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Pressure Profiling Espresso Extractions with the La Marzocco GS3

Did you know that changing the water pressure applied to the bed of coffee when making espresso can dramatically alter the taste? In this video Luke is using the La Marzocco GS3 and varying the pressure profiles to see how it changes the flavor of coffee. He extracts coffee using 3 bar, 6 bar and 9 bar pressure on the GS3 and analyses how it tastes in both milk and espresso style coffee.

In his experiment he discovers some interesting findings in his results.



Unedited Video Transcript

pressure profiling on the La Marzocco gs3
three bar six bar nine bar what does it
taste like
hang about and i'll show you my results
hey guys welcome back to the artistic
youtube channel thanks for joining us
i'm going to answer a few questions that
we've had over time about
pressure profiling and how does that
when you're looking at putting three bar
six bar or nine bar pressure on coffee
so i'm gonna run through a basic test
there are some parameters here that i'm
standardizing to ensure that
i give you i guess the best information
i can
that is streamlined and relevant rather
than going
really techie because there are so many
that you would change when you change
as opposed to the grind and the dose and
all of those other factors in there
including water temperatures so what i'm
going to do for this range of tests
is i'm going to do an espresso and a
milk based
for 3 bar 6 bar 9 bar
i'm going to record what they taste like
and as a standard i'm going to use the
same water temperature
being 92.5 degrees and we're going to
a 22.5 gram dose but we're going to keep
same grind setting
i'm not going to change coarseness or
when we go to a lower bar pressure or a
higher bar pressure
because that's a whole different world
so what i'm going to be assessing in
each cup
is the aroma the acidity the sweetness
the body
the finish and the overall flavor and
i'm just going to give that a score out
of 10.
so time to make some coffee
so i'm going to start by doing a three
bar extraction and then i'll go to six
and nine so i'm just weighing out the
grind getting a standard there
to 22.5 is what we're aiming for
across all of these 22.7
i'm pretty sure that will be
our standard moving forward
so we're just using our dosing pots here
it helps us move the
coffee from the scale straight in
just a little pre-distribution before
we're using an ocd
if you haven't used one of these before
it just levels out the coffee
and helps get a nice flat surface before
you go and tamp
we use flat tampers i really like the
space that that's creating before the
water comes onto that coffee puck
nice and flat and level and we're ready
to go
so we're going to be achieving um a one
to two ratio
so we've got 22 and a half grams coffee
so i'm going to get 22 and a half grams
out that left hand side
and that's going to be our standard for
our espresso base
for milk and for us to sample as
right so very close i got 22.1
so 0.4 gram i don't think we're going to
taste that
so i'll do up some milk
i'm going to keep that milk a little bit
cooler i'm going to leave it at 60
degrees i find
that's always a good temperature for me
to be able to taste milk
and coffee together and not be too hot
you can see not as much crema there in a
three bar
but it can be really surprising
the flavor you're going to get out of
all right let's go and taste it just in
my results if you can see on the paper
the blue is going to be my espresso
results and the milk is going to be
in black pen
all right let's go give the six bar
oh just need a fraction more on that one
great 22.7
so to explain what coffee that we're
using we're actually using our delicate
now this is our organic coffee
it's a three bean blend and it's roasted
medium light
so we're not trying to have something
here that's going to knock our socks off
or have huge bitterness
we are looking for a few more of those
subtle flavors
it's not a filter roast because that
would be a very different experiment
so this is closest to what we'd like in
an espresso roast
all right here we go again
okay straight up to six bar
so you can already see there's a lot
more crema that's coming out here with
that extra pressure
it's a faster extraction because of that
pressure as well
and bang on the money 22.5 or 22.6
so 0.1 of a gram out so
same results as the other one let's go
and taste it
bit of a floating heart there for you
just can't pick what that is
there's a really nice light fruit that's
coming through there and i just don't
have my
color wheel here to be able to pinpoint
what that flavor is
but i will try and put that in the notes
below afterwards guys
all right so let's go and try the nine
bar extraction and see what results we
now i know you're going to say something
about me picking out the coffee grinds
in my fingers
i'm drinking the coffee i don't have a
problem with it
but maybe use a teaspoon if somebody
else is going to be drinking this
all right this is the easy one just
straight up to nine bar
again a much richer color there at the
start that really dark colors which is
a lot of the sugars coming out with that
high heat and high pressure
22.2 all right so very very close again
we'll get some milk into this one
a lot more crema there just to be able
to pour into with our milk
so let's taste the nine bar pressure
so i want to put it out there i have
never done this with this coffee
and it's actually given me some really
interesting results because
i usually have one milk coffee in the
morning and then i drink black for the
of the day and i'm starting to see a few
things in my own palette
that make me change the way i want to
make my black coffee
and how i want to change for my milk
now i know what i've been doing on my
gs3 for a while
since being able to get the pressure
profiling in milk and i'm not going to
tell you what i do just yet
but these results are really a bit of an
eye opener
for you as a person to understand do i
like more body do i want more citrus to
want more acidity and hopefully these
will help you understand what kind of
coffee you're looking for
and whether pressure profiling is
something that's going to help you
so what i'm going to look at first is
your three bar
espresso i've rated that with a higher
aroma with a medium to high
acidity medium sweetness
and banks back in the middle there for
with quite a long finish that was coming
in my mouth and staying there
now that acidity was actually a positive
acidity so in espresso some people like
and others don't but i don't mind a
little bit of
a bit of zing and bit of zip there in
the flavors that were coming through
with citrus grape and
i'm saying like a toasted sort of flavor
just starting to make its way through
it almost ended up bit more like a bit
of a prune kind of
taste in there as well so
when we then go to look at the six bar
the aroma was a little bit higher just
by a fraction
um the acidity was higher again and i
