# Temperature for brewed coffee, confusion and conflictions



## Zephyp (Mar 1, 2017)

After 4-5 years in the scene of third wave -or specialty- coffee, temperature is something I've never understood. I'm talking about brewed coffee in general, but my experience comes from Aeropress, V60, Kalita and automatic drippers.

There are generally two different camps on this subject.

1: Those that always use water off boil.

2. Those that change temperature depending on roast, taste, or at least use a lower temperature than off boil.

On various forums you will find many who claim they must use temperature lower than boil or else they'll get an overly bitter brew. Many also claim to have tried water off boil through a range of grind settings and not finding better results. One of my thoughts has been that those finding a positive difference between 100C and 95C might be overextracting at 100C and could have achieved the same by lowering extraction other ways, but I don't know if that's probable.

Another typical finding is that many use lower temperatures for dark roasts than they do for light roasts.

With the Aeropress, many recipes calls for temperatures down towards 80C.

Then there's automatic drippers. A Moccamaster delivers temperatures between 91-96C. As I understand, that's the temperature that comes out of the showerhead. This of course means the temperature in the slurry is lower. A Wilfa Svart Precision claims to have a temperature of 94C.

SCAA says: "Coffee Preparation Temperature: To achieve the Golden Cup Standard,

water temperature, at the point of contact with coffee, is recommended

to fall between 200°F ± 5° (93.0°C ± 3°)".

I interpret "at the point of contact" as the temperature of the water just before it hits the grounds.

Where does this conflict come from? Is it just personal preferences, where some enjoy the coffee brewed with a different temperature than others? Roast differences across the world? Water differences? Differences in beans? Brew methods?

If the golden cup standard is 93C and all automatic drippers use temperature in that area, why do some get better, or at least as good cups with water off boil? Using water off boil is of course very practical since you don't need to measure anything and can use any old kettle, but I wouldn't expect those using water off boil to drink overly bitter coffee all the time for the sake of convenience.

Would love to hear your thoughts.


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## MWJB (Feb 28, 2012)

There's no conflict. There's just what you need to hit a given result.

No brewer has a precise temperature to the degree, it's a range.

When any of the auto drip brewers are evaluated by SCAA or ECBC, the temp is the temp at the top of the bed/slurry, not exiting the shower head.

The CBI determined originally that you could brew coffee anywhere between serving temp and boiling. Lower temps are perhaps more feasible for immersions, as for drip you have a limited amount of time you can keep the water & coffee in contact.

80c Aeropress brews will always be under-extracted, you just might be able to hit a little peak of desirable flavour at a low extraction & will need to updose to bolster concentration. To normally extract coffee at 80C, you need to maintain that 80C, when the CBI taked about brewing temp, they meant slurry temp & allowed for a temperature drop when coffee was added & pulled down the water temp. Rao also discusses this in one of his books.

A ceramic cupping bowl, with 12g of coffee 200g of boiling water will likely never exceed 90C by the time water & coffee are combined, even if the kettle clicks off boil at pour.

If I bloom with boiling water & make a single mug, the slurry isn't likely to be over late 80's at end of brew. The water in contact with the coffee never was at boiling.

I think that most of these folk playing with temperature for pourover are not measuring & correlating against extraction. If you want a lower extraction you can use lower temp water, or you can gind coarser, or both. You're not going to brew with 80C water & get a gold cup drip brew. Dark roasts are often not great as drip, so I can understand maybe under-extracting to liven them up, but I've brewed with Illy for example, it doesn't extract significantly differently to my usual light filter roasts.

It's easier to be consistent by not twiddling with water temp.


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## Zephyp (Mar 1, 2017)

MWJB said:


> There's no conflict. There's just what you need to hit a given result.


By conflict I meant the general recommendations versus people using lower water temperature to achieve better results. If a 91-95C slurry is the ideal, you can't start by pouring 95C water.



MWJB said:


> When any of the auto drip brewers are evaluated by SCAA or ECBC, the temp is the temp at the top of the bed/slurry, not exiting the shower head.


Aha. I tried to figure that out about a Moccamaster, but could only find "heats the water up to the ideal 195-205F". My head interprets that as the water having that range once warmed up, but they probably mean the water in the slurry.



MWJB said:


> A ceramic cupping bowl, with 12g of coffee 200g of boiling water will likely never exceed 90C by the time water & coffee are combined, even if the kettle clicks off boil at pour.
> 
> If I bloom with boiling water & make a single mug, the slurry isn't likely to be over late 80's at end of brew. The water in contact with the coffee never was at boiling.


Agreed. I tried this a while back to see what the actual slurry temp was.

Temperature was measured in the slurry of a V60 with a Thermapen.

Bloom: 50ml, temperature 88C/190F

2nd pour: 150ml @ 0:30, temperature 91-92C/196-198F

3rd pour: 230ml @ 1:00, temperature 91C/196F

4th pour: 300ml @ 1:30, temperature 87-89C/190-192F

Finished brew @ 2:30

As the final water ran through the temperature dropped down to 80C/176F. I did not reheat the water in the kettle and it came straight off boil. It's a simple non-electric metal kettle without any insulation used on the stove. An electric kettle might keep the temperature slightly better with some residual heat in the element.



MWJB said:


> I think that most of these folk playing with temperature for pourover are not measuring & correlating against extraction. If you want a lower extraction you can use lower temp water, or you can gind coarser, or both. You're not going to brew with 80C water & get a gold cup drip brew. Dark roasts are often not great as drip, so I can understand maybe under-extracting to liven them up, but I've brewed with Illy for example, it doesn't extract significantly differently to my usual light filter roasts.


