Stretch folds (#35)

* Remove whitespaces

* Add troubleshooting section starter size increase

* Finish stretch and fold chapter

book/references.bib

@@ -298,4 +298,12 @@
   howpublished = {\url{https://bread.blog/enzymes-and-ph-matter-troubleshoot-my-loaf/}},
   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
@@ -316,4 +317,4 @@ I would achieve less oven spring.
 Generally though achieving too much steam is relatively challenging. I could only
 commit this mistake when using a dutch oven as steaming method paired with relatively
 large ice cubes. After talking with other bakers using the same dutch oven, it seems
-that mine (around 80g) were 4 times as heavy as the ones other bakers would use (20g)
+that mine (around 80g) were 4 times as heavy as the ones other bakers would use (20g)

book/troubleshooting/misc.tex

@@ -492,5 +492,61 @@ potential pathogens. The acidic environment is toxic
 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 
+sourdough starter into a stiff starter as
-described in section \ref{section:stiff-starter}.
+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

@@ -26,7 +26,7 @@ found another valuable puzzle piece. Aggregating all this
 information was one of my main motivations to start the bread code.
 My key learning was that there there is no recipe that
 you can blindly follow. You will always have to adapt the recipe
-to your locally available tools and environment. 
+to your locally available tools and environment.
 
 But do not worry. After reading this chapter you will know
 all the signs to look out for. You will be able to read your dough.
@@ -44,16 +44,16 @@ that tastes much better than any store-bought bread.
 
 \begin{figure}[!htb]
   \begin{tikzpicture}[node distance = 3cm, auto]
-    \node [block] (init) {\footnotesize Ready starter}; 
+    \node [block] (init) {\footnotesize Ready starter};
-    \node [block, right of=init, node distance=3cm] (mix_ingredients) {\footnotesize Mix ingredients}; 
+    \node [block, right of=init, node distance=3cm] (mix_ingredients) {\footnotesize Mix ingredients};
-    \node [block, right of=mix_ingredients, node distance=3cm] (dough_strength) {\footnotesize Create dough strength}; 
+    \node [block, right of=mix_ingredients, node distance=3cm] (dough_strength) {\footnotesize Create dough strength};
-    \node [block, right of=dough_strength, node distance=3cm] (bulk) {\footnotesize Bulk ferment}; 
+    \node [block, right of=dough_strength, node distance=3cm] (bulk) {\footnotesize Bulk ferment};
     \node [decision, below of=dough_strength, node distance=3cm] (divide_test) {\footnotesize Making 1 loaf?};
-    \node [block, left of=divide_test, node distance=3cm] (divide) {\footnotesize Divide}; 
+    \node [block, left of=divide_test, node distance=3cm] (divide) {\footnotesize Divide};
-    \node [block, left of=divide, node distance=3cm] (preshape) {\footnotesize Preshape}; 
+    \node [block, left of=divide, node distance=3cm] (preshape) {\footnotesize Preshape};
-    \node [block, below of=preshape, node distance=3cm] (shape) {\footnotesize Shape}; 
+    \node [block, below of=preshape, node distance=3cm] (shape) {\footnotesize Shape};
-    \node [block, right of=shape, node distance=3cm] (proof) {\footnotesize Proof}; 
+    \node [block, right of=shape, node distance=3cm] (proof) {\footnotesize Proof};
-    \node [block, right of=proof, node distance=3cm] (bake) {\footnotesize Bake}; 
+    \node [block, right of=proof, node distance=3cm] (bake) {\footnotesize Bake};
     \path [line] (init) -- (mix_ingredients);
     \path [line] (mix_ingredients) -- (dough_strength);
     \path [line] (dough_strength) -- (bulk);
@@ -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.
@@ -118,21 +119,21 @@ main dough.
   \begin{tikzpicture}[node distance = 3cm, auto]
     \node [decision] (init) {\footnotesize Starter last fed within 3 days?};
     \node [block, right of=init, node distance=4cm] (feed_no_branch)
-      {\footnotesize Feed starter twice. 48 hours before and 6-12 hours before}; 
+      {\footnotesize Feed starter twice. 48 hours before and 6-12 hours before};
     \node [block, below of=feed_no_branch, node distance=3cm] (feed_yes_branch)
-      {\footnotesize Feed starter once 6-12 hours before making dough}; 
+      {\footnotesize Feed starter once 6-12 hours before making dough};
     \node [block, right of=feed_no_branch, node distance=6cm] (high_ratio)
-      {\footnotesize Use a 1:10:10 ratio. 10g starter, 100g flour, 100g water}; 
+      {\footnotesize Use a 1:10:10 ratio. 10g starter, 100g flour, 100g water};
     \node [block, right of=feed_yes_branch, node distance=3cm] (low_ratio)
-      {\footnotesize Use a 1:5:5 ratio. 10g starter, 50g flour, 50g water}; 
+      {\footnotesize Use a 1:5:5 ratio. 10g starter, 50g flour, 50g water};
     \node [block, below of=high_ratio, node distance=6cm] (check_starter)
-      {\footnotesize Check if starter is ready to be used}; 
+      {\footnotesize Check if starter is ready to be used};
     \node [decision, below of=init, node distance=6cm] (size_check)
       {\footnotesize Bubbly? Increased in size?};
     \node [decision, below of=size_check, node distance=5cm] (smell_check)
       {\footnotesize Vinegary or yogurty smell?};
     \node [block, right of=smell_check, node distance=6cm] (make_dough)
-      {\footnotesize Prepare dough}; 
+      {\footnotesize Prepare dough};
     \path [line] (init) -- node{no} (feed_no_branch);
     \path [line] (init) -- node{yes} (feed_yes_branch);
     \path [line] (feed_yes_branch) -- (low_ratio);
@@ -342,7 +343,7 @@ is however one option that makes things easier and causes fewer headaches:
 Slow fermentation. You get the same extensibility advantages the high hydration
 offers by simply letting your dough ferment for a longer period.
 Slowing the fermentation process is easy. Use less
-sourdough starter or ferment in a cooler environment. 
+sourdough starter or ferment in a cooler environment.
 
