as baristas we like to think that our technique is what makes a difference we tell people that
making great coffee is a combination of art and science but is that really true with tamping today
we are going to find out we'll answer the most common questions that people have about tamping
and we'll run through some practical tips on how to get the best results with your coffee
hi my name is josh and i'm from the coffee science and education center now when i'm training
baristas on the fundamentals of making espresso a couple of questions about tamping keep coming
up they want to know how hard do i need to tamp does tamping level really matter now some people
say that you need to tamp really hard while others say the pressure doesn't matter all that much
now we don't want to make any assumptions so we put some lab coats on performed a series of tests
and got ourselves some data before we get into that i should clarify that we are not looking
into different techniques for distributing the coffee grounds that is an important topic and
we'll take a look at that next time today we are just focusing on the act of tamping itself
now for our first test we want to find out if tamping harder change the flow rate of
the espresso or if it improved the consistency from shot to shot to make sure our results were
consistent we use the Puqpress it is an automated tamping machine which tamps an exact pressure
every time we pulled a total of 25 shots of espresso 10 20 and 30 kilos of tamping pressure
and we averaged out the results we used three different styles of espresso blend for these tests
to make sure the origins and the roast profile weren't a factor the end result was that the
higher tamping pressure made no difference to the extraction the extraction times weren't longer
for the 30 kilo tamping nor were they shorter at the 10 kilo and they weren't any more consistent
from shot to shot they were exactly the same so if tamping harder doesn't make a difference
then what is the point of tamping at all well it's really about removing all the air pockets and
making sure the water moves evenly through the bed of coffee if water does find an easy opportunity
to work through one of these gaps this is what we call channeling we can see this happening if we
don't tamp the coffee at all you'll see holes in the bed of used coffee and the espresso will flow
more quickly and it will probably taste pretty nasty too so our goal here isn't to press down
hard it's more about providing a compact surface and to make sure that the water does its job
moving through that bed of coffee as evenly as possible now most barista trainers will be careful
to point out that you should always tamp level with the basket but we wanted to test if it had a
measurable effect to the flow and the consistency of our espresso shots when we don't get it right
unfortunately our robotic tamper only tamps level so we had to use some good old-fashioned
humans for these tests for this test we brewed a series of espresso shots using 10 degrees and
then another set at 20 degrees and we compared these espressos using a level tamp of the same
pressure to see how they would compare this time the differences were obvious straight away
the shots made using an angle tamp had a less consistent flow than the shots made with a
level tamp the used coffee also showed obvious signs of channeling and more importantly in our
blind taste tests the espresso made with the angle tamp just didn't taste as good
now the negative results were more obvious at 20 degrees than even at 10 degrees so the conclusion
is pretty obvious the more level you keep your tamping technique the better your coffee will be
now okay with our testing out of the way let's run through some practical side of tamping techniques
so that you can get consistent results with your coffee and so you don't end up with the repetitive
strain injury the rsi now the purpose of tamping is to firmly and evenly pack the coffee for
extraction with this in mind the quality of your movement and tamp is what we are looking for here
make sure you hold the tamp in such a way that it's not going to put any pressure on your wrist
for most people it's best to hold the tamp in your hand like a tennis racket or like a microphone if
that's more your thing now you want to wrap four fingers around the handle and place your thumb on
the base as support it's usually best not to hold the tamp like you're stamping a letter that is
just a recipe for disaster and a whole lot of pain down the track now if this feels uncomfortable
i'd also recommend this method as an option i like to put my fingertips to the edge of the tamp it's
where i'm touching the tamp and the edge of the basket while stamping this feel and my eyesight
on the connection of the tab to the basket really helps me know if i am tamping level and correctly
next i'd recommend that you rest the group handle against the corner of the bench try avoid using
the spouts because that is a recipe for damaging those or even picking up any loose grit that might
be on the bench and then transferring that to your cup of espresso via the extraction then i want you
to stand side on to the bench get your elbow up and this will ensure that your wrist is straight
and will cause you to engage your shoulder remember as we showed earlier you don't need a
lot of pressure just a gentle lean with your body enough pressure to crush a kiwi fruit is plenty
a couple of quick notes on technique some people feel they have to tap the handle after tamping to
loosen the coffee from the walls of the basket apart from damaging the tamp and the handle it
can create gaps at the point of impact which makes channeling more likely and certainly more obvious
at times if you really are concerned about the coffee stuck to the wall of the basket you can
also get a slightly larger tamp which fits more closely to the basket that you're using this will
make sure the coffee is tamped all the way to the edge right from the start also some people
add a twist to the tamp movement to polish the bed of coffee now to be fair this is unlikely to
cause any issues with your extraction but it's not an essential movement to make particularly
if you're making hundreds of coffees a day at the end of the day you want to tamp firmly until you
feel a good amount of resistance and call it a day another common tamping idea crops up often
in training sessions they say josh i could change my tamp to change my tamp pressure to increase or
decrease my shot times accordingly the root of the issue is that ambient conditions have caused your
coffee grind profiles to change so therefore it is best practice to adjust your grinder and stay on
recipe and to keep your tamping pressure as relatively consistent as you can that's our round
up on tamping technique now this is just a start on a series of videos looking into the details and
the science of espresso technique next time we are going to dive into the rabbit hole of distribution
do you really need a special tool or a certain technique to distribute the coffee before tamping
or are these just a waste of time so tell me in the comments what are your questions
around tamping i'd love to hear what you think and i'll see you guys next time