mchapman/the-sourdough-framework
1
0
Fork 0
mirror of https://github.com/hendricius/the-sourdough-framework synced 2025-11-10 13:11:13 -06:00
Code Issues Actions Packages Projects Releases Wiki Activity

How sourdough works (#208)

Browse Source 
* Use whole-wheat consistantly

* Review how sourdough works chapter
This commit is contained in:
cedounet
2023-09-04 09:25:13 +01:00
committed by GitHub
parent 233ac8d4c7
commit 2aedda0474
1 changed files with 30 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

60
book/basics/how-sourdough-works.tex
View File

@@ -41,10 +41,12 @@ activity so that it can thrive in its new environment.
Of course, a ground flour can no longer sprout. But the enzymes that 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 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 mill grains at too high a temperature, as doing so could damage some of
these enzymes\footnote{In a recent study tests have shown that milling flour these enzymes\footnote{In a recent
study~\cite{milling+commercial+home+mill+comparison} tests have shown that
milling flour
at home with a small mill had no significant negative impact on the resulting at home with a small mill had no significant negative impact on the resulting
bread quality compared to milled flour from temperature-regulated large-scale bread quality compared to milled flour from temperature-regulated large-scale
mills~\cite{milling+commercial+home+mill+comparison}.}. mills.}.
Normally, the grain seed shields the germ against pathogens. However, as the 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 grain is ground into flour, the contents of the seed are exposed. This is ideal
@@ -83,15 +85,14 @@ certain temperatures to allow the different amylases to convert the contained
starches into sugar~\cite{beer+amylase}. This process is so important that starches into sugar~\cite{beer+amylase}. This process is so important that
there's a frequently used test to determine whether or not all the starches there's a frequently used test to determine whether or not all the starches
have been converted. have been converted.
This test, called the \emph{Iodine Starch Test}, involves mixing iodine into This test, called the \emph{Iodine Starch Test}, involves mixing iodine into
a sample of your brew and checking the color. If it's blue or black, you know a sample of your brew and checking the color. If it's blue or black, you know
you still have unconverted starches. I~wonder if such a test would also work you still have unconverted starches. I~wonder if such a test would also work
for bread dough? for bread dough?
Industrial bakers that add especially active yeast to produce bread in a short Industrial bakers who add especially active yeast to produce bread in a short
period of time face a similar issue. Their approach is to add malted flour to period of time face a similar issue. Their approach is to add malted flour to
the dough. The malted flour contains many enzymes and thus speeds up the the dough, this malted flour contains many enzymes and thus speeds up the
fermentation process. The next time you're at the supermarket, check the fermentation process. The next time you're at the supermarket, check the
packaging of the bread you buy. If you find \emph{malt} in the list of packaging of the bread you buy. If you find \emph{malt} in the list of
ingredients, chances are this strategy was used. ingredients, chances are this strategy was used.
@@ -115,14 +116,13 @@ the same process occurs in bread dough.
If you've ever tried to make a wheat-based dough and kept it at room If you've ever tried to make a wheat-based dough and kept it at room
temperature for several days, you'll have discovered for yourself that the temperature for several days, you'll have discovered for yourself that the
gluten network breaks down so that the dough can no longer hold together. Once gluten network breaks down to the point that the dough can no longer hold together. Once
this happens, the dough easily tears, holds no structure, and is no this happens, the dough easily tears, holds no structure, and is no
longer suitable for baking bread. longer suitable for baking bread.
This happened to me once when I~tried to make sourdough directly from a dried This happened to me once when I~tried to make sourdough directly from a dried
starter. At three to four days, the fermentation speed was so slow that the starter. At three to four days, the fermentation speed was so slow that the
gluten network broke down. The root cause for this issue was protease. gluten network broke down. The root cause for this issue was protease.
By adding water to your dough, you activate the protease, and this gets to work By adding water to your dough, you activate the protease, and this gets to work
in readying amino acids for the germ. in readying amino acids for the germ.
@@ -144,7 +144,7 @@ achieve a fluffy, open crumb with your sourdough bread.
Aside from using great ingredients, the slow fermentation process is one of the Aside from using great ingredients, the slow fermentation process is one of the
main reasons Neapolitan pizza tastes so great: because the protease creates an main reasons Neapolitan pizza tastes so great: because the protease creates an
