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https://github.com/hendricius/the-sourdough-framework
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224 lines
11 KiB
TeX
224 lines
11 KiB
TeX
\section{Baking in the tropics}
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Depending on the temperature your fermentation speed adapts.
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In a warmer environment everything is faster. In a colder
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environment everything is slower.
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This includes the speed at which your sourdough ferments
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the dough but also the speed of enzymatic reactions. The
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amylase and protease enzymes work faster, making more
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sugars available and degrading the gluten proteins.
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At around 22°C in my kitchen my bulk fermentation is ready
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after around 10 hours. I am using around 20 percent of sourdough
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starter based on the flour. In summer times the temperatures
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in my kitchen sometimes increase to 25°C. In that case
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I am reducing the sourdough starter to around 10 percent.
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If I wouldn't do that my fermentation would be done after
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around 4-7 hours. The problem is that the dough is quite
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unstable when fermenting at this high speed. This means
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that you are easily running into issues of overfermentation.
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Finding the perfect sweet spot between fermenting enough
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and not too much is becoming much harder. Normally you might
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have a time window of 1 hour. But at the rapid speed it
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might be reduced to a time window of 20 minutes. Now at
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30°C ambient temperature things are way faster. Your bulk
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fermentation might be complete in 2-4 hours when using
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10-20 percent starter. Proofing your dough in the fridge
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becomes almost impossible. As your dough cools down in the
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fridge the fermentation also slows down. However cooling the
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dough down from 30°C to 4-6°C in your fridge takes much
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longer. Your dough is much more active compared to a dough
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that starts at a temperature of 20-25°C. You might
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end up overproofing your dough if you leave it overnight
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in the fridge.
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That's why I recommend that you reduce the amount of starter
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that you use in the tropics to something at around 1-5 percent
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based on the flour. This will slow down the fermentation
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process significantly and provides you a bigger window
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of time. Try to aim for an overall bulk fermentation of at
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least 8-10 hours. Reduce the amount of starter to get there.
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When making a dough try to use the same water temperature
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as your ambient temperature. Assuming that the temperature
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will climb to 30°C, try to start your dough directly
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with 30°C water. This means that you can carefully rely on
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a small fermentation probe that visualizes your fermentation
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progress. The probe only works reliably if your dough temperature
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is equal to your ambient temperature. Else the sample heats
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up or cools down faster. So tread carefully when using
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the sample in this case. It's always better to stop
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the fermentation a little too early rather than too late.
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Stretch and folds during the bulk fermentation
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will help you to develop a better look and feel for
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the dough. An expensive but possibly useful tool
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could be a pH meter that allows you to perfectly
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measure how much acidity has been created by the
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lactic and acetic acid bacteria. In this case measure
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the pH repeatedly and figure out a value that works
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for your sourdough. In my case I tend to end bulk
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fermentation at a pH of around 4.1. Please don't just
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follow my pH value, it's very individual. Keep measuring
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with different doughs to find out a value that works for you.
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\section{My bread stays flat}
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\label{sec:flat-bread-crumb}
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A flat bread is in most cases related to your gluten
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network breaking down fully. This is not bad, this
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means you are eating a fully fermented food. However
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from a taste and consistency perspective it might be
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that your bread tastes too sour, or is not fluffy anymore.
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Please also note that you can only make bread with
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great oven spring when making wheat based doughs. When
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starting with this hobby I always wondered why my rye
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breads would turn out so flat. Rye has gluten yes, but
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small particles called {\it hemicelluloses} (arabinoxylan and beta-glucan) \cite{rye-defects}.
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prevent the dough from developing a gluten network like you can
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do with wheat. Your efforts are in vain, your dough will
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stay flat. Only spelt and wheat based doughs have the capability
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to retain the CO2 created by the fermentation.
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In most cases something is probably off with your
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sourdough starter. This very often happens when the starter
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is still relatively young and hasn't yet matured
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at fermenting flour. Over time your sourdough
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starter is going to become better and better at fermenting
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flour. Keep your sourdough starter at room temperature
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and then apply daily feedings with a 1:5:5 ratio.
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This would be 1 part old starter, 5 parts flour,
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5 parts water. This allows you to achieve a better
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balance of yeast and bacteria in your sourdough.
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Even better could be the use of a stiff sourdough
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starter. The stiff sourdough starter boosts
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the yeast part of your starter. This allows you
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to have less bacterial fermentation, resulting
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in a stronger gluten network towards the end
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of the fermentation \cite{stiff+starter}. Please
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also refer to the section ~\ref{sec:flat-bread-crumb} where
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I explained more about overfermented doughs.
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\begin{figure}[!htb]
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\includegraphics[width=\textwidth]{stiff-starter-conversion}
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\caption{The process to convert your starter into a stiff starter.}
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\label{fig:stiff-starter-conversion}
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\end{figure}
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Furthermore a stronger flour containing more gluten
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will help you to push the fermentation further. This
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is because your flour contains more gluten and will
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take longer to be broken down by your bacteria. Ultimately
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if fermented for too long your dough is also going
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to be broken down and will become sticky and flat.
