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In this chapter we are looking at the basics of how sourdough ferments. In this chapter, we will cover the basics of how sourdough ferments.
For that we will first look at enzymatic reactions First, we will look at the enzymatic reactions that take place
that happen in your flour. These reactions are induced in your flour the moment you add water, triggering the fermentation
the moment you add water to your flour. They are also process. Then, in order to better understand this process, we will
the basis that trigger the fermentation process. To understand learn more about the yeast and bacterial microorganisms involved.
the fermentation process we are having a closer look at the involved
yeast and bacterial microorganisms.
\begin{figure}[!htb] \begin{figure}[!htb]
\includegraphics[width=\textwidth]{infographic-enzymes} \includegraphics[width=\textwidth]{infographic-enzymes}
@@ -14,195 +12,207 @@ yeast and bacterial microorganisms.
\section{Enzymatic reactions} \section{Enzymatic reactions}
When mixing flour and water several enzymatic reactions To understand the many enzymatic reactions that take place when flour
start. A plant produces seeds to reproduce. The seed and water are mixed, we must first understand seeds and their role in
contains all the nutrients a new plant needs to sprout. the lifecycle of wheat and other grains.
While the seed is dry the seed is in hibernation mode. It
can be sometimes be stored for several years. The moment water is added
to the seed the sprouting process starts. The seed turns
into a germ. The stored nutrients have to be converted
into something that the germ can use. The catalyst for these
reactions is water. The first roots can be produced with the stored nutrients.
Furthermore the seed typically contains the first leaves
of the plant. The first leaves are built to start the photosynthesis
process. This is the plants' engine. With energy from photosynthesis
the plant can keep growing more roots. This way more water
and nutrients can be accessed from the soil. The extended
nutrients allow the plant to form more leaves and thus
increase the photosynthetic activity.
Of course a ground flour can no longer sprout. But the enzymes Seeds are the primary means by which many plants, including wheat,
that trigger this process are still present. That's why it's reproduce. Each seed contains the embryo of another plant, and must
important to not mill the grains at a too high temperature. therefore contain all the nutrients that new plant requires to grow.
This could possibly damage some of the enzymes. Normally
the seed of the flour shields the germ against pathogens initially.
However as we grind the flour the contents of the seed
are exposed. This is ideal for our sourdough microorganisms.
The yeast can be considered a saprotrophic fungus.
They can't prepare their own food. As the enzymes start
to be activated more and more food becomes available
for the yeast and bacteria.
The two main enzymes for bread making are amylase and protease. When the seed is dry, it is in hibernation mode and can sometimes be
Understanding their role is a key puzzle piece to be able stored for several years. The moment it comes into contact with water,
to make better tasting bread at home. however, it begins to sprout. The seed turns into a germ, requiring the
stored nutrients to be converted into something the plant can use while
it grows. The catalyst that makes the associated reactions possible is water.
The seed typically contains the first prototypical leaves of the plant,
and can put down roots using the stored nutrients inside. Once those leaves
break through the soil and come into contact with the sunlight above, they
begin to photosynthesize. This process is the plant's engine, and with the
energy photosynthesis produces, the plant can continue to grow more roots,
enabling it to access additional nutrients from the soil. These additional
nutrients allow the plant to grow more leaves, increasing its photosynthetic
activity so that it can thrive in its new environment.
Of course, a ground flour can no longer sprout. But the enzymes that
trigger this process are still present. That's why it's important not to
mill grains at too high a temperature, as doing so could damage some of
these enzymes.
Normally, the grain seed shields the germ against pathogens. However, as the
grain is ground into flour, the contents of the seed are exposed. This is ideal
for our sourdough microorganisms.
% I removed the line referencing yeast as a saprotrophic fungus since you
% cover this later on in the chapter and removing that helps the text to
% flow more smoothly.
Neither the yeast nor the bacteria can prepare their own food. However, as
the enzymes are activated, the food they need becomes available, allowing them
to feed and multiply.
