Stretch folds (#35)

* Remove whitespaces

* Add troubleshooting section starter size increase

* Finish stretch and fold chapter

book/references.bib

@@ -299,3 +299,11 @@
   year         = {2022},
   note         = {Accessed: 2022-12-28}
 } 
+
+@article{stretch+and+fold+technique,
+  title        = {How And When To Stretch And Fold Your Sourdough},
+  author       = {The Bread Code YouTube},
+  howpublished = {\url{https://www.youtube.com/watch?v=gMbZeUIVzZY}},
+  year         = {2022},
+  note         = {Accessed: 2023-01-06}
+} 

book/troubleshooting/crumb-structures/crumb-structures.tex

@@ -1,4 +1,5 @@
 \section{Debugging your crumb structure}
+\label{section:debugging-crumb-strucuture}
 
 The crumb structure of your bread provides insights on how well
 your fermentation process has gone. You can also spot common flaws

book/troubleshooting/misc.tex

@@ -494,3 +494,59 @@ to most pathogens that you do not want in your starter.
 Another approach that can help is to convert your
 sourdough starter into a stiff starter as
 described in section \ref{section:stiff-starter}.
+
+\section{My starter does not double in size}
+
+Some bakers call for the sourdough starter to
+double in size before using it.
+The idea is to use the sourdough starter at
+peak performance to ensure a
+balanced fermentation in the main dough.
+
+The doubling in size metric should be
+taken with a grain of salt when judging
+your starter. Depending on the flour
+you use to feed the starter different levels
+of its rising can be expected.
+For instance, if you use rye flour then only
+very little gas from the
+fermentation can be retained inside the
+starter. In consequence, your
+sourdough starter will not rise as much. It
+could be in a healthy shape
+though. If you use wheat flour with less gluten
+the starter will not rise as
+much too. The reason is that you have a weaker
+gluten network resulting in
+more gas dispersing out of your dough.
+
+That being said it is recommended that you develop
+your volume increase
+metric. Your starter will increase in size and then
+ultimately lose structure
+and collapse. Observe the point before it collapses.
+This is the point when
+you should use your starter. This could be a
+50 percent volume increase, 100
+percent or 200 percent. It is always better to use
+the starter a little bit
+too early rather than too late. If you use the
+starter later reduce the
+quantity that you use. If the recipe calls for a 20
+percent starter quantity,
+use only 10
+percent starter in that case. Your starter will
+regrow in your main dough.
+
+On top of relying on the size increase start
+taking note of your starter's
+smell. Over time you will be able to judge its
+fermentation state based on the
+smell. The stronger the smell becomes the further
+your dough has fermented.
+This is a sign that you should use fewer starters
+when making the actual dough.
+
+Please refer to section \ref{section:readying-starter} "\nameref{section:readying-starter}"
+for more information on the topic.
+

book/wheat-sourdough/wheat-sourdough.tex

@@ -105,6 +105,7 @@ All the steps rely on each other. You will need to get each of
 the steps right to make the perfect bread.
 
 \section{Readying your starter}
+\label{section:readying-starter}
 
 The most crucial part of the bread-making process is your starter.
 The starter is what starts the fermentation in your main dough.
@@ -694,6 +695,7 @@ dough to stick to the container.
   A combination of techniques can be utilized to achieve maximum
   dough strength.
   }
+  \label{fig:dough-strength-sourdough}
 \end{figure}
 % See https://www.figma.com/file/wTUVe6Nm2INOvT82mJhQur/Dough-strength-visualisation?node-id=0%3A1&t=fjdPvXYuJpsdQfWN-1 for
 % the source of this visualization
@@ -1053,9 +1055,122 @@ bread would feature an excellent very tangy taste.
 
 
 \section{Stretch and folds}
-This chapter is still pending and will be added soon.
 
