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Date: 10 Jun 2006 01:11:51
From: CoffeeGreek
Subject: Brita filtered water: pH problem
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I have been using a Brita filter for a while to prevent scaling of my
boiler. No problems there - no scale at all. However, I have been
geting consistenly better tasting coffee, brewed or espresso, with tap
water. Having gone through Jim's Insanely Long FAQ, I decided to check
the Brita water with a conductivity meter and a pH meter and the
results were quite surprising. I used calibrated instruments, not
strips. Conductivity is in microSiemens (uS). To get CaCO3 ppm you
divide by 2, to get TDS you multiply by 0.66.
Tap water: 300 uS, pH 7.6
Boiled tap water: 210 uS, pH 8.4
Brtia water: 180 uS, pH 6 when fresh, 6.5 after standing in the jug
overnight
Boiled Brita water: 180 uS, pH 9.6 !!
This is over 10 times more alkaline than boiled tap water. The reason
for this huge increase in pH, from 6 to 9.5, is that the Brita
ion-exchange resin removes calcium and magnesium ions and replaces them
with H+ hydrogen ions, resulting in the low, acidic pH of the filtered
water. It does not remove carbonates, which are now present in excess
as HCO3-. When boiled, CO2 gas escapes leaving OH- hydroxyl ions behind
and thereby increasing the pH. Boiling tap water on the other hand
results in CaCO3 precipitation as scale, so carbonate ions are also
removed and the increase in pH due to CO2 release is less.
I wonder if anyone knows the effect of pH on coffee extraction and in
particular what the effect of alkaline water is.
George
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Date: 10 Jun 2006 09:34:12
From: CoffeeGreek
Subject: Re: Brita filtered water: pH problem
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Omniryx@gmail.com wrote:
> But...if you ARE going to go scientific, be sure that your taste
> comparisons are proper double blind studies. Simply cupping one water
> and then the other won't get it if you intend to be all scientific and
> that.
Phew, if my sticking a pH probe in a glass of water got you so cross, I
can only imagine your reaction had I used my mass spectrometer! If you
stick with this group long enough you will see that many get so
scientific as to use THERMOMETERS to measure water temperature! ;)
My humble apologies for not meeting your exacting scientific standards
with a proper double blind study. I only dared to ask a question: does
anyone know what effect water pH has on coffee extraction. If you can
contribute something more informative than "use tap water if you like
it" (which I did anyway), feel free to do so.
George (who got up the wrong side of his bed today)
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Date: 10 Jun 2006 11:56:57
From: Johnny
Subject: Re: Brita filtered water: pH problem
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"CoffeeGreek" <coffeegreek@in.gr > wrote in message
news:1149957252.414901.202550@c74g2000cwc.googlegroups.com...
>
> Omniryx@gmail.com wrote:
>
> > But...if you ARE going to go scientific, be sure that your taste
> > comparisons are proper double blind studies. Simply cupping one water
> > and then the other won't get it if you intend to be all scientific and
> > that.
>
> Phew, if my sticking a pH probe in a glass of water got you so cross, I
> can only imagine your reaction had I used my mass spectrometer! If you
> stick with this group long enough you will see that many get so
> scientific as to use THERMOMETERS to measure water temperature! ;)
>
> My humble apologies for not meeting your exacting scientific standards
> with a proper double blind study. I only dared to ask a question: does
> anyone know what effect water pH has on coffee extraction. If you can
> contribute something more informative than "use tap water if you like
> it" (which I did anyway), feel free to do so.
>
> George (who got up the wrong side of his bed today)
>
Pay no attention, George. The internet is full of people who feel a need
to be ugly to others.
ROTFLMAO....
Sorry Will, just couldn't resist. :-)
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Date: 10 Jun 2006 07:08:34
From: Omniryx@gmail.com
Subject: Re: Brita filtered water: pH problem
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I'm with someone else from the thread about sifting the coffee through
graded screens: Why not put away the pH meter and just rely on your
buds. If tap water tastes better to you, use it. Occasional descaling
isn't that much of a hassle.
But...if you ARE going to go scientific, be sure that your taste
comparisons are proper double blind studies. Simply cupping one water
and then the other won't get it if you intend to be all scientific and
that.
Will (who does this sort of thing for part of his living)
CoffeeGreek wrote:
> I have been using a Brita filter for a while to prevent scaling of my
> boiler. No problems there - no scale at all. However, I have been
> geting consistenly better tasting coffee, brewed or espresso, with tap
> water. Having gone through Jim's Insanely Long FAQ, I decided to check
> the Brita water with a conductivity meter and a pH meter and the
> results were quite surprising. I used calibrated instruments, not
> strips. Conductivity is in microSiemens (uS). To get CaCO3 ppm you
> divide by 2, to get TDS you multiply by 0.66.