extensible, easy-to-inflate dough, a soft and airy edge is achieved. extensible and easy-to-inflate dough a soft and airy edge is achieved.
Because the fermentation process typically takes longer than 8~hours, a Because the fermentation process typically takes longer than 8~hours, a
flour with a higher gluten content should be used. This gives the dough more flour with a higher gluten content should be used. This gives the dough more
@@ -154,10 +154,10 @@ that's broken down so much that it tears during stretching, making it
impossible, for example, to shape it into a pizza pie. impossible, for example, to shape it into a pizza pie.
Traditionally, pizza has been made with sourdough, but in modern times it is Traditionally, pizza has been made with sourdough, but in modern times it is
made with active dry yeast, as the dough stays good for a longer period of time 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 it 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 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 begins to deteriorate, due to both the protease acting for a longer period
of time and the byproducts of bacteria, which we'll discuss in more detail later of time and the byproducts of bacteria, which we'll discuss in more detail later
in this chapter. in this chapter.
@@ -176,10 +176,10 @@ At the time, I~utilized an extended autolyse, which is just a fancy word for
mixing flour and water in advance and then letting the mixture sit. Most mixing flour and water in advance and then letting the mixture sit. Most
recipes call for it as the process gives the dough an enzymatic head start, and recipes call for it as the process gives the dough an enzymatic head start, and
in general it's a great idea. However, as an equally effective alternative, in general it's a great idea. However, as an equally effective alternative,
you could simply reduce the amount of leavening agent used (in the case of you could simply reduce the amount of leavening agent used --- in the case of
sourdough, this would be your starter). This would allow the same biochemical sourdough, this would be your starter. This would allow the same biochemical
reactions to occur at roughly the same rate without requiring you to mix your reactions to occur at roughly the same rate without requiring you to mix your
dough several times. My whole wheat game improved dramatically after I~stopped dough several times. My whole-wheat game improved dramatically after I~stopped
autolysing my doughs. autolysing my doughs.
Now that I've had time to think about it, the result I~observed makes sense. Now that I've had time to think about it, the result I~observed makes sense.
@@ -201,7 +201,6 @@ doughs, I~usually add 10\textendash20\% whole-wheat flour.
\label{whole-wheat-crumb} \label{whole-wheat-crumb}
\end{figure} \end{figure}
By understanding the two key enzymes \emph{amylase} and \emph{protease}, you By understanding the two key enzymes \emph{amylase} and \emph{protease}, you
will be better equipped to make bread to your liking. Do you prefer a softer will be better equipped to make bread to your liking. Do you prefer a softer
or stiffer crumb? Do you desire a lighter or darker crust? Do you wish to reduce or stiffer crumb? Do you desire a lighter or darker crust? Do you wish to reduce
@@ -212,14 +211,16 @@ tweak just by adjusting the speed of your dough's fermentation.
Yeasts are single-celled microorganisms belonging to the fungi kingdom, and Yeasts are single-celled microorganisms belonging to the fungi kingdom, and
spores that are hundreds of millions of years old have been identified by spores that are hundreds of millions of years old have been identified by
scientists. There are a wide variety of species --- so far, about \num{1500} have been scientists. There are a wide variety of species --- so far, about \num{1500}
identified. Unlike other members of the fungi kingdom such as mold, yeasts do have been identified. Unlike other members of the fungi kingdom such as mold,
not ordinarily create a mycelium network~\cite{molecular+mechanisms+yeast}.\footnote{For yeasts do not ordinarily create a mycelium
one interesting exception, skip ahead to the end of this section.} network~\cite{molecular+mechanisms+yeast}.\footnote{For one interesting
exception, skip ahead to the end of this section on
page~\pageref{aggressive-yeast}.}
\begin{figure}[!htb] \begin{figure}[!htb]
\begin{center} \begin{center}
\includegraphics[width=1.0\textwidth]{saccharomyces-cerevisiae-microscope} \includegraphics[width=0.8\textwidth]{saccharomyces-cerevisiae-microscope}
\caption[Brewer's yeast]{Saccharomyces cerevisiae: Brewer's yeast under the \caption[Brewer's yeast]{Saccharomyces cerevisiae: Brewer's yeast under the
microscope.}% microscope.}%
\label{saccharomyces-cerevisiae-microscope} \label{saccharomyces-cerevisiae-microscope}
@@ -228,11 +229,10 @@ one interesting exception, skip ahead to the end of this section.}
Yeasts are saprotrophic fungi. This means that they do not produce their own Yeasts 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 food, but instead rely on external sources that they can decompose and break
