21
20
3.USING ESPRESSO EQUIPMENT
3.
It is important to fit the handle
correctly to a group head. When
fitted, the handle butts against a
sealing ring inside the head, and
the shower insert is just against
the coffee grounds. During opera-
tion, the whole assembly is under
considerable pressure (8 bar or
over 110psi).
If the seal between the handle and
the group head is too loose, water
can flow through the seal and out-
side the head. Furthermore, the
handle could release itself from
the head during the coffee making
process, with coffee grounds, boil-
ing water and cup going in all
directions. Clearly a dangerous sit-
uation!
The rubber seal in the head can
also become dislodged by coffee
grounds being forced behind the
seal. This will make it difficult to
work the handle, and means the
head needs to be disassembled
and cleaned by the service agent.
Fit handle
to group head
The filter basket rim fits against a rubber seal
in the group head. It’s important to make sure
the top of the basket is free of coffee grounds
to get a good seal, and to prevent damaging
the seal.
In this photo, the handle was not
correctly fitted to the group head.
This caused the handle to release
when the pressure increased,
causing a hazard to all.
Incorrect: handle not tight enough in head
Correct: handle firmly locked into position
The photos below show how
coffee cakes should look when
emptied from the handle.
Correctly filled handle should release cakes
that don’t break apart
3.USING ESPRESSO EQUIPMENT
Tamping compresses the coffee
grounds to give the correct flow of
water through the grounds.
Tamping is essential to obtain uni-
form and complete extraction of
coffee from the grounds. The flow
of water is determined by the
grind texture, the dose and the
amount of tamping. Generally the
dose is correctly set, so the water
flow is mainly determined by the
amount of tamping, and most
importantly, the fineness of the
grind. The following photos show
flow rates for coffee that has been
ground too coarsely, correctly and
too finely. The correct flow will
ensure the best tasting coffee.
The art of tamping
If the flow is too fast, the grounds
are too coarse or tamping is too
light. If the flow is too slow, the
grounds are too fine or tamping
too heavy. As already explained,
you might need to adjust the grind
texture. For details see page
12
.
But importantly, adjust the grind
adjusting wheel one notch at a time.
Adjusting the grind.
Before fitting the handle to the
group head, be sure to remove
any coffee grounds on the rim of
the filter basket. Otherwise you
won’t get a good seal, and a build
up of grounds around the seal
area can damage the seal.
Clean rim of filter basket
Flow too high
grounds too coarse
Flow correct
grounds correct
Flow too slow
grounds too fine
Single cup coffee cake
Two cup coffee cake