The two main enzymes involved in this process are \textit{amylase} and
\textit{protease}. For reasons that will soon be made clear, they are of the
utmost importance to the home baker and their role in the making of sourdough
is a key puzzle piece to making better-tasting bread.
\subsection{Amylase} \subsection{Amylase}
Sometimes when you chew on a potato or a piece of bread Sometimes, when you chew on a potato or a piece of bread for a long period
for a prolonged period of time you will notice a bit of sweetness of time, you'll perceive a sweet flavor on your tongue. That's because your
arising in your mouth. That's because your salivary glands salivary glands produce amylase. Amylase breaks down complex starch molecules
are also producing amylase. Amylase breaks down complex into easily-digestible sugars. The germ needs this to produce more plant
starch molecules into easier digestible sugars. The germ matter, and your body needs this to kick-start the digestive process. Normally,
needs this in order to be able to produce more plant matter. the microorganisms on the surface of the grain can't consume the freed maltose
Your body needs this in order to start the digesting process. molecules, which remain hidden inside the germ. But as we grind the flour, a
Normally your microorganisms can't consume the freed maltose molecules feeding frenzy takes place. Generally, the warmer the temperature, the faster
as they are hidden in the germ. But as we ground the flour this reaction occurs. That's why a long fermentation is key to making great
a feeding frenzy starts. Generally the warmer the temperature bread. It takes time for the amylase to break down most of the starch into
the faster this reaction happens. That's why a long fermentation simple sugars, which are not only consumed by the yeast but are also essential
is a key factor to make great bread. It takes time to the \textit{Maillard reaction}, responsible for enhanced browning during the
for your amylase to break down most of the starch. Furthermore baking process.
not all sugars are consumed by the yeast. Some remain and
are responsible for enhanced browning during the baking
process.
If you are a hobby brewer you will know that it's If you're a hobby brewer, you'll know that it's important to keep your beer at
important to keep your brew on certain temperatures for a certain temperatures to allow the different amylases to convert the contained
while to allow the different amylases to convert starches starches into sugar \cite{beer+amylase}. This process is so important that
into sugar \cite{beer+amylase}. There's a test frequently used by brewers there's a frequently used test to determine whether or not all the starches
to determine that all the starches have been converted. have been converted.
It's called the Iodine starch test. You take a bit of your brew
and then add a bit of iodine. If the color is blue/black This test, called the \textit{Iodine Starch Test}, involves mixing iodine into
you know that you still have starches left that haven't been a sample of your brew and checking the color. If it's blue or black, you know
converted by amylases yet. I wonder if such a test would work you still have unconverted starches. I wonder if such a test would also work
for a bread dough as well? Now industrial bakeries for bread dough?
that use yeast to make speed doughs in a short period of
time face this issue. Their approach is to add malted Industrial bakers that add especially active yeast to produce bread in a short
flour to the dough mix. The malted flour contains a lot period of time face a similar issue. Their approach is to add malted flour to
of enzymes and will thus help to have a faster fermentation the dough. The malted flour contains many enzymes and thus speeds up the
period. Check the packaging of the breads that you bought, fermentation process. The next time you're at the supermarket, check the
if you find {\it malt} in the list of ingredients chances packaging of the bread you buy. If you find {\it malt} in the list of
are that this strategy has been used. There are two categories ingredients, chances are this strategy was used.
of malts. You have enzymatically active malt and inactive
malt. The active malt hasn't been heated to above 70°C Note that there are actually two categories of malt. One is {\it enzymatically
when the amylases start to degrade under heat. The inactive active malt}, which has not been heated to above 70°C, where the amylases begin
malt has been heated to higher temperatures and thus to degrade. The other is {\it inactive malt}, which has been heated to higher
has no impact on your flour. temperatures and thus has no impact on your flour.
