I came up with an idea today, potentially stupid, most likely not the first to have the same idea. After seeing a few posts online recently with people complaining about under extracted shots I noticed that one common response is down dose and grind finer….
I started thinking about what’s going on with coffee particle size when you do this and relating it back to Matt Perger’s excellent graphs here.
My slightly more amateur conclusion was that as you tighten the grind, that the total particle distribution would decrease and the percentage difference between the smallest and largest particles would be less, potentially a good thing for espresso (as per Matt’s EK43 posts) The fines aren’t going to get much smaller than they already are but the boulders will be closer in size to the average particle size in the basket. All of this should result in a much more even extraction and a great tasting espresso.
After work today I came home and fired up my K10 grinder to start putting this to the test and see how far it was possible to push the limits. This is still work in progress but the results so far a really encouraging.
I started out with my standard VST 20g basket that I usually dose up to 21g (for no other reason than that seems to be what many people do especially in WBC). I’m fully aware of the VST basket recommendations for up/down dosing of +-1g i.e. 19-21g in my basket, however for this experiment I wanted the coffee dose and grind only to restrict the flow the idea being that I can simply tighten the grind and decrease the dose to compensate.
I tightened up the grind significantly and decided to start at 18g, pulled a shot which took around 25 seconds to produce around 30g of beverage. The shot wasn’t too bad, nice body and pretty rounded flavours.
I tightened up the grind again and ran another shot at 17g which took almost 50 seconds to produce a 20g shot. I took a tiny sip, not as bad as expected but not great.
Keeping the grind the same I knocked the dose down to 16g (still in the 20g VST) and this produced a shot of 30g in 45 seconds… I decided to taste and there was the tiniest hint bitterness but on the whole the shot was really thick, well balanced and tasty!
Much more testing to do but things are looking promising, roll on this weekend!