diff --git a/book/book.tex b/book/book.tex index c5d9a17..d3cd745 100644 --- a/book/book.tex +++ b/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} diff --git a/book/history/einkorn-crumb.jpg b/book/history/einkorn-crumb.jpg new file mode 100644 index 0000000..71dd750 Binary files /dev/null and b/book/history/einkorn-crumb.jpg differ diff --git a/book/history/sourdough-history.tex b/book/history/sourdough-history.tex new file mode 100644 index 0000000..4a3353d --- /dev/null +++ b/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}." diff --git a/book/history/sourdough-stove.jpg b/book/history/sourdough-stove.jpg new file mode 100644 index 0000000..55160ff Binary files /dev/null and b/book/history/sourdough-stove.jpg differ diff --git a/book/references.bib b/book/references.bib index 9736f2a..7cc9227 100644 --- a/book/references.bib +++ b/book/references.bib @@ -17,13 +17,13 @@ } @article{rye-defects, - author = {Marie Oest et al.}, - title = {Rye Bread Defects: Analysis of Composition and - Further Influence Factors as Determinants - of Dry-Baking}, - journal = {Applied and environmental microbiology}, - publisher = {Foods}, - url = {https://www.mdpi.com/2304-8158/9/12/1900/pdf} + author = {Marie Oest et al.}, + title = {Rye Bread Defects: Analysis of Composition and + Further Influence Factors as Determinants + of Dry-Baking}, + journal = {Applied and environmental microbiology}, + publisher = {Foods}, + howpublished = {\url{https://www.mdpi.com/2304-8158/9/12/1900/pdf}} } @article{stiff+starter, @@ -88,4 +88,36 @@ author = {chm.bris.ac.uk}, 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} } \ No newline at end of file