\subsection{Protease} \subsection{Protease}
The second very important enzyme is the protease. Proteases Just as amylase breaks starches down into simple sugars, protease breaks
break down proteins into smaller proteins or amino acids. complex proteins down into simpler proteins and amino acids. Because wheat
Gluten for instance is a storage protein built by wheat. contains gluten, a protein that's essential to the structure of bread,
The gluten is broken down and converted the moment the protease necessarily plays a crucial role in the baking of sourdough.
seed starts to sprout. That's because the seed needs
smaller amino acids to build the roots and other plant material. Since the grain seeds require smaller amino acids to build roots and other
If you ever try to make a wheat based dough and just keep plant materials, the gluten in those seeds will begin to break down the moment
it for several days at room temperature you will notice they sprout, and since adding water to flour activates those same enzymes,
how your gluten network starts to break down. The dough the same process occurs in bread dough.
no longer holds together. You can just fully tear it apart.
I have had this happen to me when I was trying to make If you've ever tried to make a wheat-based dough and kept it at room
doughs directly with dried sourdough starter. The fermentation temperature for several days, you'll have discovered for yourself that the
speed was so low that it took 3-4 days for the dough gluten network breaks down so that the dough can no longer hold together. Once
to be ready. The root cause for this issue is the protease. this happens, the dough easily tears, holds no structure, and is no
By adding water to the dough the protease was activated longer suitable for baking bread.
and started to ready amino acids for the germ in order to be
able to sprout. Another interesting experiment that viusalises This happened to me once when I tried to make sourdough directly from a dried
the importance of protease is the following. Try to make a starter. At three to four days, the fermentation speed was so slow that the
fast dough within 1-2 hours. Simply use a large quantity gluten network broke down. The root cause for this issue was protease.
of dry yeast. Your dough will be leavened and increase in size.
Bake your dough and notice the crumb of your baked dough. By adding water to your dough, you activate the protease, and this gets to work
You will notice that the crumb is quite dense and not as in readying amino acids for the germ.
fluffy as it could be. That's because the protease enzyme
didn't have enough time to do its job. At the start Here's another interesting experiment you can try to better visualize the
when kneading your dough is very elastic. It holds together importance of protease: Make a fast-proofing dough using a large quantity
very well. Over the course of the fermentation process of active dry yeast. In one to two hours, your dough should have leavened and
your dough will become more extensible \cite{protease+enzyme+bread}. increased in size. Bake it, then examine the crumb structure. You should see
Some of the gluten bonds start to naturally break that it's quite dense and nowhere near as fluffy as it could have been. That's
down due to the protease proteolysis. This makes it easier because the protease enzyme wasn't given enough time to do its job.
for your dough to be inflated. That's why a long
fermentation process is important when you want to At the start, while kneading, a dough becomes elastic and holds together very
achieve very fluffy and open crumbs with your sourdough well. As that dough ferments, however, it becomes more loose and extensible
bread. Next to using great ingredients, the long and \cite{protease+enzyme+bread}. This is because some of the gluten bonds have
slow fermentation is one of the main reasons why been broken down naturally by the protease through a process known as
Neapolitan pizza tastes so great. The soft and fluffy \textit{proteolysis}. This is what makes it easier for the yeast to inflate the
edge of the pizza is achieved because of the protease dough, and it's why a long fermentation process is critical when you want to
creating a very extensible easy to inflate dough. Because achieve a fluffy, open crumb with your sourdough bread.
the fermentation process is typically longer than 8
hours a flour with a higher gluten content is used. There Aside from using great ingredients, the slow fermentation process is one of the
is more gluten that can be broken down by the protease. main reasons Neapolitan pizza tastes so great; because the protease creates an
By using a weaker flour you might end up with a dough extensible, easy-to-inflate dough, a soft and airy edge is achieved.
that's already broken down too much and will then tear
when trying to make a pizza pie. Traditionally the pizza Because the fermentation process typically takes longer than eight hours, a
has probably been made with sourdough. In modern times flour with a higher gluten content should be used. This gives the dough more
it is made with yeast as handling a yeast based time to be broken down by the protease without negatively affecting its
dough can be done easier on a larger scale. The dough elasticity. If you were to use a weaker flour, you might end up with a dough
stays good for a longer period of time. If you were to use that's broken down so much that it tears during stretching, making it
sourdough you might have a window of 30-90 minutes when impossible, for example, to shape it into a pizza pie.
