# Sour Coffee and Water Temperature



## salty (Mar 7, 2017)

I recently took delivery of the *Quindio Decaf from Crankhouse* and using the standard Aeropress guidance and brewing at 80-85c the resulting coffee was consistently sour despite changing grind, steep time etc. I contacted Dave, the owner of Crankouse to get his advice and he suspected that the coffee was being under-extracted due to low water temperature and referred me to the *Coffee Compass* on the Barista Hustle website. It's an interesting approach to identifying problems with coffee and potential solutions to correct them. As a starting point, the rule is that boiling water is always used and then the focus is on ratio/grind - just changing one thing at a time but always leaving water temperature the same.

So the first thing I did was try again using same grind/ratio but this time using water just off the boil. Bottom line is that it worked. Brewing at around 95c produced a non sour, rich balanced coffee and since then I've been tweaking other aspects - grind, steep time, agitation etc - to develop the brew, again using the compass as a guide and recording the method and results as I go along.

My question to Dave was why this coffee was producing sour coffee at 80-85c when I'd previously had good results with other beans at the same temperature. This was his reply:

"I'd agree - 80C is under extracting. If you go fine in order to increase solubility you can probably use the 80C that's recommended but all coffees will react differently. Decaf is a special case since it's already been heated prior to roasting (that's why it looks like I've roasted it heavy). It will behave vastly differently under the same brewing conditions as other coffee."

Apologies if this is all common knowledge - but thought it could be useful for other noobs like me.

Tim


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## kennyboy993 (Jan 23, 2017)

Great insight, thanks Tim.

I drink 90% decaf and hAve had similar problems with anything other than dark roasts so is good learning.

I'm wondering if decaf beans haven't been heated prior to roasting if they've gone through the Swiss water process?


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## salty (Mar 7, 2017)

kennyboy993 said:


> Great insight, thanks Tim.
> 
> I drink 90% decaf and hAve had similar problems with anything other than dark roasts so is good learning.
> 
> I'm wondering if decaf beans haven't been heated prior to roasting if they've gone through the Swiss water process?


That's an interesting point Kenny - could be. The only other decaf I've used in the aeropress, and with good results at 80-85c is Illy which according to their website - "is decaffeinated with the CO2 method, a process using two natural elements - water and carbon dioxide (sparkling water). This process is considered the safest method to decaffeinate coffee while maintaining its quality."

I wonder if that's the same case - i.e. haven't been heated during the decaf process?

Tim


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## Step21 (Oct 2, 2014)

Where does this "standard 80 - 85C" come from?

Light roasts and decaf will struggle at such low temps unless given loads of time to brew


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## salty (Mar 7, 2017)

Step21 said:


> Where does this "standard 80 - 85C" come from?
> 
> Light roasts and decaf will struggle at such low temps unless given loads of time to brew


Comes from the instructions shipped with aeropress


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## Step21 (Oct 2, 2014)

That's what I thought. This is the preferred method used by the inventor to make coffee he likes. It uses well developed caffienated coffee in large quantities with little water to produce a strong coffee which may be diluted.

Most AP users don't use this method or this type of coffee. There are possibly more "recipes" for the AP than any other brewer out there. Check out coffeegeek forum for a very very long thread to which the inventor contributes regularly.


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## MWJB (Feb 28, 2012)

@salty it's not really a standard, more one person's idea of a preference target for dark roasts. Adler has often said that light roasts are "sour", this is because methods like that under-extract them, probably dark roasts too, but dark roasts are less sour when under-extracted.

If you're going to steep coffee for a short while, without maintaining the slurry temp, you need very hot (close to boiling) water. Cooler temps will need more time and a maintained slurry temp (siphon), cooler temps with a declining temp (Aeropress) will always under-extract. This isn't a standard either, it's the unavoidable effect of the laws of the universe


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