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To debug whether the excess bacterial fermentation is the issue,
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simply taste your dough. Does it taste very sour? If yes,
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that's a good indicator. When working the dough, does it
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suddenly become very sticky after a few hours? That's a
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another good indicator. Please also use your nose to note
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the smell of the dough. It shouldn't be too pungent.
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\section{I want more tang in my bread}
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To achieve more tang in your sourdough bread you have
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to ferment your dough for a longer period of time.
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Over time the bacteria will metabolize most of the
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ethanol created by the yeast in your dough. The bacteria
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mostly produces lactic and acetic acid. Lactic acid
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is chemically more sour than acetic acid but sometimes
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not achieved as sour. In most cases a longer fermentation
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is what you want. You will either need to utilize a loaf
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pan to make your dough or use a flour that can withstand
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a long fermentation period. A flour like this is typically
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called a {\it strong flour}. Stronger flours tend
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to be from wheat varieties that have be grown in more
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sunny conditions. Because of that stronger flours tend
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to be more expensive. For freestanding loaves I recommend
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to use a flour that contains at least 12 percent protein.
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Generally the more protein the longer you can ferment your dough.
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Another option to achieve a more sour flavor could be to
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use a starter that produces more acetic acid. Acetic acid
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bacteria tend to be more common in rye starters (source needed).
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Chemically the acetic acid isn't as sour, but when tasting
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it will seem more sour. Make sure to use a starter that is at
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a hydration of around 100 percent. Acetic acid production
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requires oxygen. A too liquid starter tends to favor lactic
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acid production because the flour is submerged in water, no
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oxygen can reach the fermentation after a while.
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\begin{figure}[!htb]
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\includegraphics[width=\textwidth]{parbaked-bread.jpg}
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\caption{A half-baked bread, known as "parbaked".}
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\label{fig:parbaked-bread}
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\end{figure}
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Another more easier option could be to bake your sourdough
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twice. I have observed this when shipping bread for my micro
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bakery. The idea was to bake my bread for around 30 minutes
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until it's sterilized, let it cool down and then ship it
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to customers. Once you receive it you just bake it again
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for another 20-30 minutes to achieve the desired crust and
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then you can eat it. Some of the customers reported a very sour
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tasting bread. After investigating a bit more it became
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crystal clear. By baking the bread twice you don't boil
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as much of the acid during the baking process. Water
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evaporates at around 100°C while acetic acid boils at
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118°C and lactic acid at 122°c. After baking for 30 minutes
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at around 230°C some of the water has started to evaporate,
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but not all the acid yet. If you were to continue to bake more
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and more of the acid would start to evaporate. Now if you were
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to stop baking after 30 minutes, you would typically have reached
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a core temperature of around 95°C. Your dough would need
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to be cooled down again to room temperature. The crust would
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still be quite pale. Then A couple of hours later you start
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to bake your dough again. Your crust would become nice and
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dark featuring delicious aroma. The aroma is coming from the
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maillard reaction. However the core of your dough still won't
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exceed the 118°C required to boil the acid. Overall your
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bread will be more sour. The enhanced acidity also helps
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to prevent pathogens from entering your bread. The bread
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will be good for a longer period of time. That's why
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the concept of a delivery works well with sour sourdough bread.
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In my experiments the bread stayed good for up to a week
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in a plastic bag.
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\section{My bread is too sour}
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Some people like the bread less sour as well. This
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is personal preference. To achieve a less sour bread
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you need to ferment for a shorter period of time.
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The yeast produces CO2 and ethanol. Both yeast and
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bacteria consume the sugars released by the amylase enzyme
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in your dough. When the sugar is rare bacteria starts to
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consume the leftover ethanol by the yeast. Over time more
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and more acidity is created making a more sour dough.
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Another angle at this would be to change the yeast/bacteria
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ratio of your sourdough. You can start the fermentation with
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more yeast and less bacteria. This way for the same given
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volume increase of your dough you will have less acidity.
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A really good trick is to make sure that you feed your starter
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once per day at room temperature. This way you shift
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the tides of your starter towards a better yeast fermentation \cite*{more+active+starter}.
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To shift the tides even further a real game changer
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to me has been to create a stiff sourdough starter. The
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stiff sourdough starter is at a hydration of around 50 percent.
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By doing so your sourdough starter will favor yeast
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activity a lot more. Your doughs will be more fluffy and will
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not as sour for a given volume increase. I tested this
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by putting condoms over different glas jars. I used
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the same amount of flour for each of the samples.
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I tested a regular starter, a liquid starter and a stiff
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starter. The stiff starter by far created the most CO2
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compared to the other starters. The balloons were inflated
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the most. \cite{stiff+starter}
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\section{Fixing a moldy sourdough starter}
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\section{My bread flattens out after shaping}
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\section{Liquid on top of my starter}
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\section{Why does my starter smell like acetone}
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\section{My crust becomes chewy} |