your dough is perfect. Afterwards the dough might
start to deteriorate because of bacteria breaking Traditionally, pizza has been made with sourdough, but in modern times it is
down the gluten network too much. made with active dry yeast, as the dough stays good for a longer period of time
and is much easier to handle on a commercial scale. If you were to use
sourdough, you might have a window of thirty to ninety minutes before the dough
begins to deteriorate, both because of the protease acting for a longer period
of time and the byproducts of bacteria, which we'll discuss in more detail later
in this chapter.
\subsection{Improving enzymatic activity} \subsection{Improving enzymatic activity}
As explained previously malt is a common trick used As explained previously, malt is a common trick used to speed up enzymatic
to speed up enzymatic activity. I personally prefer activity. Personally, however, I prefer to avoid malt and instead use a
to avoid malt in most of my recipes. Instead I use trick I learned while making whole-wheat breads.
a trick I observed when making whole wheat doughs.
No matter what I tried I could never achieve baking When I first started making whole-wheat bread, I could never achieve the
a whole wheat bread with the desired crust and crumb crust, crumb, or texture I desired no matter what I tried. Instead, my dough
texture I was looking for. My doughs would tend to tended to overferment rather quickly. When using a white flour with a similar
overferment relatively quickly. When using a flower gluten content, however, my bread always turned out great.
with a similar amount of gluten that didn't contain
bran and other outer parts of the grain my doughs turned At the time, I utilized an extended autolyse, which is just a fancy word for
out great. I was utilizing an extended autolyse. mixing flour and water in advance and then letting the mixture sit. Most
That's a fancy word for just mixing flour and water in recipes call for it as the process gives the dough an enzymatic head start, and
advance and letting that mixture sit. Most recipes in general it's a great idea. However, as an equally effective alternative,
call for it as the help to make a dough that has already you could simply reduce the amount of leavening agent used (in the case of
started to break down by enzymes. In general it's a great sourdough, this would be your starter). This would allow the same biochemical
idea but at the same time you can just reduce the amount reactions to occur at roughly the same rate without requiring you to mix your
of leavening agent you use. This way the same biochemical dough several times. My whole wheat game improved dramatically after I stopped
reactions happen and you don't have to mix your dough autolysing my doughs.
several times. My whole wheat game drastically improved
when I stopped using the autolysis. It makes sense if I Now that I've had time to think about it, the result I observed makes sense.
think about it now. The first parts of the seed that In nature, the outer parts of the seed come into contact with water first, and
are in contact with water are the outer parts. Water only after penetrating this barrier would the water slowly find its way to the
will slowly enter the center parts of the grain. The center of the grain. The seed needs to sprout first to outcompete other nearby
moment the seed starts to sprout it needs to outcompete seeds, requiring water to enter quickly. Yet the seed must also defend itself
other nearby seeds. Furthermore it also directly becomes against animals and potentially hazardous bacteria and fungi, requiring some
exposed to other animals and potential hazardous bacteria barrier to protect the embryo inside. A way for the plant to achieve both goals
and fungi. To accelerate this process most of the enzymes would be for most of the enzymes to exist in the outer parts of the hull. As a
of the grain are in the outer parts of the hull. They result, they are activated first (source needed). Therefore, by just adding a
are being activated first (source needed). So by just little bit of whole flour to your dough, you should be able to significantly
adding a little bit of whole flour to your dough you improve the enzymatic activity of your dough. That's why, for plain white flour
will improve enzymatic activity of your dough. That's doughs, I usually add 10\textendash20\% whole-wheat flour.
why most of my plain flour doughs typically contain
at least 10-20 percent whole wheat flour.
