   We of course rely on fermentation, whether a long bulk ferment, or the use of a pre-ferment as a means to reduce the strength of the dough by weakening these cross bonds and creating extensibility.   This is what then allows the dough to stretch.   The combination of the 2 then allows the dough to expand and trap in the gas created by fermentation.

This appears to be different to some degree to what Cresci describes, but I'm just thinking that greater extensibility in dough is manifest once the dough has been allowed to relax for a short period of time, rather than after the most intense period of mixing, whatever the choice of method used.

Best wishes

Andy

mwilson's picture
mwilson

Hi Andy,

A highly aligned network does indeed increase extensibility. If you imagine the gluten network as a set of interlinked paperclips, each one allows the next to pass through the length of the clip before stopping. From one end of the chain to the other the collective stretch is a total of each clip. Now imagine this network where some of the clips are knotted. They don't stretch fully, thereby reducing the total extension. As I knead the dough it's these knots that cause the tearing and as I continue to work them out the chains become longer and more aligned leading to a dough increasingly difficult to tear. So the resulting dough is both more elastic and more extensible.

Fermentation helps gluten to align and I believe a fermented dough's more aligned and relaxed gluten network is the real reason for greater extensibility rather than a form of autolysis. Fermentation is typically used to increase strength not reduce it.

Michael

 

Doc.Dough's picture
Doc.Dough

I am in agreement that S&F does not capture air for all of the reasons expressed. Bread is a foam so the dynamics of froth hold forth. Folded froth is not more frothy, but it does have fewer large bubbles (because they are unstable). The magic of writing books is that the publisher and the editor are clueless with respect to the techncial claims made without substantiation by authors in good faith but who lack the expertise (or time or willingness) to construct and execute competent experiments to support their claims.

So what can we say with authority about the process of stretch and fold?  What does it do (develop gluten I think). And why does it work? And how would we propose to test that hypothesis?  Until somebody does that, and documents the results with data it is just a game of liars dice.

Gratefulbread's picture
Gratefulbread

Thank you. I knew I couldnt be the only one to really think this notion through.

 

ehanner's picture
ehanner

You all who dispel the notion that air is incorporated during Bertinet's "Slap and Fold" are forgetting the energy in the fold or more accurately the Flipping at the end. If done properly, the last thing you do is flip the dough up on itself adding a layer over the stretched section of dough. You can do it lazily or you can do it with snap. The latter will aid in adding aeration to the dough in my opinion. While it may become foam later, at the early stages, little air is present. Any time you quickly cover one rough surface with another, there are bound to be small amounts of air trapped between the two.

Eric

Doc.Dough's picture
Doc.Dough

First, dough rises from the CO2 produced as a byproduct of yeast fermentation of the sugars in the dough, not from any "air" incorporated through stretch and fold operations.  A simple demonstration of this is left as an exercise for the student.

Second, the total volume of the bubbles in bread dough grows from near zero at completion of mixing, to approximately one half of the total dough volume at the end of proofing. There seems to remain some disagreement over what fraction of the bubbles in yeast bread are simply expanded bubbles that were incorporated during the mixing and what fraction formed spontaneously from local supersaturation of the dough with CO2. Irrespective of the source of the initial bubbles, the volume growth rate should be roughly proportional to the surface area of a bubble.

There is no evidence that S&F contributes to increased dough volume; in fact because the process releases CO2 from some pre-existing bubbles, there is a legitimate question of whether it even makes up for the loss of volume through that mechanism.

A reasonable experiment might involve freezing pieces of dough at different points during fermentation, then sectioning them for microscopic examination and bubble counting. A sample taken in conjunction with a S&F could be analyzed to determine the number of bubbles per square cm of cross-sectional area. The surface area of the folded dough (created during the S&F) would have to introduce at least that density of bubbles in order to contribute in any significant way to total bubble count.

I have not done that experiment, but I can envision no mechanism that would achieve that level of bubble creation.  It is hard to imagine that a significant number of bubbles are created during the initial mix (by incorporation of ambient air). I would suggest an alternate hypothesis - that the initial bubbles result from dry flour particles being surrounded by liquid during mixing, trapping air in the dry voids which may then be expanded by diffusion of CO2.

Another experiment might be called for in which a batch of dough is mixed in a vacuum and the volume expansion compared with a control batch mixed at atmospheric pressure.  If a vacuum is inconvenient, then perhaps mixing in a 100% CO2 environment would be a reasonable alternative since the CO2 would be absorbed by the dough in short order given the sub-saturated state at time of mixing. Soaking the flour in a CO2 atmosphere prior to mixing would potentially reduce the volume of "air" available for bubble formation and thus reduce the size of the initial bubbles to below the critical diameter required for growth. (see http://www.sciencedirect.com/science/article/pii/S0960308598700999)

 

PiPs's picture
PiPs

hmmm ... a lot of what you wrote goes completely over the top of my head. Anyhow ...

The reference to S&F you are using .... is that "slap and fold" or stretch and fold"? I think of it as "Stretch and fold" ... just so we are on the same page.

Even though I find the keading method similar in movement to a Stretch-and-Fold (I think of this as a slower movement),  it is really quite different when put into play. As Eric mentioned there should be flick and release at the end as the dough folded over itself. This is a quick snappy movement and it does trap air in the dough. You can see the bubbles it in a piece of kneaded dough before bulk fermenting. Whether it contributes to a final loaf I really can't say (and I do agree with you here ... probably not) but its not the reason that I knead my bread this way.

Cheers,
Phil

Doc.Dough's picture
Doc.Dough

If you could post a photo showing what you are referring to as trapped air prior to bulk fermentation, perhaps I would have a better idea of what you are seeing.  Any bubbles prior to bulk fermentation would have to be air incorporated during the mixing process since there has been no time for CO2 to accumulate.

Doc.Dough's picture
Doc.Dough

Here is a close up of a cross-section sliced from a freshly kneaded piece of dough, digitally processed to maximize the available constrast.  The corner to corner dimension is about 1" and the existing bubbles (microscopic) are those present only from the initial mixing. The dark spots are inclusions and bits picked up off the kneading surface.

amolitor's picture
amolitor

Bread is indeed leavened with bubbles of CO2 from the organisms leavening it (or chemistry) but bubbles do not for form spontaneously. They need a seed of some sort to start from (this is the same phenomenon where pure water is reluctant to boil if undisturbed, for instance, in the microwave).

Air incorporated during kneading may provide very small seed bubbles which the CO2 can expand.

 

Mini Oven's picture
Mini Oven

to leaven it.  Tiny gluten pockets around melting snow flakes trapping tiny air pockets in the dough.  The "drier" the snow, the better.    :)

Mebake's picture
Mebake

Huh?

Mini Oven's picture
Mini Oven

Need more nearby snow...