 There are two reasons for the slow fermentation advantages.
 As explained earlier both the protease enzyme and bacteria break down your
@@ -388,7 +389,7 @@ If you are just getting started with a new batch of flour
 I recommend conducting the following test. This will help you to
 identify the sweet spot of your flour's hydration capabilities.
 
-Make 5 bowls with each 100g of flour. Add different slightly increasing 
+Make 5 bowls with each 100g of flour. Add different slightly increasing
 water amounts to each of the bowls.
 
 \begin{itemize}
@@ -401,7 +402,7 @@ water amounts to each of the bowls.
 
 Proceed and mix the flour and water mixture until you see that there
 are no chunks of flour left. Wait 15 minutes and return to your dough.
-Carefully pull the dough apart with your hands. Your dough should be elastic, holding 
+Carefully pull the dough apart with your hands. Your dough should be elastic, holding
 together very well. Stretch your dough until very thin. Then hold it against a light.
 You should be able to see through it. The flour water mixture that breaks without
 seeing the windowpane is your no-go zone. Opt for a dough with
@@ -595,7 +596,7 @@ the gases would just diffuse out of your dough.
 
 \begin{figure}[!htb]
   \begin{tikzpicture}[node distance = 3cm, auto]
-    \node [block] (init) {\footnotesize Homogenize recipe ingredients}; 
+    \node [block] (init) {\footnotesize Homogenize recipe ingredients};
     \node [block, right of=init, node distance=3cm] (wait1) {\footnotesize Wait 15 minutes};
     \path [line] (init) -- (wait1);
     \node [block, right of=wait1, node distance=3cm] (knead1) {\footnotesize Knead 5 minutes};
@@ -685,7 +686,7 @@ After waiting to allow the flour to soak up the water, proceed on a higher speed
 setting. A good sign of a well-developed gluten network is
 that your dough lets go of the container. This is because of the gluten's elasticity.
 The elasticity is higher than the urge of the
-dough to stick to the container. 
+dough to stick to the container.
 
 \begin{figure}[!htb]
   \includegraphics[width=\textwidth]{dough-strength-sourdough}
@@ -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
@@ -766,7 +768,7 @@ has a nice smooth surface. The final dough should look like the dough
 shown in \ref{fig:dough-ball-steps}.
 
 If your outer gluten layer tears you have overstretched your dough. In
-that case, take a 10-minute break leaving your dough on the kitchen countertop. 
+that case, take a 10-minute break leaving your dough on the kitchen countertop.
 This allows the gluten to re-bond and heal. Repeat the same process
 and the damaged rugged areas should disappear.
 
@@ -805,7 +807,7 @@ The key is to find the sweet spot between not too little
 and not too much bulk fermentation. I'd always recommend pushing
 the dough more toward a longer fermentation. The
 flavor of the resulting bread is better compared to a pale
-underfermented dough. 
+underfermented dough.
 
 \begin{table}[!htb]
   \small
@@ -821,7 +823,7 @@ underfermented dough.
   \caption{The different stages of sourdough fermentation and the effects on crumb, alveoli, texture, and overall taste.}
 \end{table}
 
-The worst thing you can do when fermenting sourdough 
+The worst thing you can do when fermenting sourdough
 is to rely on a recipe's timing suggestions. In 99 percent
 of the cases, the timing will not work for you. The writer
 of the recipe probably has different flour and a different
@@ -842,7 +844,7 @@ Experienced bakers will tell you to go by the look and feel of
 the dough. While this works if you have made hundreds of loaves,
 this is not an option for an inexperienced baker. As
 you make more and more dough you will be able to judge
-the dough's state by touching it. 
+the dough's state by touching it.
 
 My go-to method for beginners is to use an \textbf{Aliquot jar}.
 The aliquot is a sample that you extract from your dough. The
@@ -973,7 +975,7 @@ While this method is very reliable there are also certain
 limitations to consider.
 
 First of all the pH values that work for me likely won't work for
-you. Depending on your own starter's composition of lactic 
+you. Depending on your own starter's composition of lactic
 and acetic acid bacteria your pH values will be different.
 You can use the values shown in table \ref{table:sample-ph-values}
 as rough ballpark figures. Regardless you need to find values
@@ -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}