\begin{figure} \begin{figure}
\includegraphics[width=\textwidth]{whole-wheat-crumb} \includegraphics[width=\textwidth]{whole-wheat-crumb}
\caption{A whole wheat sourdough bread} \caption{A whole-wheat sourdough bread}
\label{whole-wheat-crumb} \label{whole-wheat-crumb}
\end{figure} \end{figure}
By understanding the 2 key enzymes amylase and protease By understanding the two key enzymes \textit{amylase} and \textit{protease}, you
you will better be able to understand how to make a will be better equipped to make bread to your liking. Do you prefer a softer
dough to your liking. Would you like a dough a softer or stiffer crumb? Do you desire a lighter or darker crust? Do you wish to reduce
or stiffer crumb? Would you like to achieve a darker crust? the amount of gluten in your final bread? These are all factors that you can
Would you like to reduce the amount of gluten in your tweak just by adjusting the speed of your dough's fermentation.
final bread? These are all factors you can influence
by adjusting the speed of fermentation.
\section{Yeast} \section{Yeast}
Yeasts are single celled microorganisms that are part of % Yeast is both the singular and plural form of the word unless you're
the fungus kingdom. Yeast spores that are hundreds % specifically referencing a plural number of varieties or types, in which case
of million years old have been identified by scientists. % "yeasts" would be correct.
There is a wide variety of species and so far around 1500 Yeast are single celled microorganisms belonging to the fungi kingdom, and
different species have been recognized. Yeasts are not creating spores that are hundreds of millions of years old have been identified by
a mycelium network like mold does for instance scientists. There are a wide variety of species: So far, about 1,500 have been
\cite{molecular+mechanisms+yeast}. identified. Unlike other members of the fungi kingdom, such as mold, yeast do
not ordinarily create a mycelium network \cite{molecular+mechanisms+yeast}
\footnote{For one interesting exception, skip ahead to the end of this
section.}.
\begin{figure}[!htb] \begin{figure}[!htb]
\centering \centering
@@ -211,106 +221,105 @@ a mycelium network like mold does for instance
\label{saccharomyces-cerevisiae-microscope} \label{saccharomyces-cerevisiae-microscope}
\end{figure} \end{figure}
Yeast are saprotrophic fungi. This means that they do not produce their own
food, but instead rely on external sources that they can decompose and break
down into compounds that are more easily metabolized.
Yeasts are saprotrophic fungi. This means they are not Yeast breaks down carbohydrates into carbon dioxide and alcohol in what we today
producing their own food. They rely on external food sources refer to as the fermentation process. This process has been known for thousands
which they decompose and break down. For yeasts of years and has been used since ancient times for the making of bread as well
carbohydrates and broken down to carbon dioxide and as alcoholic beverages.
alcohols. The products of this fermentation process
have been used for thousands of years when making
bread or alcoholic beverages. Yeasts can grow
in both aerobic and anaerobic conditions. When oxygen
is present the yeast almost completely produces
carbon dioxide and water. When no oxygen is present
the yeast starts switches its metabolism. The
yeast starts to produce alcoholic compounds \cite{effects+oxygen+yeast+growth}.
The temperatures at which the yeast grows vary. Some
yeasts such as {\it Leucosporidium frigidum} grows
best at temperatures between -2°C up to 20°C. Other
yeast grows better at higher temperatures. The warmer
it is the faster the yeast's metabolism works. The yeast
that you cultivate in your sourdough starter works best
at the temperatures where the grain was grown and at
the point when it was harvested. So if you are from a
cooler place and cultivate a sourdough starter from
a nordic rye variety, then chances are your yeast
prefers this colder environment. As an example
beer makers discovered that a beneficial yeast lives
in the cold caves around the city of Pilsen, Czech Republic.
This yeast has produced excellent tasting beers at
lower temperatures. Varieties of these strains
are now used to make popular lager beers.
Yeasts in general are very common in the environment. Yeast can grow and multiply under both aerobic and anaerobic conditions. When
They can be found on cereal grains, fruits, other plants oxygen is present, they produce carbon dioxide and water almost exclusively.
in the soil and also in your gut. Very little is known When oxygen is not present, their metabolism changes to produce alcoholic
about the ecology of why yeasts we use for baking compounds \cite{effects+oxygen+yeast+growth}.
are cultivating the leaves of the plants. The plants
are protected via the cell walls and hardly any
fungi and other bacteria can penetrate. Some fungi and
bacteria are producing enzymes that are able
to break down the cell walls and infect the plant.
