History chapter (#3)

This adds the history chapter talking about the history of sourdough
bread.

book/book.tex

@@ -19,7 +19,12 @@
     allcolors=black
 }
 
-\graphicspath{ {./images/}{./troubleshooting/crumb-structures/}{./images/external/} }
+\graphicspath{
+  {./images/}
+  {./troubleshooting/crumb-structures/}
+  {./history/}
+  {./images/external/}
+}
 
 
 \title{%
@@ -57,9 +62,7 @@
 \mainmatter
 
 \chapter{The history of sourdough}
-\section{Sourdough bread in ancient times}
-\section{How modern bread is made}
-\section{Sourdough in modern times}
+\input{history/sourdough-history}
 
 \chapter{How sourdough works}
 \section{Enzymatic reactions}

book/history/sourdough-history.tex

@@ -0,0 +1,159 @@
+Sourdough has been made since ancient times. The exact origins
+of fermented bread is however unknown. One of the most ancient
+preserved sourdough breads has been excavated in Switzerland.
+However based on recent research some scientists speculate
+that sourdough bread has already been made 12000 BC in ancient
+Jordan \cite{jordan+bread}.
+
+\begin{figure}[h]
+  \includegraphics[width=\textwidth]{einkorn-crumb}
+  \caption{An ancient Einkorn flatbread. Note the denser crumb structure.}
+  \label{einkorn-crumb}
+\end{figure}
+
+Another popular story is that a lady in Egypt was making
+a bread dough close to the Nile river. The lady forgot the
+dough and returned a few days later. She would notice that
+the dough had increased in size and smelled funky. She decided
+to bake the dough anyways. She was rewarded with a much
+lighter softer better tasting bread dough. From that day
+on she continued to make bread this way.
+
+Little did the people back then know that tiny microorganisms
+were the reason they made better bread. It is not clear when
+people started using a bit of the dough from the previous
+day for the next batch of dough. But by doing so sourdough
+bread making was born. Wild yeast on the flour and in the air
+plus bacteria start to decompose the flour water mixture, also
+known as your dough. The yeast makes the dough fluffy and
+the bacteria primarily creates acidity. Both the different
+microorganisms work in a symbiotic relationship. Humans
+appreciated the enhanced airy structure and slight acidity
+of the dough. Furthermore the shelf life of such a bread
+was extended due to the increased acidity. 
+
+Quickly similar processes were discovered when brewing beer
+or making wine. A small tiny batch of the previous production
+would be used for the next production. This way humans created
+modern bread yeasts, wine yeasts and beer yeasts. Only in 1680
+the scientist Anton van Leeuwenhoek first microscoped yeast
+microorganisms. Over time with each bach the yeasts and bacteria
+would become better at consuming whatever they were thrown at.
+By feeding your sourdough starter you are selectively breeding
+microorganisms that are good at eating your flour. With
+each iteration your sourdough knows how to better ferment the flour
+at hand. This is also the reason why more mature sourdough starters sometimes
+tend to leaven doughs faster (source needed). It is crazy if you
+think about it. People have been using this process despite not
+knowing what was actually going on for thousands of years! The
+sourdough in itself is a symbiotic relationship. But the sourdough
+also adapted to humans and formed a symbiotic relationship with us.
+For food and water we are rewarded with delicious bread. In exchange
+we shelter and protect the sourdough. Spores from the starter
+are spread through aerial contamination or through insects like fruit flies.
+This allows the sourdough starter to spread its spores even
+further all around the world. 
+
+Brewers would start to experiment utilizing the muddy leftovers
+of the beer fermentation to start making doughs. They would notice
+that the resulting bread doughs were becoming fluffy and compared
+to the sourdough process would lack the acidity in the final product.
+A popular example is shown in a report from 1875. Eben Norton Horsford
+would write about famous "Kaiser Semmeln" (Emperor's bread rolls).
+These are essentially bread rolls made with brewer's yeast instead
+of the sourdough leavening agent. As the process is more expensive
+bread rolls like these were ultimately consumed by the noble people
+in Vienna \cite{vienna+breadrolls}.
+
+\begin{figure}[h]
+  \includegraphics[width=\textwidth]{sourdough-stove}
+  \caption{A bread made over the stove without an oven}
+  \label{sourdough-stove}
+\end{figure}
+
+Only in 1857 the French microbiologist Louis Pasteur discovered
+the process of alcoholic fermentation. He would prove that
+yeast microorganisms are the reason for alcoholic fermentation
+and not other chemical catalysts. What would then start is
+what I describe as the 150 lost years of bread making. In 1879
+the first machines and centrifuges were developed to centrifuge
+pure yeast. This yeast would be extracted from batches of sourdough.
+The pure yeast would prove to be excellent and turbocharged
+at leavening bread doughs. What would previously take 10 hours
+to leaven a bread dough could now be done within 1 hour.
+The process became much more efficient. During world war II
+the first packaged dry yeast was developed. This would ultimately
+allow bakeries and home bakers to make bread way faster.
+Thanks to pure yeast building bread making machines was
+possible. Provided you have the same temperature your yeast
+would always ferment exactly the same way. As fermentation
+times sped up the taste of the final bread would deteriorate.
+The sprouting process induced by certain enzymes is essential
+to develop a fluffier texture and better tasting crust. This
+can't be indefinitely sped up. Soon bakeries would start
+to introduce additional enzymes to achieve similar properties
+of sourdough breads in yeast based doughs. Sourdough almost
+completely vanished from the surface. Only a handful
+of true nerds would continue making breads with sourdough.
+Suddenly people started to talk more often about celiac disease
+and the role of gluten. The disease isn't old, it has first
+been described in 250 AD \cite{coeliac+disease}. People
+would note how modern bread has much more gluten compared
+to ancient bread. The bread in ancient times probably was way more flat.
+The grains over time have been bread more and more towards containing a higher
+amount of gluten. Gluten is a protein that gives modern
+bread it's typical soft fluffy crumb structure. The
+gluten proteins bind together once activated with water.
+Throughout the course of the fermentation CO2 is trapped
+in this protein matrix. The tiny created chambers expand
+during the baking process. As the dough gelatinizes while
+being heated the structure is fortified. This makes the bread appear
+soft and fluffy when tasting it. Similar to drinking
+raw cow milk your immune system might react to
+the consumed proteins. There is gluten intolerance
+and celiac disease. When people say they don't handle
+gluten will it's mostly a gluten intolerance they describe.
+Some people describe similar issues when consuming
+too much lactose. If you eat a long fermented cheese
+however most of the lactose has been fermented by
+the tiny microorganisms. People would investigate and
+note how sourdough bread can typically be handled better
+compared to plain fast made factory breads. The
+reason for this is that enzymes take time to work the dough.
+The gluten is a storage protein from the flour. Once
+sprouting is activated by adding water, the protease
+enzyme starts to convert the gluten into tinier amino acids
+that are required for sprouting. Over time you are effectively
+losing gluten as it's naturally broken down. Furthermore
+traditionally lactic acid bacteria would start to decompose
+the flour water mix. Almost everything is recycled in nature.
+Part of their diet is to consume the proteins of the dough.
+Modern bread is faster and no longer has lactic acid bacteria.
+Both factors together mean that you are consuming products
+with a much higher gluten value compared to ancient times
+when natural fermentation was used \cite{raffaella+di+cagno}.
+
+During the California gold rush french bakers brought the sourdough
+culture to northern america. A popular bread became the
+San Francisco sourdough. It's characterized by its unique
+tang (which was previously common for every bread). It
+however remained more of niche food. What really expedited
+the comeback of sourdough was the 2020 COVID-19 pandemic.
+Flour and yeast became scarce in the supermarkets. While
+flour returned yeast couldn't be found. People started
+to look for alternatives and rediscovered the ancient
+way of making sourdough bread. Soon many realized
+that making sourdough bread is more complex than modern
+yeast based bread. You need to maintain a sourdough starter
+and have it in ideal shape to properly ferment your dough.
+Furthermore compared to a yeast based dough you can't just
+punch the dough down and let the fermentation continue.
+You can overferment your dough resulting a sticky
+dough mess. This complexity lead to many bakers looking
+for help and many thriving communities formed around
+the topic of homemade bread.
+
+When interviewing Karl de Smedt (owner of the Sourdough
+Library) he said something that changed my way of thinking
+about bread: "The future of
+modern bread is in the past \cite{interview+karl+de+smedt}."

