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- Hi everyone.
Welcome to the Ask Dr. Lin Show
where I answer questions that
hit BAKERpedia.com everyday.
I am Dr. Lin from BAKERpedia,
the internet's largest place
for technical baking information
and the only place you should go first
when you need all your technical questions
answered on the go.
What I do on this show is
to answer the questions
that are most important
to commercial bakers.
Yes, you know, when your
line is at 100 cuts a minute
and you're not meeting
specs on all three lines,
who has the time to do
an hour long research
on the internet?
Well, this is what this show is for.
Place any comments to the topics
that you're researching on BAKERpedia,
and if you're lucky, I will
answer them on this show.
Alright, I'm gonna focus
today's show on fermentation.
Today's show is sponsored by DIOSNA.
With their Wheatplant Compactline,
you can produce consistent
quality sourdough or pre-ferments
with gentle agitation and total control
over the entire process.
Learn more at DIOSNA.com today.
Today's show is about dough fermentation,
why, what, how?
Fermentation in baking is a process
by which yeasted dough rises,
developing volume and flavor.
It occurs when yeast or bacteria,
like the ones in sourdough,
converts the sugars like sucrose,
fructose, glucose, and
maltose present in the flour
into carbon dioxide and ethyl alcohol.
Together with a well developed dough,
carbon dioxide is trapped
within the gluten network
in the dough which
causes the dough to rise.
Fermentation produces the leavening action
which results in the light and
airy crumb in bread products.
Commercial dough fermentation may include
bulk fermentation or pre-ferments,
intermediate proofing, final
proofing, and oven spring.
Each stage, except for pre-ferments,
is a time where dough is allowed to sit
ranging from 15 minutes to five hours.
Go to our fermentation page
to find out more about this.
Yeast is a single cell microorganism
part of the fungus kingdom.
It promotes alcoholic
fermentation by feeding on sugars
making it an excellent leavener in baking.
Yeast has three main roles
in the fermentation process.
Yeast produces gas in the
form of carbon dioxide.
This is caused by the yeast feeding
on the fermentable sugars in the dough.
The carbon dioxide
creates gaseous expansion
in the dough within the protein matrix,
allowing it to increase in volume.
Dough maturation occurs
by the chemical reaction
of the yeast produced alcohols and acids
in the protein of the flour
and by the physical stretching
of the protein by carbon dioxide gas.
This results in the light,
airy physical structure
associated with yeast leavened products.
Lastly, it gives the
characteristic flavor in bread
and other yeast leavened products.
Activated by moisture and carbohydrates,
yeast is most active at 95
to 104 degrees Fahrenheit
or 35 to 40 degrees Celsius,
and it is inactivated at
140 degrees Fahrenheit,
which is 60 degrees Celsius.
Bulk fermentation is what
we call the sponge stage
where the flour, water, and yeast
are mixed together to sit for a while.
Bulk fermentation is very beneficial
to water absorption and gluten hydration
and the development of flavors.
That is why sponge and dough systems
are so much more easy to process
and have a deeper flavor to it.
In the United States,
pre-ferments are what we
call flour and liquid brews.
This method takes a little
of the flour, sugars,
and all the yeast to do a
little fermentation work
to get a bit of the flavors
and to get the system to
start fermenting first
before a no-time dough is mixed.
Bakers have asked me if
this system is beneficial.
I honestly don't think
it is really beneficial.
I just think it is a midpoint
between making an
expensive capex investment
on equipment for a sponge and dough system
and making a no-time dough
faster to process and ferment.
It is in the middle of these two systems.
That's it.
So when a baker decides
on which system to use,
usually the decision is
based on the pocketbook.
Personally, I dislike no-time doughs
because it doesn't provide the benefits
of sponge and doughs,
which are higher hydration,
faster mix times,
less wear and tear on the mixer,
less stressed doughs, and less
usage of dough conditioners.
Okay, back to fermentation.
The third kind of ferment
is intermediate proofing.
Intermediate proofing is the time gap
just after mixing and before sheeting.
This is the beginning of
the journey for the yeast,
so it is about the most
active time for the yeast.
The final dough mixing temperature
is so important for this period.
Recommended final dough temperatures
are about 80 degrees Fahrenheit,
or 27 degrees Celsius.
If you get hotter than this,
not only will you have more of the holes
because there is so much
active fermentation happening,
but also you'll get a more stressed dough
that cannot be sheeting
and molded properly.
Intermediate proofing temperatures
must be controlled carefully
for the look and internal
structure of the product.
I would like to say that the final proof
is like the middle child
with the oven and baking
being the first child.
It's just that it doesn't
get as much attention
as it needs to.
The final proof is the time
where the dough gets to totally
relax and flow and rise up.
Time, temperature, and humidity
are very important during this time.
Many bakers seem to ignore this,
and it can bring many
problems to the final product.
