Hi class, welcome back to baking school. Now we are currently on lesson 9 of the
baking fundamentals course and today we are going to talk all about leavening.
Now if you've ever baked anything before you're probably somewhat familiar with
the concept of leavening but today I want to dive in deep into what leavening
actually is and all of the different ways our baked goods can be leavened. So
leavening refers to the gases that are trapped inside of our baked goods as
they are baked. Now this is what makes our baked goods rise what makes them
spread out and also what keeps things tender and fluffy. Now there are three
different categories of leavening used in baking: there is chemical leavening,
there is biological leavening, and there is physical leavening so let's review
each type and how it functions in baking. So first let's talk about our chemical
leavening agents and these are baking soda and baking powder. Now the way these
two things work is when they are added into our dough sand batters a chemical
reaction occurs that creates carbon dioxide gas.
Now this gas gets trapped in our baked goods and what makes them rise. Now there
is some differences between baking soda and baking powder. Now baking soda which
is also known as bicarbonate of soda or sodium bicarbonate is alkaline on the pH
scale so in order for it to work and have that chemical reaction it needs an
acidic ingredient to react with. So a few common ingredients used in baking that
are acidic include brown sugar, chocolate, buttermilk, molasses, and lemon juice. Now
baking powder is actually baking soda already combined with another acidic
ingredient so when baking powder is hydrated it already will begin reacting
and it can be used in any recipe because it does already have that acidic
ingredient present in it. Now baking soda and baking powder work very quickly, they
will begin producing that carbon dioxide gas almost immediately when they are
hydrated and so they need to be baked much immediately after they go into a
dough or a batter. Now I actually have a very detailed article on my website all
about baking soda and baking powder and how they function in baking so I'll
leave the link for that for you in case you're interested. Now moving on to our
next form of leavening which is yeast and this is considered a biological
leavening. Now the reason why we call this a biological leavening is because
it is actually a living organism. It is actually a fungus now the way yeast
works is it feeds on sugars and starches present in the doughs or batters it's
in and as it feeds it also produces that carbon dioxide gas as well as alcohol.
Now this process of the yeast feeding and producing gases is called
fermentation and it is what makes yeast dough's rise so in contrast to baking
soda and baking powder working very quickly to produce the carbon dioxide
gas. Yeast produces this gas very slowly and over a long period of time. So in
order for the dough to contain that gas it needs to have a lot of structure and
elasticity so this is why yeast dough is kneaded over a long period of time to
create that really strong and elastic gluten structure so that it contain
the gases that the yeast is producing. Now you can actually see this in
progress in this time-lapse video of my yeast dough rising. So what is happening
is the yeast is feeding, it is creating those gases and the dough is gaining
volume which is leavening the dough. Now this is called the fermentation process.
So the last type of leavening is physical leavening now this is the type
of leavening that happens just from air and steam. So air is used really
frequently in baking as leavening and you can most commonly see this by when
you cream butter and sugar together so this process of beating together solid
fat with sugar traps tiny little pockets of air in between the ingredients. Now
this pocket of air adds volume to our baked goods.
Now you can also see air being used as leavening when you beat egg whites into
a meringue or when you beat cream into whipped cream. Now steam is the other
form of physical leavening used. Now the way this works is ingredients such as
milk, butter, and eggs all contain water and that is going to evaporate in the
oven causing steam. Now this might not seem
quite as exciting as the chemical reaction that happens with baking soda
and baking powder but actually when water turns to steam it increases in
volume by 1,500 times so it can really produce a great deal of volume in our
baked goods. Now one of the best examples of how steam is used as leavening and
baking is with puff pastry the way puff pastry is made is with many alternating
layers of dough and butter so when that dough is baked all of the water that is
present in the butter is going to evaporate off which creates a great deal
of volume and puff to the puff pastry. Now another example of this is when
making a Dutch baby pancake so if you've ever made one before there is no
chemical leavening in it, no baking powder no baking soda but there is a
great deal of liquid in the batter. So when this batter hits a very hot oven
it's going to quickly evaporate off and you can see here the great amount of
puff that happens when this Dutch baby is baked.
So now that you understand all about how leavening works in baking I want to give
you your homework assignment so I'd really like for you to try making choux
pastry for this assignment. So if you've never made choux pastry before it is a
staple in baking because it can be used to make so many different things like
cream puffs, profiteroles, eclairs, French cruller, doughnuts and even a
french-style gnocchi. Now choux pastry is such a great example
of how powerful steam can be as leavening. If you've never made choux
pastry before I think you're really going to be surprised at how much volume
you are going to gain just from the water evaporating out of the dough as it
bakes. Now as always you can share your homework in a few different ways you can
share it in our private Facebook group where we continue the conversation after
every lesson you can also share it on any of your social media using the
hashtag #BBbakingschool or you can email it to me directly at Bettie@BakerBettie.com.
I'll see you guys next time.
Bye!