book/references.bib

@@ -23,7 +23,7 @@
                  of Dry-Baking},
  journal      = {Applied and environmental microbiology},
  publisher    = {Foods},
- url       = {https://www.mdpi.com/2304-8158/9/12/1900/pdf}
+ howpublished = {\url{https://www.mdpi.com/2304-8158/9/12/1900/pdf}}
 }
 
 @article{stiff+starter,
@@ -89,3 +89,35 @@
   howpublished = {\url{http://www.chm.bris.ac.uk/motm/acetic-acid/acetic-acidjs.htm}},
   note         = {Accessed: 2022-04-29}
 }
+
+@article{jordan+bread,
+  author    = {Amaia Arranz-Otaegui et al.},
+  title     = {Archaeobotanical evidence reveals the origins of bread 14,400 years ago in northeastern Jordan},
+  journal   = {Proc Natl Acad Sci USA},
+  year      = {2018},
+  howpublished = {\url{https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6077754/}}
+}
+
+@article{vienna+breadrolls,
+  author    = {Eben Norton Horsford},
+  title     = {Report on Vienna bread},
+  year      = {1875},
+  howpublished = {\url{https://archive.org/details/bub_gb_6jRDAAAAIAAJ/page/n100/mode/2up}},
+  note         = {Accessed: 2022-05-02}
+}
+
+@article{coeliac+disease,
+  author    = {Giovanni Battista Gasbarrini et al.},
+  title     = {Coeliac disease: an old or a new disease? History of a pathology},
+  year      = {2014},
+  journal   = {Intern Emerg Med.},
+  howpublished = {\url{https://pubmed.ncbi.nlm.nih.gov/24435555/}}
+}
+
+@article{interview+karl+de+smedt,
+  author    = {Hendrik Kleinwächter},
+  title     = {Interview with Karl de Smedt},
+  year      = {2021},
+  howpublished = {\url{https://www.youtube.com/watch?v=vfDIfkqBCuk}},
+  note         = {Accessed: 2022-05-06}
+}