Things like wrinkling of the skin,
jimmy cutters, crow's feet,
and keyholes, you know?
So proper optimum proof must
be performed at the proofer.
Temperatures must be around
95 degrees Fahrenheit,
or 25 degrees Celsius,
relative humidity should be around 90%,
and proofing time should
be about 60 minutes.
Now, I know none of you follow this
because you're only worried
about your first child
which is the oven,
which is also the
bottleneck in most bakeries,
but that's this other
whole discussion altogether
for some other time.
So please stick to a basic
principle of final proof,
and you'll be surprised
of a quality end product.
Let's talk about the last
fermentation journey of the dough,
the oven spring.
A little known fact is
that your bread product
can still be fermenting up
to 50% of the baking time.
So if it's a 20 minute baking time,
10 minutes of that time you're
bread is still fermenting.
Yeah!
Well, because why?
Yeast gets killed at about
140 degrees Fahrenheit.
The total temperature of the bread
just doesn't get to that temp
until almost 50% of your bake time.
Want to learn more about this?
Go to our thermal profiling page,
and you get to read
more about oven spring.
Let me really clear.
Oven spring is the worst way
to get your product to the spec height.
Do not use oven spring.
Always always always
depend on the final proof
to get you to your final height.
Why?
Because what goes up in the oven spring
always comes down in cooling.
In most cases, if you
depend on oven spring
for your final height,
you will likely find
issues with collapsing
and keyhole-ing of your product.
Whereas, if you depend on the proofer
to get you to your desired height,
you will not be expecting
collapse and keyholes
to be an issue.
So let's keep oven spring short and sweet,
and use the thermal
profiling method please
to control oven spring.
Now that we've covered the
basics of fermentation,
let's look back at the yeast.
In commercial baking, three types of yeast
are cream yeast, compressed
yeast, and dry yeast.
In cream yeast, yeast cells
are suspended in liquid.
This kind is used most frequently
in industrial high-speed bakeries
because they fit many tank
and dispensing solutions.
They are about 15 to 20% in total solids.
For compressed yeast, this is cream yeast
with most of the liquid taken out.
Also known as cake yeast,
it is about 30 to 34% total solids.
For dry yeast, it is the most common yeast
to non-commercial bakers and
bakers who are scaling up.
It needs to be rehydrated before use
and reacts slower than compressed yeast.
It has the highest total
solids at about 99%.
If you're thinking about converting
from one form to another,
go to our yeast spec page
and check out the total
solids table on there.
Use the total solids for your calculation
to convert from one form
of yeast to another.
That would be a great place to start.
Rapid rise is also commonly
known as instant dry yeast.
These contain more live
cells than active dry yeast.
While active dry yeast needs rehydrating,
rapid rise or instant dry yeast don't.
They go capow
(laughs)
when moisture touches them.
So rapid rise is kinda on steroids
'cause it produced more carbon dioxide
and it results in a faster proofing.
By the way, it's also the
most expensive form of yeast.
Remember that time and temperature
are the main controls for
fermenting and proofing.
The lower the temperature,
the longer the time and vice versa.
I'm sorry I do not have the perfect answer
for you on this question.
But it really depends on your
dough size, your spec height,
and the ability to proof for
a certain amount of time,
and this is usually dictated
by the oven bottleneck.
For starters, not knowing
your dough weight,
I would suggest to start
at 90 degrees Fahrenheit,
or 32 degrees Celsius,
and 90% relative humidity.
Proof to your desired height,
that is if your final
bake height is 12 cm,
proof it to 12 cm.
Because remember, whatever
height you get in the oven
should come off after cooling.
And if you're height doesn't
come off after cooling,
that means you used too
much yeast and gluten.
So again, use the 90/90 rule,
90 degrees Fahrenheit
at 90% relative humidity
until you meet your height.
This is a very common
question, believe it or not.
Go to our page for a
comparison of dough systems
and see how we did a comparison.
We did a thorough analysis
and placed the results
side by side to each other
so that you can have a bird's
eye view of the systems.
Personally, if you have an
interest in a clean system
with less dough conditioners
and a richer aroma,
I would suggest looking into
a sponge and dough system.
Because really, fermentation and hydration
provides a more relaxed dough
that needs less conditioners.
Also, I know sponge and dough
is going to be a little more expensive,
but the ROI, or return on investment,
on such a system with higher
absorption and lower mix times
will be quick if you think about it.
If you need more information about this,
you can buy our e-book on this topic.
We will also be talking about
the individual dough systems
in our next few videos.
That's all for today's session.
Thank you for joining
me today on Ask Dr. Lin.
Remember, BAKERpedia can't
be free without our sponsors.
This session is sponsored by
DIOSNA, the dough experts.
Check out their continuous
pre-dough production system
that is process controlled and optimized
for a consistent pre-dough quality.
So, if you want to make a
really really good pre-ferment,
go to DIOSNA.com today.
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See you next time.
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