Grind and Tamping

The grind and tamping go together hand-in-hand.  The idea is that the packing of the coffee grinds provides resistance for the heated water.  This resistance causes the water to flow slowly through the grinds and extracting the components of “espresso” at the coffee-water interface.  As well, this extraction pressure causes the gases (mostly carbon dioxide formed by roasting reactions) to pass into solution…forming the elusive crema–a sign of a good “pull.”

All other factors being equal, the finer the grind, the tighter the grains may be packed tighter.  Also, the harder you tamp, the tighter the grains of coffee are packed together.  These two variables together affect the amount of resistance afforded by the coffee against the heated water.

What you read about the grind from other sources is true.  It is VERY important and not to be overlooked.  Don’t even try using a blade coffee chopper.  They are fine for normal drip coffee and French press but a chopper will not give you the narrow range of grain sizes for espresso.  As well, if you manage to get one good grind with a chopper, it will be almost impossible to repeat it.  At least get yourself a lower-end conical burr grinder (the La Pavoni PG are supposed to be good, and the Bodum Antigua I’ve used with success).  Better still, get a dedicated espresso grinder (I now use a Gaggia MDF but like the Rancilio “Rocky” as well).

For my Gaggia MDF, the perfect grind is achieved at setting 5 or 6. The description of the proper grind range from grains that resemble sand to grains slightly coarser than flour.  My feeling is that these guidelines are too vague and can mean something different to each person.  That is, you can play around with the proper grind all day, but at this stage, it may be more effective to eliminate another variable and work on the tamp.  For now, simply go to the nearest grocery store and find yourself a can of ground Illy regular roast espresso (something that should be easy to find worldwide) and you’re in business!  You can always mess with the grind later.

Tamping is where I had my breakthrough.   In order to get any crema, it is amazing how hard you actually have to tamp.   I find that in order to produce an excellent shot, it was necessary to pack the 12 grams of coffee into the double portafilter with about 35 pounds of pressure. As you let off on the pressure, give the tamper a twist to polish off the top. The twisting also keeps any coffee from sticking to the bottom of your tamper. I tamp and polish twice. 

To practice, put your handle and portafilter with the coffee on top of a bathroom scale and press down.  Feel how hard this is for reference and practice, practice, practice!   With the proper amount of coffee and tamping, there should be about 3-5 mm of space between the grinds and the top of the portafilter.  If there isn’t, take a bit of coffee out or the handle won’t fit into the group head.  That being said, there are some La Pavoni users that grind finer and barely tamp.  After you master tamping the Illy pre-ground coffee, you can work on your own variation.

Next…

{ 6 comments… read them below or add one }

mschmidt July 20, 2011 at 05:16

When I tamp the coffee as hard as you describe, my machine stalls. I have to tamp very light with Illy ground coffee in order to get something through.

Mark October 30, 2011 at 11:43

I’m glad mschmidt has said that because I have had the same problem with Illy ground coffee. With most other brands I can or have to tamp quite hard like you suggest and that’s fine.
I’m not sure whether this is down to the finess of Illy’s grind or whether it contains more oils. It almost seems damp when it comes out of the bag the way it clumps together.

Szilard November 14, 2012 at 16:12

Hi Daniel,

THANK YOU FOR OPERATING THIS SITE!
I bought my Stradivari through internet, at first I almost sent it back (according to EU regulation you have opportunity sending back for 14 days in case of internet-purchase), but I’ve found your site 🙂
YES, secret of perfect shot are finesse of grind and srtength of stamp.
My experiences:
It is impossible to prepare accurate espresso with too rough grind. Do not stamp hard moreover not at all you use too fine grind, otherwise you have to pull lever again and again.

regards
Szilard

patrick August 28, 2013 at 01:42

What shld I do to kip my crema. Is it the tamp or does the roast affect the levl of crema as well. am using a medium dark roast blend of 70% fully washed arabic and 30%natural dried rubusta beans.

BaristaSai December 21, 2013 at 00:33

Can every barista (especially in sixth stage coffee) follow what your advice?

Chris Hall March 19, 2016 at 09:52

Do you really use 12 grams of grounds? That’s a lot.

Leave a Comment