Haven't seen too many mention something as low as 80C, but many says they use water at 90-95C and never go higher since it makes the brew bitter. If coffee in it's very simplicity is just extraction and how much stuff you get in the cup, it never made much sense to me that a cup brewed with 5ºC colder water would achieve anything in the cup that you couldn't also achieve through other means to lower extraction. Usually coarser grind or different pour regime to shorten down brew time.

It may just be coincidences and results of the Internet as a source of information. When enough people do something with success, more will attempt it and even more will find success since their brews were coincidentally overextracted and the lower temperature fixed it. Same thing with recipes. I often come across people trying a new recipe and suddenly make great coffee. I interpret that as their variables happening to fit that recipe for great results and not that the recipe in itself is anything special.



MWJB said:


> It's easier to be consistent by not twiddling with water temp.


Absolutely. Which is why I'm always puzzled by the people using lower temperatures. Many having made thousands of cups. Why would they fiddle with water temperature if the same effect can be achieved in some other way?

One thing I have pondered is that temperature can be used as a means to change extraction if you don't want to change anything else. I don't know what would give more consistent results: changing water temperature a few degrees, changing grind or changing pour regime. I can see an advantage in keeping pour regime constant since you can change the brew time a lot just by how you pour. Some might consider changing water temperature with a kettle with a decent thermometer to be more consistent than changing grind or pour regime.


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## Batian (Oct 23, 2017)

What about the effect of altitude?

Living in Wales, the OP will find water boils at 96.5deg C on the top of Mt Snowden but at 100deg C in Swansea......

With such temperature precision required in the brew, altitude differences of even 2000' must start to become significant?


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## MWJB (Feb 28, 2012)

Zephyp said:


> One thing I have pondered is that temperature can be used as a means to change extraction if you don't want to change anything else. I don't know what would give more consistent results: changing water temperature a few degrees, changing grind or changing pour regime. I can see an advantage in keeping pour regime constant since you can change the brew time a lot just by how you pour. Some might consider changing water temperature with a kettle with a decent thermometer to be more consistent than changing grind or pour regime.


Assuming your water is boiling recently boiled, maybe over 90c (assuming for drip, you are not aiming to brew with a bizarrely low temp in the kettle), the difference in extraction probably isn't going to be a big swing.

Changing pour regime - massive swing, maybe +/-4% EY?

Changing grind - massive swing +/- 5%EY.


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## MWJB (Feb 28, 2012)

Batian said:


> What about the effect of altitude?
> 
> Living in Wales, the OP will find water boils at 96.5deg C on the top of Mt Snowden but at 100deg C in Swansea......
> 
> With such temperature precision required in the brew, altitude differences of even 2000' must start to become significant?


Not really, assuming you have an adjustable grinder & you can persuade your wrist to tip the kettle a little more often during a brew


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## jymbob (Aug 24, 2017)

Reading with interest. I've often been told that boiling water "scalds/burns the coffee" so habitually pour at 90°C (a setting on my kettle).

Is this an urban myth then?


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## Mrboots2u (May 10, 2013)

jymbob said:


> Reading with interest. I've often been told that boiling water "scalds/burns the coffee" so habitually pour at 90°C (a setting on my kettle).
> 
> Is this an urban myth then?


Yes.

It's unlikely that you are ever pouring boiling water onto the beans even at the start of a pour.

Remember that water added to a slurry will not be 90c or boiling , it will be lower that .


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## Zephyp (Mar 1, 2017)

A couple of fresh examples of someone finding their best cups when dropping the temperature:


__
https://www.reddit.com/r/Coffee/comments/bafq6q


__
https://www.reddit.com/r/Coffee/comments/ar2f7r

Would be awfully interesting to have them try lower extraction with other means and check with a refractometer.


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## Mrboots2u (May 10, 2013)

Zephyp said:


> A couple of fresh examples of someone finding their best cups when dropping the temperature:
> 
> 
> __
> ...


If they like it all good.

temp is simply another variable to help drive extraction in different directions , along with grind, dose, etc.

It's hard to know from those posts if they are manipulating extraction through temp and balancing it out with another variable ( grind etc ) or what there grinder is doing ....

Personally I find it easier to keep temp roughly where I know it is , same for espresso.

Brewers cup etc will always come up with a new temp, method etc. You c=find it har

I wonder if the people testing them , drink filter straight from the brewer or let it cool to room temp too. Hot coffee tastes different ...

Lastly some people will prefer coffee at lower extractions (coffee, roast dependent ) and that's all good.

I don't think brewing at 80-90c is some new kind of coffee nirvana, just a different way of getting to where some people find tasty.

If people are brewing at 80c it will be a lower extraction than your 18-20, I don't need a vst to tell me that, Again it a person likes it, or finds it "different enough" then its ok.


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## Zephyp (Mar 1, 2017)

Everyone can't enjoy the same tastes, that's fine. What's bugged me is everyone claiming that lower water temperature produces a better cup than they could achieve with adjusting any of the other variables. That is of course just their experience and not something most spent any time to investigate. And I can't say that they are wrong, of course they are correct that the cup they brewed with lower water temperature tasted better to them. A refractometer might be a good tool for analyzing it, but an incredibly low percentage of coffee enthusiasts got one and would take the the time to test it out.

It may just be that when they adjust their pour regime or grind setting, they keep over- or undershooting and never find the sweetspot. When they happen to make a brew that's a bit overextracted they try lowering water temperature and coincidentally hit the sweetspot and give the honors to water temperature.

After spending some time with my own refractometer I quickly saw how big impact on extraction small changes in grind or pour regime can have.

I have no problem with people using water temperature to adjust extraction. As I mentioned earlier, it might even be a good way to do it.


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