# brewing compass coffee, extraction vs strength



## TheHToad (Sep 1, 2018)

Hi, I just sort of want clarification regarding strength vs extraction. This is what I know, so correct me if I'm wrong.

When using a v60
So extraction is the amount of soluble that is extracted from the coffee bean, and extraction can be increased by submerging the beans longer, which could be done if you use more water when brewing in a v60, e.g. using a 1:17 instead of a 1:15 ratio. However, the trade off is that you would get a coffee that is lower in strength. If this is correct, does this not contradict what the coffee compass says?

For those that do not know, this is the brewed coffee compass
https://baristahustle.com/blog/the-coffee-compass/


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## MWJB (Feb 28, 2012)

The 1:17 coffee is only lower in strength at the same extraction as the 1:15 brew.

To simply extract more, you grind finer and/or pass more water through the bed (submerging for longer is a bit irrelevant, there are ways to grind & stretch out brew time and get a lower extraction). Usually, if you're under-extracting & want to eke it up for a given ratio/recipe, you would just grind finer (not use more water unless you were trying to tame the strength specifically).

Look at it this way:

1:17 is 10g dose to 170g water. a 20% extraction is 2g dissolved into the beverage. Let's say you lose 20g of brew water to absorption that 2g dissolved is 2/150g = 1.33%TDS

1:15 is 10g dose to 150g water. a 20% extraction is 2g dissolved into the beverage. Let's say you lose 20g of brew water to absorption that 2g dissolved is 2/130g = 1.54%TDS

But, if you hit a very high extraction at 1:17 you could still have a beverage of 1.54%TDS as 150*0.0154= 2.31 or a 23% extraction. This could easily be the difference between 2 coffees of different origins brewed at the same recipe (same grind, same pour regime).


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