-\section{Optional Preshaping}
+\begin{figure}[!htb]
+  \includegraphics[width=\textwidth]{dough-being-glued}
+  \caption{A dough where two sticky sides are being glued together using
+  a stretch and fold. This process creates excellent dough strength.}
+\end{figure}
+
+In this section, you will learn all you need to know about stretching and
+folding. You will learn when to stretch and fold and how to use this technique
+to your advantage.
+
+Stretching and folding is a set of techniques used by bakers during the bulk
+fermentation stage. The process involves stretching the dough and then
+folding the dough onto itself. Some recipes call for a single stretch
+and fold, others for multiple.
+
+The primary goal of this technique is to provide
+additional dough strength to your dough. As shown in figure \ref{fig:dough-strength-sourdough}
+there are multiple ways to create dough strength. \footnote{In fact I have seen many no-knead
+recipes calling for no initial kneading, but then applying stretch and folds
+during the bulk fermentation. The time required to do all the folds probably
+matches the initial kneading time required.} If you do not knead as much at
+the start you can reach the same level of dough strength by applying stretch
+and folds later. The more stretch and folds you do, the more dough strength
+you add to your dough. The result will be a more aesthetic loaf that has
+increased vertical oven spring.
+
+Sometimes if the dough is very extensible,
+and features very high hydration, stretching and folding is essential.
+Without it, the dough itself would have too little dough strength and not
+spring in the oven at all.
+
+Another benefit of stretch and folds are their homogenization properties. By
+folding the dough you are redistributing areas that are fermenting faster
+than other areas. The heat in your dough is not the same in all areas.
+The fermentation itself produces heat. For that reason, some of the areas in
+your dough will ferment a little faster than others. This means that some
+areas hold more gas and more acidity than others. Applying a stretch and fold
+will redistribute heat, gas, and acidity. Some bakers also refer to this
+process as crumb building. Careful folds ensure that your final dough's crumb
+is not overly wild featuring large cavities. If you notice overly
+large areas in your final dough's crumb, then you might be able to fix that
+by applying more stretch and folds.\footnote{In many cases these cavities can
+also happen when a dough does not ferment enough. The crumb is commonly called
+Fool's Crumb. Refer to the later debugging crumb structures chapter of this
+book to learn more about it.} Please refer to section \ref{section:debugging-crumb-strucuture}
+"\nameref{section:debugging-crumb-strucuture}" for more information on reading
+your crumb.
+
+\begin{figure}[!htb]
+  \includegraphics[width=\textwidth]{stretch-and-fold-steps}
+  \caption{An overview of the steps involved to perform stretch and folds
+  for wheat-based doughs.}
+  \label{figure:stretch-and-fold-steps}
+\end{figure}
+
+The reason for the technique's popularity lies in its efficiency. By stretching
+the dough outwards you increase your dough's surface area. You then fold the
+dough over, essentially gluing large areas of the dough together. Imagine a
+piece of paper on which you place the glue. Then you fold the paper. Large areas
+of the paper now stick together. Repeat the same process with more glue until
+you have created multiple layers of paper and glue. This is the same thing that
+happens to your dough. With only very few movements you have applied glue to your
+dough.
+
+To apply a stretch and fold first wet your hands with cold water. Watered hands
+work wonders in reducing the dough's tendency to stick to your hands. Proceed and
+carefully loosen the dough from the edges of your bulk container. Do this by
+carefully placing your hand at the edge of the dough and pushing your hand
+downwards on the container's walls. Once you reached the bottom drag the dough
+a little bit inwards. The dough should stay in place and not move back to the
+edge of your container. Try to be as swift as possible with this motion. The
+slower you are, the more dough will stick to your hands. Repeat the same process
+once all around your dough until the dough is free of your container's edges.
+Wet your hands one more time and then carefully lift one side of the dough with
+two hands placed in the center upwards. Make a fold in the center of the dough.
+The upper smooth side needs to be placed on the bottom of the container. By doing
+so you will be gluing together the two sticky bottom sides. The top smooth side should
+not be sticky in your hands, while the bottom rough surface should tend
+to stick to your hands.  Rotate the container
+and repeat the same thing from the other side. Rotate the container 90° degrees
+clockwise and then repeat the process once again. Rotate the container another 180° degrees clockwise
+and repeat the fold one last time. By doing so you have applied 4 folds in total. Your
+dough should now stay in place and resist flowing outwards.
+\footnote{Please also refer to \cite{stretch+and+fold+technique} for a video showing
+you how to best perform the technique.}
+
+In theory, there is no limit to how often you can stretch your fold. You could
+apply one every 15 minutes. If your dough has enough dough strength already,
+applying additional folds is just a waste of time.\footnote{You could do it just to better understand how the
+dough feels in your hands at different fermentation stages.} If you apply a
+large number of consecutive folds, the outer layer of gluten
+will tear. In that case, you just have to wait for at least 5-10 minutes until
+the gluten bonds heal and you can try again. When the gluten does not heal
+anymore, chances are you have pushed the fermentation for too long. Likely
+most of the gluten has broken down and you are already
+in the decay stage shown in figure \ref{fig:dough-strength-sourdough}.
+
+\begin{figure}[!htb]
+  \includegraphics[width=\textwidth]{dough-requiring-stretch-and-fold}
+  \caption{A dough during bulk fermentation that has flattened out. To improve
+  its dough strength a stretch and fold should be applied.}
+\end{figure}
+
+
+Now the reasonable amount of stretch and folds you should do greatly depends on how much you
+kneaded initially and how extensible your dough is. A good recommendation is
+to observe your dough in your bulk container. Once you see that the dough
+flattens out quite a lot and spreads towards the edges of your bulk container
+you can proceed and apply a stretch and fold. For 95 percent of the doughs
+that I am making this is hardly more than once. I like to make overnight
+doughs and in that case, I typically apply one stretch and fold directly after
+waking up. Then the bulk fermentation might take another 2 hours before I
+proceed with dividing and preshaping or directly shaping.
+
+\section{Optional: Dividing and Preshaping}
 This chapter is still pending and will be added soon.
 
 \section{Shaping}