USER MANUAL
Spirit User manual
page 7
The amount of water in the feed line from group-valve to coffee-bed should not vary.
When a brew is finished, excess pressure on the coffee-bed is released via the 3-way group valve at
the back of the coffee boiler neck. This line may or may not drain completely before a new shot is
started. To have initial conditions as identical as possible we recommend a short flush (2 seconds) just
before locking in the filter holder with new grinds such that conditions in the feed line before a brew is
started is always the same.
Flow rate during the entire brew may not fall outside the range of the flow meter.
At the start of a brew, when the coffee bed is dry, flow-rate in the coffee system is very high. Right
after the pre-infusion stage when the coffee is wetted and swollen up, flow-rate in the coffee system
drops dramatically, the more so with smaller grain-size and closer packing of the coffee-bed. As there
is no flow meter available that can accurately count volumes in a wide range from very slow to very
fast flow we install different flow meters for different preferred brews: 0.7mm aperture (3300 pulse/litre)
for short brews like ristrettos and espressos, 1.15mm aperture (2000 pulse/litre) for longer brews like
(double) lungos. A flow meter intended for short brews may not accurately count the volume of a long
brew and vice-versa. The flow meter is installed during assembly of the machine according to the wish
of the client but can be exchanged for another type later.
If brews are made with very fine and closely packed coffee grinds, the flow at the early stage of the
brew becomes so slow that volumes counted by the controller may still deviate from brew to brew
when the flow at any time during the brew becomes slower than 25 ml/minute (0.7mm flow meter) or
35 ml/minute (1.15mm flow meter) as the impeller in the flow meter will come to a stand-still or is
running too slowly. When an LED on the group starts flashing during the brew it is certain that the flow
is too slow but the blinking may hold off even when flow was too slow for accurate counting. When you
prefer to brew that slowly we advise to use scales under the cup in combination with manually (de-)
activating the group for best weight consistency in the cup.
