# Over-extraction



## MikeHag (Mar 13, 2011)

I was re-read some pdf docs on my computer and thought I'd throw this extract up here from this article by Ernesto Illy. Sure, his 'optimal 30 seconds' isup for debate, but it's a great little read.


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## Milesy (Mar 8, 2012)

Thanks for this


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## maarten_booij (Jan 28, 2011)

seems like there is not a very significant difference in the positive aroma's between a 20 sec vs 30 sec extraction, although the negatives are much less...interesting


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## MikeHag (Mar 13, 2011)

Sorry Maarten. How do you mean? By my interpretation a 20s shot has a much lower score for Rancid and Smoke flavours than a 30s shot.

Oh... I see. It's because of that 'optimal' line Illy put in there.


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## garydyke1 (Mar 9, 2011)

Surely the 'optimal' line would vary if you adjusted the grind and/or extraction temp and/or pressure and/or bean density ?

Or is the graph an average of all parameters and multiple data inputs?


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## fatboyslim (Sep 29, 2011)

Must be an average and/or be making a huge number of assumptions (correct grind size etc).


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## MikeHag (Mar 13, 2011)

I havent read the article lately but as it's written by one of the Illy family it may well be based on the Illy blend and their ideal brew parameters


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## jimbow (Oct 13, 2011)

It looks like the timings are those observed by Illy during his sampled extraction and so are perhaps meant to be relative rather than absolute. This suggests that 30 seconds was optimal for the extraction graphed but this time will vary according to brew parameters.


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## maarten_booij (Jan 28, 2011)

MikeHag said:


> Sorry Maarten. How do you mean? By my interpretation a 20s shot has a much lower score for Rancid and Smoke flavours than a 30s shot.
> 
> Oh... I see. It's because of that 'optimal' line Illy put in there.


Yeah, that's exactly what I meant. There is barely any difference in the positive aromas, while there is a significant increase in negative aromas.


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## hyperactivemind (Mar 1, 2012)

fatboyslim said:


> Must be an average and/or be making a huge number of assumptions (correct grind size etc).


Exactly. You can't really factor in how hard you tamp and the size of the grind, which are all very important variables to take into consideration!


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