these last couple of weeks while i have been chafing at the bit i have tried to direct the energy into making a lot of espresso to isolate what steps in the process make a significant and consistent improvement to the quality of the extraction
my distilled wisdom reveals two primary factors –
1. i have been using the Compak E10 and i have transformed the quality of the grind and the distribution of it by simply putting a lot more coffee in the hopper – i.e. never less than 300g and topping it up with 2 x 250g bags. i would be most surprised if you do not see a similar improvement on all doserless conical burr grinders. so that was the first big improvement
2. we have all heard about the need to ‘seal around the edges of the puck’ but my work on preparing a lot more shots over the last few weeks has revealed that this step is really critical. dosing a central cone of coffee into the portafilter and then tamping severely impaired my results. dosing a central cone and then knocking it level with couple of sideways sweeps of the tamper is better, but still lacking. no, what is required is to take the new londinium button tamper and use that new sharp edge as you would if you were a ceramicist, paying careful attention to move the grains of coffee right in against the perimeter of the basket without so much as gap that is the width of a couple of grains of coffee between the last grain and the edge of the basket. that is where the dividend lies; in being meticulous in moving grains of coffee right hard up against the edge of the basket for the entire perimeter
then you tamp flat once with moderate pressure and finish with a twist of the wrist (polish if you prefer that term)
done.
try it and let me know how you get on in the owner’s forum. the last few weeks have shown me that these two steps have allowed me to consistently achieve near perfect central cone pours on the L1, shot after shot
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NB: if you have a flat burr grinder step one is less relevant as the fast rotation creates the centrifugal force to pull the beans into the burr and throw them outwards into the tapered gap between the two burrs. but a conical grinder absolutely must have a weight of beans on top to produce a decent grind in my view
if you dont want to use such a large amount of beans you might be able to use billiard balls or similar to add weight on top of the beans, but be sure to use something that is sufficiently large in diameter that it is unable to be drawn into the burrs. some sort of thawed gel chiller pack could work i suppose, but take care to ensure it cannot be drawn into the grinder or you will have a mess to clean up at best, and damage to the grinder in a worst case scenario