found that was actually more a negative
that was happening in this coffee
the sweetness was actually a little bit
and the body was actually just a little
bit lower as well so there's a few
things as the pressure is being applied
it's starting to
change a bit of the chemicals and
reactions that are happening in that
the overall finish was a lot shorter
in that in the mouth feel and the taste
and what was lingering in my mouth
that actually had higher citrus that was
coming through
slight toasty notes they weren't as
and this toffee flavor just started to
come through so like probably a very
um caramel style toffee not that dark
toffee when people burn them and make
the little you know lollies out of them
when we look at the nine bar espresso i
the aroma um to be
the same as the three bar um the acidity
was just coming back a little bit
which was a bit of a positive um i think
because the sweetness in this
was coming up so it was a little bit
more balanced for me
the body was definitely higher out of
all of them
and the viscosity that was coming
through in the actual
liquid there was definitely that thicker
sort of syrupyness that was coming
through in that espresso
and to note we were getting a lot more
as we went from 6 bar up to 9 bar as
the finish was a little bit longer again
and i think that was actually quite a
positive it was a lot smoother there was
a couple of different little flavors
that were
making me trying to work out what i was
actually tasting as it sat in my mouth a
little bit longer
so i'm saying it's got a very balanced
full flavor at nine bar
and it started from a citrus and sort of
ended up around this nice dark
berry i couldn't really pick exactly but
maybe like a blackberry or something
like that
it's not into that stewed fruits sort of
area just yet
but you could generally get that in a
bit of a darker roast coffee than
this profile that we've got so overall
for me in espresso i ranked the 9 bar
espresso 9 out of ten
and i put the six bar at eight out of
and i put the three bar espresso at six
out of ten
so for me um i guess i've been drinking
espressos for a long time and they've
been that nine bar
pressure from start to finish i love
that body that syrupy that
thickness that really comes when you get
that higher pressure and the sugars are
coming out of the coffee
when i drink espresso myself i've got a
rule of drinking it in threes i drink
the top layer the middle
and then when i finish i just want that
thick syrupiness just to coat my teeth
and stay on my tongue
for ages so that's the kind of espresso
that i enjoy
and i think that's why that's happened
the results here so yeah
overall i'm enjoying that traditional
9 bar espresso all right so now let's go
have a look at
the milk-based coffees that we've had
the three bar milk coffee had
look i put a hot a medium aroma to be
honest for me when we put milk with any
sort of coffee
i really struggle to get an aroma that
comes out because
to me the dairy sweetness overrides it
and i'm not really getting anything from
that coffee to be honest so on all of
these i'd say the aroma for milk is is
the same
when we look at the acidity back in the
three bar
it's right in the middle it wasn't too
much or too little
it was it was just just enough there to
help cut through that dairy
the sweetness for me was just going up a
little bit
um i put that at about um about
70 on the scale and the finish was
long it sat around for a long time and
the body wasn't
overpowering it was definitely
from a flavor perspective a buttery
caramel and just
really smooth easy drinking coffee
that had quite a complexity that was
actually coming through
so i really did enjoy that that style of
when we look at the six bar extraction
the aroma
again pretty much the same the acidity
was just a little bit higher i found the
sweetness just to be
a little bit higher again probably
around that 65
the body was just starting to creep up
in this
in the milk so it wasn't uh overpowering
the milk but it was
just noticeable that there was an
intensity that was starting to come
through in that coffee
and the finish was actually just getting
a little bit shorter
so it was not hanging around in my mouth
as long
and i think the dairy was probably
overpowering so it's getting a bit of
that milk taste that sort of coats your
mouth after you've had a milk coffee
i'd say there was a very light fruit
that was coming through at the start
with a caramel and not quite toffee but
i'd probably even say caramel to sort of
raw sugar
sort of taste starting to come through
in that coffee
and in the nine bar the aroma again
just right down the middle the acidity
was a little bit
lower the sweetness was actually a
little bit lower
um the body was starting to come a bit
higher probably around 80 percent
um and the finish was just it just
stopped to be honest there was nothing
that was really
hanging around in my mouth it didn't
feel like i've i've drunk a coffee
but i felt like i'd had my flavor kick
but then it just disappeared it wasn't
going to hang around with me all morning
it was definitely a smooth cup good body
good balance a bit of hazelnut praline
a bit of a milk chocolate kind of flavor
that was coming through as well so
all round a very balanced cup with the
so i was quite happy with that when i'm
ranking these
out of coffees i put the three bar
as my top milk coffee i gave that a nine
out of ten
second was my nine bar extraction i gave
that an eight out of ten
and then six bar came in at seven
and i think that's because since having
this machine
i've been able to play a little bit with
that profile and the pressure
i seem to be heading in my own flavor
looking for that real buttery creamy um
smooth sort of coffee that that i'm
getting from this three bar extraction
at the moment
so that's what i'm enjoying and i know
that's pretty biased
and you know this test is how i taste
coffee and how i enjoy
coffee but hopefully gives you an idea
of what's going to happen when you do
start to play with pressure profiling
so guys i hope you've enjoyed that
little experiment
i hope you got a little bit out of it
and understanding of my flavor tastes
and what i enjoy about coffee and also
my palette
so if you've got any questions about
pressure profiling i'd love to hear more
um start this discussion down the bottom
in the comments
you know are you a nine bar are you a
six bar or a three bar kind of person
let us know let's let's dive deep into
and find out what there is to know more
about this topic
so that's definitely enough coffee for
me today i'm feeling a little bit buzzy
you know tasting six coffees and a
morning coffee this morning and it's
still early
so guys my word of warning is if you are
going to taste a bit of coffee make sure
you have some food have some water
because it can affect you for the rest
of the day thanks very much for watching
everyone have an awesome day
catch you soon


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