Advanced Coffee Making talk

So who’s seen the video of Matt Perger’s recent talk in London?

I’m struggling to get on board with some of it… the fact remains that if I extract over a certain amount, it starts to taste bad. Extracting more doesn’t always seem to be a good thing. What am I missing?

It’s a long talk, is there a point we should fast forward to in order to put your question in context?

Guessing the issue is around “AIM FOR MORE” at roughly 52 minute mark.

Matt gives some recommendations that will help with extracting more, but the overall premise to “dial-in” is to over-extract and then dial “back” till it is not. Hence, extract more. Otherwise, most just stop at good enough which really can’t know, until you hit the limit of extraction.

“Extraction” though is sometimes treated as an absolute. A completely known quantity. From a certain perspective, it is. However, when balanced with subjective evaluations then this becomes a bit murky.

Meaning that it is very valid for flavorful coffee to have varying degrees of extraction that highlight specific flavor profiles that are what the coffee bean can best express.

Some coffee, no such thing exists. Personal story, I requested the pods of coffee from an American Airlines flight from the flight attendant to brew at home. These are the actual ones they use in their plane’s coffee torture/brewing devices.

There is no extraction on this planet or even neighboring parallel universes where this can be flavorful, as judged by any reasonably sentient species.

Top tier coffees from BH subscription generally have various optimizations for flavor profile extractions.

So, always better to extract as much as you can, but that is no guarantee at all of best flavor for that coffee.

So smaller grinds better, though water flow is problematic when too small due to micro-channeling, and also dosage size (bed depth) becomes a real problem at this point.

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I only got as far as 48min, now I can’t get back in. But by 48min, Matt was well into explaining his theory about sub 250um grinds fully extracting (though this wasn’t demonstrated). Nobody is brewing day to day with a 250um maximum particle size that is also the mode. This may one day be possible and less wastage, tastier drinks from smaller doses would be great in specialty (the economical aspect is already a norm in commodity).

Extraction is not an absolute, the earliest brew charts stated extraction (brew efficiency) was not a sign of quality (taste).

Paraphrasing, he said the smaller particles that get fully extracted are the tasty ones and the larger ones that are holding back on extraction are the problem. He posits that a cup where every particle is nearly fully extracted would taste good. He also says that for filter brewing, removing all particles above 500um would be a good idea.


Well, the sub 250 & sub 500 only hit 24% extraction, this isn’t out of the bounds of normal, there is a fair bit to go yet to get everything out (very difficult in a declining temperature steep). EDIT: The talk noted that the coffee used in this test was a very light roast, it’s possible that this was as far as this particular coffee might go, but averaged maximum extractions over a range of coffees would be higher than this.

So there’s no advice thus far to over-extract (that I can tell, feel free to correct me if that appears later in the talk).

But again, this is in context with Matt’s theoretical part of the talk, that it could be good to extract all particles to an even & and high level…if we had the grinder to do this & if we had a filtration method to provide a clean cup.

With drip, with normal grinders, sure, it is easy enough to extract too much from some coffees for an enjoyable cup & still be in the gold cup box. Whilst other coffees can push the upper range & still taste good (so there is a fair tolerance in extraction given a range of coffees) It’s also easy to not over-extract in the gold cup box, but suffer with excess silt in the cup, which will flatten off sweetness & clarity (for both drip & immersion).

At what point are you extracting too much in your own brews? If it’s under 17-18% (percolation), you’re probably not, more likely you have some other malfunction.

I don’t think anyone is saying, ‘extract the absolute maximum possible’ (with current grind technology & brewing practice). There may come a day when we can extract significantly more than we do now, on average. Nespresso, Rombouts & Ground Control, for example, already seem to be doing so.

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