# Brew Water Temperature



## The Systemic Kid (Nov 23, 2012)

Useful video from James


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## ratty (Sep 22, 2019)

Very interesting.

I've been 'accidentally' putting 100c water directly into the French press from the Osmio.

My thoughts were because of the long drop on the Osmio to the bottom of the French press, the water would cool somewhat.

Seems according to James I don't need to worry at all!


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## the_partisan (Feb 29, 2016)

I really didn't understand the point of this video. Am I missing something? you should use as hot water as possible.. until you shouldn't?


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## Mr Binks (Mar 21, 2019)

the_partisan said:


> I really didn't understand the point of this video. Am I missing something? you should use as hot water as possible.. until you shouldn't?


 I think the point being made is that buying a super posh kettle that will give an exact temperature of water or indeed getting all bent out of shape about exact temperatures is a complete waste of time as by the time you have poured the water the temperature will have changed enough that it makes no difference.


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## Drewster (Dec 1, 2013)

Just paraphrasing:

"the hotter the brew water the more energy it provides for chemical reaction..."
"... and one of those chemical reaction 'groups' is stuff going into solution..."

Now it is a long time since I did chemistry....
but "brewing coffee" isn't a chemical reaction is it?
Or more generically dissolving things isn't a chemical reaction is it?
and
Isn't brewing coffee "just" dissolving the "coffee stuff" in water? (There is an awful lot of chemical reaction involved in the roasting/cooking of coffee but that ain't what we are talking about)

NB - I am not for a moment questioning wether temperature has a bearing on how much of "stuff" gets dissolved and even "what stuff" gets dissolved - but that isn't a "chemical reaction"...

As you already know I am not a fan of "Celeb Coffee" and all the smoke mirrors and bullshit spouted.
People who measure EY and TDS etc are at least using "real" terms and methodology - which could come under the banner of "science". 
So even if I don't "do it" per se - the exponents of it are at least being "scientific"...

But isn't "James" just trying a little too hard to sound "scientific" in this?

You might also argue that using scientific terms incorrectly (pseudo-science?) immediately followed by such words as "stuff going into solution" is damning in itself... although obviously I am guilty of throwing "stuff" in all the time... even within this post.... ;-)


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## John Yossarian (Feb 2, 2016)

Brewing is extraction if we were looking for scientific aspect and extraction is ensuring the dissolution of otherwise not very water soluble "stuff". 
I am with Drewster on this.


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## DavecUK (Aug 6, 2013)

ratty said:


> Very interesting.
> 
> I've been 'accidentally' putting 100c water directly into the French press from the Osmio.
> 
> ...


 I suspect by the time the water hit the coffee bed it was around 91-93C. I watched the video, I remembered all the guff that has been spouted over the last almost 20 years. I remember being ridiculed (I'm not going to say by who) when I said adding boiling water to an espresso shot to make an Americano doesn't "burn the coffee". The common sense brigade now prevails where they realise adding water of whatever temperature to an already extracted espresso doesn't change anything. Loads of little Hobby horses come up over the years, often with little verification that are taken as gospel. e.g. never extract espresso onto ice, I always have, no problem for me.

The one common thing about it all....these ideas are pushed by people in the business, people who make a living from coffee. Special brewing scales, special kettles, special papers, special tampers, special distributors, temperature measuring milk jugs, special shower screens, filter baskets, special bloody everything. Add coffee to the name of a thing and you can double the price.

With brewed coffee, it doesn't seem as critical as people suggest. Mark gave me an OXO good grips brewer, I can fill the top chamber, it pours at a set rate through small holes into the cone/filter paper and makes a nice brew...it's £15 from Amazon. Seems to work OK. I did get a proper brewing cone and I think some unbleached papers and a special bloody scale, then I will try temperature controlled water/trick timings etc.. and see if it makes a difference. Mark offered me a kettle, but realistically I can get water at whatever temp I want from the group of any of my espresso machines. When I get time to do the test I will be sure to report back. In the meantime if any of you can afford 15 quid try the OXO brewer, see what you think, it will help the price of my Oxo and Amazon shares. In fact I like it that much I was going to do a mini review on it.










https://www.amazon.co.uk/OXO-Grips-Coffee-Maker-Water/dp/B01ENK41Q6/ref=sr_1_4?crid=13X9EW3YS9ABK&keywords=oxo+good+grips+cold+brew+coffee+maker&qid=1583681752&sprefix=Oxo+good+grips+brew%2Caps%2C151&sr=8-4

Skip to 4m into the video for a shot of the brewer in action.






The only thing I do know for a fact is the temperature of extraction of espresso from an espresso machine is rather important and does have a discernable effect....1C is the sort of resolution required.


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## pj.walczak (Sep 6, 2017)

Drewster said:


> Or more generically dissolving things isn't a chemical reaction is it?


