Vibiemme Domobar Junior - Manual (Page 14)

26 27
Too slow
A slow pull can either go well over thirty seconds to get even just one ounce from a double basket, or
produce very little coffee after as much as twenty seconds or longer. Often this slow flow will be very
dark in color and extremely viscous- a sign of over-extraction.
Causes of a slow flow can include:
• Coffee ground too fine. Adjust the grinder one or two clicks (or settings) more coarse and try again.
• Worn or inaccurate grinder burrs. Old, worn grinder burrs or a low-quality grinder can create a lot of dust in
the grind. This dust migrates towards the bottom of the basket and clogs the small openings, dramatically
restricting the flow of water. This also results in a bitter beverage even under proper conditions.
• Low pump pressure. Although not likely, this can be caused by a improperly adjusted pressure relief valve.
• Clogged filter basket. If enough of the holes in the filter basket are clogged it can slow the flow
sufficiently to make proper extraction difficult or impossible. Wash the basket and examine it by holding
it up to a strong light source. If clogged, soak it overnight in espresso machine cleaner (See chapter 10).
If that does not correct the problem you can try using a pin to clean the holes. If that does not work,
replace the basket.
• Clogged shower screen. If the screen in the Grouphead is not cleaned regularly it can build up
deposits of coffee as well as hard water deposits that can clog it. If a clogged shower screen is suspected
try backflushing (see Chapter 13).
At the speed limit
A delicious, proper flow creates a double of about two ounces (or a single of about one ounce) in about twenty-
five seconds. It flows from the spouts like warm honey, slow and thick, and although the color may lighten a
bit as it nears the end, even at its lightest color it should be a rich, caramel tone The variables involved when
choosing a grind, dosing an amount of ground coffee, and tamping can create a wide range of possibilities. A
grind that is one step finer on your grinder can create a different taste if combined with a slightly smaller dose
of coffee. One step the other direction (coarser) and a harder tamp with a slightly fuller dose may be preferred
with the coffee you are using. Add all the other variables such as the age of the coffee, how it was roasted,
and various temperatures of the brew water and things can get quite complicated!
The best advice as you begin this journey is to work at getting all these variables as consistent as possible and
just change the grind to create the best espresso you can. As you improve your skills you may notice that as a
batch of coffee gets older you need to change the grind slightly. You may even notice that when the humidity
in the air changes you need a different grind. Don’t get locked into a set routine. If something is not right in the
taste of the coffee, don’t hesitate to modify your technique. Try a different grind. Change the dose. If nothing
seems to work, change the coffee. The art and science of making excellent espresso is the journey, enjoying
the beverage is the destination, and there are a lot of roads that will lead you to that delicious drink.
Remember that we are preparing a food product. The ultimate indicator of whether a pull is successful
or not is how it tastes.