down into compounds that are more easily metabolized. down into compounds that are more easily metabolized. What we today
refer to as the fermentation process, is the yeast breaking down carbohydrates
Yeast breaks down carbohydrates into carbon dioxide and alcohol in what we today into carbon dioxide and alcohol. This process has been known for thousands
refer to as the fermentation process. This process has been known for thousands of years, and has been used since ancient times for the making of bread as well
of years and has been used since ancient times for the making of bread as well
as alcoholic beverages. as alcoholic beverages.
Yeast can grow and multiply under both aerobic and anaerobic conditions. When Yeast can grow and multiply under both aerobic and anaerobic conditions. When
@@ -250,7 +250,7 @@ cooler place and cultivate a sourdough starter from a nordic rye variety,
chances are your yeast will prefer a colder environment. chances are your yeast will prefer a colder environment.
As an example, beer makers discovered a beneficial yeast living in the cold As an example, beer makers discovered a beneficial yeast living in the cold
caves around the city of Pilsen, Czech Republic. This yeast has since become caves around the city of Pilsen, Czech~Republic. This yeast has since become
known for producing excellent beers at lower temperatures and varieties of known for producing excellent beers at lower temperatures and varieties of
these strains are now used for brewing popular lagers. these strains are now used for brewing popular lagers.
@@ -266,7 +266,7 @@ breaking down those cell walls so they can infect the plant.
Some fungi and bacteria live inside plants without causing them any distress. Some fungi and bacteria live inside plants without causing them any distress.
These are known as \emph{endophytes}. Not only do they \emph{not} damage their These are known as \emph{endophytes}. Not only do they \emph{not} damage their
host, they actually live in a symbiotic relationship, helping the plants in host, they actually live in a symbiotic relationship. They help the plants in
which they dwell to protect themselves from other pathogens that might also which they dwell to protect themselves from other pathogens that might also
come to infect them through their leaves. In addition to this protection, they come to infect them through their leaves. In addition to this protection, they
also help with water and heat stress, as well as the availability of nutrients. also help with water and heat stress, as well as the availability of nutrients.
@@ -319,6 +319,7 @@ inoculated with some of the 150 different wild yeast strains isolated from the
leaves. They found that when the wound was inoculated with yeast, the grape leaves. They found that when the wound was inoculated with yeast, the grape
sustained no significant damage~\cite{yeasts+biocontrol+agent}. sustained no significant damage~\cite{yeasts+biocontrol+agent}.
\phantomsection \label{aggressive-yeast}%
Intriguingly, there was also an experiment performed that showed how brewer's Intriguingly, there was also an experiment performed that showed how brewer's
yeast could function as an aggressive pathogen to grapevines. Initially, the yeast could function as an aggressive pathogen to grapevines. Initially, the
yeast lived in symbiosis with the plants, but after the vines sustained heavy yeast lived in symbiosis with the plants, but after the vines sustained heavy
@@ -329,8 +330,8 @@ so that they could penetrate the tissue of the plants.
\section{Bacteria} \section{Bacteria}
The other most dominant microbial antagonists in your sourdough are bacteria. The other most dominant microbial antagonists in your sourdough are bacteria.
In fact, they are so dominant that they outnumber the yeast in your dough 100 In fact, they are so dominant that they outnumber the yeast in your dough
to 1. Whereas yeast provides leavening power, bacteria create the distinct 100~to~1. Whereas yeast provides leavening power, bacteria create the distinct
flavours for which sourdough has been named. These are due to the acidic flavours for which sourdough has been named. These are due to the acidic
byproducts that result from bacterial feeding. As a bonus, these acids byproducts that result from bacterial feeding. As a bonus, these acids
can significantly increase the shelf life of sourdough can significantly increase the shelf life of sourdough
@@ -384,7 +385,6 @@ fight would have to take place everywhere in the dough and not just in an
isolated patch. More research on this topic is required to get a better understanding of isolated patch. More research on this topic is required to get a better understanding of
the details of the relationship between yeast and bacteria. the details of the relationship between yeast and bacteria.
One other interesting trait of sourdough bacteria worth mentioning is their One other interesting trait of sourdough bacteria worth mentioning is their
ability to break down and consume the proteins in your dough. If you've baked ability to break down and consume the proteins in your dough. If you've baked
sourdough before, chances are you've experienced this firsthand. You'll recall sourdough before, chances are you've experienced this firsthand. You'll recall