Vibiemme Domobar Junior - Manual (Page 11)

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9.7. Bitter coffee can come from:
• Water that is too hot
• Coffee that is over-roasted or stale
• Cheap, low-quality coffee
• Worn burrs or low-quality grinder that makes too much dust
• Brew pressure that is too high
• Not using enough coffee in the portafilter.
9.8. Sour tastes can come from:
• Brewing temperature that is too cold
• Coffee that is under roasted
• Brew pressure that is too low
• Bad or spoiled coffee
• The brew pressure gauge acts erratically*
*The Brew Pressure Gauge on the front panel should only be used as a general indicator as to what is happening
during the brewing cycle. The only time when the gauge will display any useful information is when there is a properly
prepared portafilter, filled with properly ground and tamped coffee, locked in the Grouphead, and the brewing process
is underway. At all other times, even when the pump is refilling the boiler, this gauge is not displaying any useful
information and should be ignored. Even when the pull is underway the brew gauge will read a little higher than the
actual brew pressure at the coffee. If all is going well, the gauge should read about 9.5 to 10 BAR during most of the pull.
10. Cleaning and Maintenance
As with all fine tools, the Vibiemme Domobar espresso machines can give you years of trouble-free
service and better performance if properly maintained. Your Vibiemme Domobar espresso machines does
require a bit of care, but it is not at all difficult.
Although the following guidelines will give you some idea of how often the tasks should be performed,
there is no specific set of rules concerning the frequency of cleaning and maintenance. A machine that is
being used to make two or three drinks each day in a home environment will not need to be cleaned quite
as often as a machine used in an office or restaurant where it is called upon to make fifty drinks a day. If in
doubt, it is better to do cleaning and maintenance chores a little too often rather than not often enough.
10.1. After Each Pull
KNOCK PUCK After the pull the spent coffee puck in the Portafilter should be knocked out. The best
way is to use a knock box. These feature a cushioned bar with a soft surface that protects the Portafilter
from damage.
QUICK FLUSH As soon as you remove the Portafilter from the Grouphead after a pull, cycle the brew
function for about one second or so. This will help flush out any coffee on or behind the shower screen.
FLUSH PORTAFILTER If you are not immediately going to pull another shot, replace the Portafilter
and repeat the quick flush. Pushing a bit of clean water through the Portafilter will remove most of the
left-over coffee in the Portafilter. Remove and wipe it off after the flush. If the machine is going to be
left on, leave the Portafilter in place so that it can remain warm.
10.2. After each stratching milk
The steam wand must be wiped off immediately after every use with a damp towel or dish rag after
removing the wand from the milk. As soon as the wand is wiped, the steam valve should be briefly
opened and closed to create a blast of steam to force out the remaining milk that may be in the wand.
Allowing milk to sit on (or in) the wand will bake the milk onto the hot metal. This is not only unsanitary
but can also become very difficult to remove. If you do have baked on milk we do not recommend soaking