 Interesting.

I did some googling and found this article. I do not have enough scientific knowledge to decide how accurate is this article, but because it is n the SCA site, at least it is worth reading.

And from experience, there is a difference in coffee taste related to temperature. It is also very noticeable with good teas. Try brew coffee with 80 C and boiling water, the difference is obvious. The winner - as long as you have good coffee the one with boiled water is much better. If you want opposite results, do the brewing of good green tea, 70-80 C versus boiling water. Here, the clean winner will the tea brewed in cooler water.

Few quotes:

"When chemists speak of extraction they are referring to the specific separation of a particular substance from a mixture (or whole product)."

"Hydrolysis is one of these types of reactions. It is a general chemical reaction that occurs when water reacts with another compound to alter it or break it down."

"The second type of chemical reaction that occurs during coffee extraction are known as dissolution processes. In dissolution, water solubility of compounds allows them to be dissolved into the water and hence extracted into the coffee beverage. Examples include chlorogenic, acetic, malic, and other acids, as well as caffeine and trigonelline (Arya and Rao 2007). "

"Finally, the third type of chemical reaction which occurs during brewing is known as diffusion. In diffusion, wherever solutes are not distributed uniformly throughout a solution, there is a concentration gradient. Consequently, solutes diffuse from zones of high concentration to where it is lower. In coffee, this means areas of high coffee concentrations (the grounds) move to areas of low coffee concentration (the water). An important particular case where these concentration gradients result in the diffusion of compounds is called osmosis. Osmosis is the net movement of solvent molecules through a membrane (in this case, a cell wall) into a region of lower solute concentration. "


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## MWJB (Feb 28, 2012)

Doesn't really matter what you call it.

Pour hot water on coffee, brown liquid comes out.

Too coarse, too cool, you limit the amount of brown stuff.

It's almost impossible to brew too hot in a static immersion, or a manual pourover.


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## the_partisan (Feb 29, 2016)

Seems for World Aeropress Championships, most people preferred 80-85C (looking at the winners), which is kind of interesting. Lower temperatures do extract a different profile and prevent extraction of the bitter tasting compounds. It's not really maximising extraction (which IMHO is pointless anyway) or sweetness, but can produce a tasty brew.

With drip you do need much hotter water (92C+), though esp for quicker brews or it just tastes quite flat. For pour over 100C seems to work just fine, I never had any issues.


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## MWJB (Feb 28, 2012)

the_partisan said:


> Lower temperatures do extract a different profile and prevent extraction of the bitter tasting compounds. It's not really maximising extraction (which IMHO is pointless anyway) or sweetness, but can produce a tasty brew.


 Is it a different profile, or a profile that you'd get with a similar low extraction in espresso/drip (sorry if this sounds like splitting hairs)? I've had very tasty espresso at 12-14%EY, no sourness, no bitterness, sweet, smooth, but simple. I've had similar in big dosed Clever brews too.

The downside is the amount of coffee you have to use for a typical cup at reasonable strength.

I have yet to see much evidence that temperature makes much difference to what is extracted, compared to how much.


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## the_partisan (Feb 29, 2016)

I've also tasted some lower EY immersion brews using the 30g aeropress recipe and it tasted quite good, with a big hit of flavour but then not much aftertaste. I haven't got that low EY with drip, I think the only time I hit so low EY in drip was due to not all coffee bed getting enough water, which tasted pretty horrible. I think it does exert some selective pressure, similar to grinding coarser. It's quite likely different compounds extract at different rates. I can't really say if lower temperature has exactly same effect as a coarser grind or not though. Someone should have likely studied this ?


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## Kevin Tran (Dec 20, 2019)

I think if we pour with hot water~ 100 C degree, the coffee will be sour.


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## Jony (Sep 8, 2017)

Best Products House said:


> Might be, might be not, have to see by doing practically. Don't you think so?


 DO not spam us with links, welcome


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## MWJB (Feb 28, 2012)

Kevin Tran said:


> I think if we pour with hot water~ 100 C degree, the coffee will be sour.


 No, your coffee will be normally brewed. Boiling water has been recommended for coffee brewing for at least 70 years.

At some point the SCAA confused 'brew temperature' for 'brew water temperature' and all the noobies who fell to earth in the last rain shower were then under the impression that their water had to be 92/94c in the kettle, but in fact this is the offset (described by MIT scientists in the 1950s) in the brewer when you pour boiling water from the kettle (can even be a little greater, like 90c, if you pour slowly, or use heavy ceramic cupping bowls etc.).

Your brew tamp also declines during the brew in manual brewing, so you're looking t a 3-4c change in temp in the course of a pourover, 20c or more in French press/cupping. Nobody brews at a single temperature.


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