Tamping (for espresso machines)
A tamper is a tool that will improve the extraction process dramatically.  Applying 15kg of pressure to the coffee dose via a tamper restricts the flow of water pressure through the filter basket; giving the perfectly timed extractions – 30mls in approx 25 seconds.

Espresso coffee must be packed into a filter basket firmly with a polish. Otherwise, the pressurised water will break the coffee apart during the brewing process, affecting the outcome.  The tamper should fit correctly into the filter basket with no more than 1mm of space left inside the rim. 

When the group handle is locked in to the coffee machine, the coffee should not be touching the shower screen but have a minimal gap to allow expansion once the water flows through. 

There are many tampers on the market.  The handle design of your tamper is very important.  It should fit snugly into the palm of your hand, allowing full control with your thumb and index finger on either side of the tamper base so you can apply even pressure when tamping.  Many of the tampers that are supplied with domestic machines are not designed to give the same good results you will get from a well-made, metal tamper.  Tampers vary I weight and diameter, depending on the type of coffee machines they are used for.

Tips for Tamping Coffee

• Make sure the filter basket is filled with the correct amount of ground coffee.
• Brush excess coffee off, making the coffee level with the top of filter basket. Clear excess coffee from ring of basket.
• Place the filter handle on the bench, holding it level.
• Use tamper,  press straight down on ground coffee with approx 15kg of pressure (practise!).
• Spin tamper in circular motion to polish packed coffee leaving a flat, level surface for even water distribution.
• Check that the packed coffee is clear of any excess coffee from filter basket rim. The group handle is now ready to insert into the group head. 

Troubleshooting:
If the coffee is running through quicker than 30ml in approx 25 seconds you may be tamping too softly.  Also check that you are filling the basket with the correct amount of coffee.  There is usually a line on the basket showing where the tamped coffee should fill to.  If this is ok, then check your grind as it may be too coarse and therefore letting the water flow through the grinds too quickly.

If the coffee is not running through fast enough, you may be tamping too hard, have the basket too full or your grind may be too fine.
With a little practice and adjustment to your methods you will soon have the perfect coffee!