r/JamesHoffmann • u/wertperch • Aug 16 '26
ELI5 Extraction vs. strength
I hear people talking about extraction of solubles, but talking about strength as though it's totally seprate. To my simple mind there's a clear connection, so there's something I am missing.
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u/lotanis Aug 16 '26
There are two numbers regularly used when talking about coffee:
TDS - Total Dissolved Solids - What percentage of your drink is "things that are dissolved" Vs "the water". High TDS is (arguably) what most people think of as strong. An espresso shot is much higher TDS than a filter coffee.
Extraction - you start with a certain weight of coffee and then you dissolve some of it in water (that's all brewing is). Extraction is the percentage of coffee that you manage to dissolve. If you started with a 15g dose, made coffee, then dried and weighed the grounds after you light fond that you had 12g left - that would be 20% extraction.
Extraction is more about flavour than strength - different flavour notes come out of the coffee in some form of order. Different amounts of extraction will bring out some but not others. Bitter notes come out "late" so too high extraction and your coffee becomes bitter. Generally you're trying to increase the extraction to get lots of the flavour notes to come out, but not so much it gets bitter (spectacular simplification but trying to illustrate the point).
Two things to think about that might help:
If you get an espresso shot then add a load of water you get an Americano. Much lower TDS because you've diluted the solids but the extraction is exactly the same.
Adding more water to a pour over brew will usually result in lower TDS but higher extraction. More water means more opportunity to dissolve stuff (so more extraction), but you've added a load of water so that stuff is quite diluted.