There are fungi and bacteria that live within the plant
without causing any distress. These are known as {\it endophytes}.
They are not damaging the plant per se. In fact they are
living in a symbiotic relationship with the host. They
help the plant to protect itself from additional pathogens
that might enter through the leaves of the plant. They
help with water stress, heat stress and nutrient availability.
In exchange for the service they receive carbon for energy
from the plant host. They are not always strictly mutualistic though.
Sometimes under stress conditions they can become pathogens
on their own \cite{endophytes+in+plants} and decay begin
decaying the plant.
The yeasts we use for baking are The temperatures at which yeast grows varies. Some yeasts, such as
living as as epiphytes on the plant. Compared to {\it Leucosporidium frigidum}, do best at temperatures ranging from -2°C to
the previously mentioned endophytes they are not 20°C, while others prefer higher temperatures. In general, the warmer the
breaching the walls of the cells. Most of them environment, the faster the yeast's metabolism. The variety of yeast
receive nutrients from rain water, the air or other animals. that you cultivate in your sourdough starter should work best within the range
These sources also include honeydew produced of temperatures where the grain was grown and harvested. So, if you are from a
by aphids. Pollen that lands on the leaf's surface cooler place and cultivate a sourdough starter from a nordic rye variety,
is an additional source of food. Interestingly chances are your yeast will prefer a colder environment.
though when you remove that external food source,
you still find a large variety of epiphytic fungi As an example, beer makers discovered a beneficial yeast living in the cold
and bacteria on the plant's surface. The food caves around the city of Pilsen, Czech Republic. This yeast has since become
for them is coming directly from the plant it seems. known for producing excellent beers at lower temperatures and varieties of
Some research has shown that the plants are these strains are now used for brewing popular lagers.
on purpose releasing some compounds such as sugars,
organic acids, amino acids, some methanol and various Yeasts in general are very common organisms. They can be found on cereal
salts via the surface. These nutrients would grains, fruits, and many other plants in the soil. They can even be found
then attract the epiphytes to live on the surface. inside your gut! As it happens, the types of yeast we use for baking are
The plants benefit from enhanced protection against cultivated on the leaves of plants, though very little is known about the
mold and other pathogens. It is in the best interest ecology involved.
of the epiphytes to keep the plants alive
as long as possible \cite{leaf+surface+sugars+epiphytes}. Plants are protected by thick cell walls that few fungi or bacteria can
More and more research is conducted on using yeasts penetrate. However, there are some species that produce enzymes capable of
as a biocontrol agents to protect plants. These bio-agents breaking down those cell walls so they can infect the plant.
would be food-safe as yeasts are generally considered save.
The yeasts would start to grow on the leaves on the plant Some fungi and bacteria live inside plants without causing them any distress.
and essentially shield the plants from other molds. This These are known as {\it endophytes}. Not only do they \textit{not} damage their
could be a game changer for wineyeards suffering from mildew. host, they actually live in a symbiotic relationship, helping the plants in
This could also be helpful to shield the plant against the which they dwell to protect themselves from other pathogens that might also
psychoactive ergot fungus. The ergot fungus likes to grow come to infect them through their leaves. In addition to this protection, they
in more humid colder environments and poses a huge also help with water and heat stress, as well as the availability of nutrients.
problem to rye farmers. The fungus parasites the plant In exchange for their service to their host plants, these fungi and bacteria
and infects it. Consumption of ergot is not recommended receive carbon for energy.
as it is highly toxic to the liver. That's why lawmakers
have recently reduced the amount of allowed ergot contamination However, the relationship between endophyte and plant is not always mutually
in rye flour. Another interesting experiment from Italian scientists beneficial, and sometimes, under stress, they become invasive pathogens and
visualized how important yeasts could be when protecting ultimately cause their host to decay \cite{endophytes+in+plants}.
plants. They added tiny incisions into some of the grapes.
