The Underrated Skill of Tamping

Milk Frothing Guide

How to use a VN coffee filter

Once you have established the mechanical side of your espresso set up - a pump driven machine & a burr type coffee grinder - you still have a few skills to learn.  One common pitfall is to think that you can use the plastic tamper that comes with most espresso machines...  or even some kind of household object that will fit into your porta-filter.  A quality tamper offers consistency and fine tuning that can make or break your morning espresso.

Picking the right tamper size:

The important elements to a good tamp:

1)  A good tamper with a flat or slight convex tamp surface.  The tamping surface should be smooth, polished.  Over time you will  probably score the surface slightly and that should not effect your shots.

2)  Pre tamping leveling of grounds.  When you first fill your filter basket with grounds, you will have an uneven mound of coffee in the basket.  It will be higher than the rim in the center and lower on the sides - THIS IS BAD.  Each person develops their own method to get those grounds evenly distributed before tamping.  The best way to start out is to lengthen your CLEAN & DRY index finger  and use it as a sort of squeegee - gently moving the pile of grounds to and fro allowing overflow to fall on the counter, floor or... - your spouse going to love this! -  You should have even & flat yet uncompressed coffee grounds spread across the PF.  Avoid bumps or dips on the surface.

3)  Tamp pressure.  With some practice, you will find the right pressure to get consistently tamped pellets or pucks.  As a general rule your tamping pressure should be about 30 lbs of pressure. You can use a bathroom scale to get a feel for what 30 lbs. of pressure feels like.  Your personal best tamping pressure is going to depend on the type of beans you use and the fineness of grind you produce.  

4)  Even pressure & Level tamp.  By making the puck evenly pressurized and level with the rim of the porta-filter, the coffee will infuse equally.  This just takes practice.

Hold the porta-filter firmly with the spout rested on the counter- use a bar towel or you are going to ruin your counter top.  If you have a double spout this will be easy - a single spout is hard to balance.  Use your other hand to push down on the coffee grounds.  As the coffee compresses, keep the tamper as level on all sides as possible.  Note resistance from your grounds so you can adjust your next try.

Install your porta-filter and make your shot.

 

Now -Evaluate the following.

Shot time - a shot should take 20 to 30 seconds for 1.5 to 2 oz.

If your shot is fast you may need finer grind and/or harder tamp.
Too slow means you need to back off grind and/or tamp.

Crema - A good shot has thick auburn foam covering the shot.
If you have yellow or off white foam you may need finer grind and/or harder tamp.
Dark brown foam partially covering the shot - you may need to back off grind and/or tamp.

The puck:  surface - should be even without bubbles or fissures. A
light imprint of the diffusion screen is O.K. but avoid strong imprint
as this means that the coffee has not been able to expand.

The knocked puck - should be in one piece but not too hard.

Look for grounds in the bottom of your cup.  That means you have too fine of grind.

Look for dark oily stains on your filter basket.  That signifies your tamp is too hard.

Note the above and make adjustments.  You may find that you need to adjust
 grind, tamp or both.  It will take some experimentation.  

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