it's exactly one year since we uploaded
our very first video onto YouTube and so
I've asked um my colleague Dr Sam Tang
to bake us a cake in the lab to
celebrate she's going to make the cake
as far as she can out of chemicals and
using the sort of apparatus that we
normally use in the lab I I love making
cakes I really do enjoy making cakes I
love the smell I obviously love eating
them to start with making a cake you
need to cream together
the butter there are some things that I
just didn't have time to find the lab
based equivalents so I've had to cheat a
little here I'm
sorry you see cakes like everything else
you me are made out of
chemicals mostly chemicals made up of
carbon hydrogen oxygen and nitrogen
atoms with a few other ones put in as
well now normally when I'm doing this at
home I've got a lovely Kenwood chef and
that would whiz these together in a ma
of seconds um the equivalent we've got
here is an overhead mechanical stirer
away we go what we'll do is we'll lower
that a bit more so
it's so we've introduced the air but if
we didn't do anything about this all
that's going to happen is that the air
is going to escape so what we need to do
now is introduce the other non-lab based
ingredient so what we're going to do is
crack that so what the egg's going to do
is going to to provide uh scaffolding so
each of the bubbles which are surrounded
by a layer of fat are now going to be
surrounded by a layer of the the egg if
you've ever made a cake one of the
principal components is flour now
normally flour is mostly made up of a a
starch so in this case we've pre-weighed
out our starch now you may not know this
but different sorts of wheat produce
different proportions of protein
and
starch and if you want to make
bread which you NOS quite hard you have
a um flour that comes from a wheat that
has quite a lot of protein where cake
you want to be really nice and soft and
yummy has much less protein one of the
key things about a cake is that it's all
nice and sort of BL bubbly and soft and
the bubbles inside are caused by gas and
the gas is carbon
dioxide sodium hydrogen carbonate people
will know this as bicarbonate soda which
you can just get off a supermarket shelf
so bicarbonate
soda and in order to get that to produce
uh carbon dioxide it needs to react and
in order to react that's a base it needs
an acid and in this case we've got
tartaric acid the same is true in bread
because bread also has these holes which
are made by carbon dioxide but the way
you do it for bread and for cake are a
bit
different in bread you put in yeast
which is a living organism and the yeast
digests some of the ingredients of the
um dough the the mixture for making
bread and makes carbon dioxide which
causes the
bread physically to rise in the case of
a cake people aren't patient enough they
want to eat the cake so there you mix a
um salt of sodium that contains
carbonate ion or hydrocarbonate ion and
a weak acid like tartaric acid and these
react together in the cake and produce
carbon
dioxide during the the the baking and
the baking heating the cake is just a
way of promoting a whole series of
chemical reactions here's where actually
is is one of Martin students
supercritical water reaction rigs this
is the oven uh that we're going to be
using okay so what we're going to do is
actually turn it on so all it is is just
putting it on on on the main so as you
can see there there is no way that um
your home oven will heat up as quickly
as
this oh no I I've just realized pants
um what' you do when I smelt it I'm
really glad you asked me to smell it
because um I've gotten ingredient so
this stuff here is and it smells amazing
is vanillin so C8
h803 eight carbons eight hydrogens three
oxygens uh and the way in which they've
been arranged gives you this lovely
Aroma from it this is 100 G bottle and
I've got a tiny amount from it but that
will be enough
so done oh twist that open pop it on top
of the heating block now that I've
sealed that up got our timer so what
we're going to do
is time it for we'll say 25
minutes well I think that I and all the
um our team are really excited by the
first birthday we never imagined that
there were so many people who would be
excited by chemistry and would want to
watch our videos we really want to tell
you about chemistry and why we love it
and also to answer your questions
because chemistry is everywhere it's
important in all our lives and so I hope
you will watch and we look forward to
celebrating our second birthday next
year okay um let's see how well this
cake has cooked so it's going to be hot
so you might want to stand back a bit
when this oven door opens cuz I
will so we'll see how easy this comes
out oh look at that that's cake and you
can see there it feels like cake by
golly it smells really it smells good
enough to eat um but but we can't eat
this because you made it in the lab
there are loads of chemicals around oh
you'll find out in a moment it's got a
little bit of a chemical additive that
we've added just to see if we can
increase the the Sparkle and the color
of our
cake
woo I thought it was most unexpected and
like a real experiment you can never
predict the result