They would then infect some of the damaged surfaces with There are other microorganisms that, unlike endophytes, do not penetrate cell
mold. The other wounds they infected with some of the 150 walls but instead live on the plant's surface and receive nutrients from rain
different wild yeast strains isolated from the leaves plus water, the air, or other animals. Some even feed on the honeydew produced by
the mold. When mixing the mold with the yeast the grape aphids or the pollen that lands on the surface of the leaves. Such organisms
are called \textit{epiphytes}, and included among them are the types of yeast
we use for baking.
Interestingly, when you remove external food sources, a large number of
epiphytic fungi and bacteria can still be found on the plant's surface,
suggesting that they must somehow be feeding directly from the plant.
Indeed, there is some research indicating that some plants intentionally release
compounds such as sugars, organic and amino acids, methanol, and various
salts along the surface. These nutrients would then attract the epiphytes that
live on the plant's surface.
Epiphytes are advantageous to a plant's survival, as they are provided with
enhanced protection against mold and other pathogens. Indeed, it is in the
best interest of the epiphytes to keep their host plants alive for as long as
possible \cite{leaf+surface+sugars+epiphytes}.
More research is conducted every day in ways that yeasts can be used as
biocontrol agents to protect plants, the advantage being that these bio-agents
would be food-safe as the relevant strains of yeast are generally considered
harmless to humans. The yeasts would grow and multiply on the leaves,
esentially shielding them from other types of mold. This could be a potential
game changer for vineyards that suffer from mildew.
Such bio-agents could also be used to shield plants against the psychoactive
ergot fungus, which likes to grow in colder, more humid environments and
poses a significant problem for rye farmers. Because it infects the grain
and makes it unfit for consumption due to its high toxicity to the liver,
lawmakers have recently reduced the amount of allowed ergot contamination in
rye flour.
There is another interesting experiment performed by Italian scientists that
shows how crucial yeasts could be in protecting our crops. First, they made
tiny incisions into some of the grapes on a vine. Then, they infected the
wounds with mold. Some incisions were only infected with mold. Others were also
innoculated with some of the 150 different wild yeast strains isolated from the
leaves. They found that when the wound was innoculated with yeast, the grape
sustained no significant damage \cite{yeasts+biocontrol+agent}. sustained no significant damage \cite{yeasts+biocontrol+agent}.
In another experiment however scientists have shown
how the brewer's yeast became an aggressive pathogen to wine plants. Intriguingly, there was also an experiment performed that showed how brewer's
Initially the yeast lived in symbiosis with the plant. After the grapevine yeast could function as an aggressive pathogen to grape vines. Initially, the
sustained damages the yeast became opportunistic and started to yeast lived in symbiosis with the plants, but after the vines sustained heavy
attack the plant event producing hyphae to deeply damage, the yeast became opportunistic and started to attack, even going so far
penetrate the plants tissue. as to produce hyphae, the mycellium network normally associated with a fungus,
so that they could penetrate the tissue of the plants.
\section{Bacteria} \section{Bacteria}

11
book/intro/acknowledgements.tex
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@@ -1,14 +1,13 @@
This book would not have been possible without the help of the community. This book would not have been possible without the help of the community.
All the donations have made it possible that I was able to take Because of the donations received, I have been able to take time off from
some time off from my job and YouTube to write this free book. my job and from YouTube to write it. By providing this information free
By providing this information free to everyone we can of charge, we can help more people around the world bake delicious sourdough
enable more people around the world to bake delicious bread at home. Thank you very much!\\
sourdough bread at home. Thank you very much!\\
\begin{filecontents}{supporters.csv} \begin{filecontents}{supporters.csv}
\end{filecontents} \end{filecontents}
{\large All supporters sorted by name} {\large All supporters, sorted by name:}
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begin table=\begin{longtable}, begin table=\begin{longtable},