>
> Tap water: 300 uS, pH 7.6
> Boiled tap water: 210 uS, pH 8.4
> Brtia water: 180 uS, pH 6 when fresh, 6.5 after standing in the jug
> overnight
> Boiled Brita water: 180 uS, pH 9.6 !!
>
> This is over 10 times more alkaline than boiled tap water. The reason
> for this huge increase in pH, from 6 to 9.5, is that the Brita
> ion-exchange resin removes calcium and magnesium ions and replaces them
> with H+ hydrogen ions, resulting in the low, acidic pH of the filtered
> water. It does not remove carbonates, which are now present in excess
> as HCO3-. When boiled, CO2 gas escapes leaving OH- hydroxyl ions behind
> and thereby increasing the pH. Boiling tap water on the other hand
> results in CaCO3 precipitation as scale, so carbonate ions are also
> removed and the increase in pH due to CO2 release is less.
> I wonder if anyone knows the effect of pH on coffee extraction and in
> particular what the effect of alkaline water is.
> George
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Date: 10 Jun 2006 15:43:13
From: jim schulman
Subject: Re: Brita filtered water: pH problem
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On 10 Jun 2006 01:11:51 -0700, "CoffeeGreek" <coffeegreek@in.gr >
wrote:
>
>Tap water: 300 uS, pH 7.6
>Boiled tap water: 210 uS, pH 8.4
>Brtia water: 180 uS, pH 6 when fresh, 6.5 after standing in the jug
>overnight
>Boiled Brita water: 180 uS, pH 9.6 !!
>
I'm curious about the high pH of the boiled waters. My expectation
would have been lowered pH as the carbonates are precipitated out. My
first thought is a misreading; perhaps you're measuring hot, and the
temperature compensation is off.
My other thought is that you're deriving TDS, hardness and pH from
just one conductivity reading. This does not seem possible when the
chemical composition of the water changes, since the translation of
one reading into three variables presupposes a fixed mineral
composition and a pH that is at equilibrium (i.e. fully determined by
the carbonates).
For instance, ion softening water does not change the conductivity
reading, and TDS meters will not register a change. However, the
replacement of one Ca or Mg ion by two Na ones increases the true TDS
and decrease true hardness, so that CaCO3 equivalent conversions of
conductivity to TDS and hardness values will be very wrong for ion
softened water (and any water to the extent it has minerals other than
CaCO3).
On the other hand, maybe I don't understand your argument here.
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Date: 10 Jun 2006 12:12:05
From: Omniryx@gmail.com
Subject: Re: Brita filtered water: pH problem
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Johnny wrote:
> Pay no attention, George. The internet is full of people who feel a need
> to be ugly to others.
> ROTFLMAO....
> Sorry Will, just couldn't resist. :-)
WooHoo! Maybe I deserved it, Johnny. I certainly sent poor George the
wrong message.
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Date: 10 Jun 2006 12:10:56
From: Omniryx@gmail.com
Subject: Re: Brita filtered water: pH problem
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Whoa, whoa, whoa, whoa, whoa, George.
I'm not cross. Not at all. Not even a little bit. Not a smidgeon.
Not a scintilla.
Sorry if I sent the wrong message. Not my intention.
Part of what I do in my life as a university prof is to teach research
methods. Therefore, I have no objection whatever to people taking a
scientific approach to what they do. If you intend to introduce a
quantitative approach to your question about water quality then it
would be appropriate to remove other sources of bias, as well. One way
to do that would be to taste the coffee brewed under different
conditions without knowing which set of conditions was which. That's
all. Nothing nefarious. Nothing critical. Nothing cross.
At an entirely personal level, I'd rather just taste as I go along and
decide on that basis. Perhaps this is, in part, about separating my
personal life from my professional life.
Let us know what you learn.
Will
Johnny wrote:
> "CoffeeGreek" <coffeegreek@in.gr> wrote in message
> news:1149957252.414901.202550@c74g2000cwc.googlegroups.com...
> >
> > Omniryx@gmail.com wrote:
> >
> > > But...if you ARE going to go scientific, be sure that your taste
> > > comparisons are proper double blind studies. Simply cupping one water
> > > and then the other won't get it if you intend to be all scientific and
> > > that.
> >
> > Phew, if my sticking a pH probe in a glass of water got you so cross, I
> > can only imagine your reaction had I used my mass spectrometer! If you
> > stick with this group long enough you will see that many get so
> > scientific as to use THERMOMETERS to measure water temperature! ;)
> >
> > My humble apologies for not meeting your exacting scientific standards
> > with a proper double blind study. I only dared to ask a question: does
> > anyone know what effect water pH has on coffee extraction. If you can
> > contribute something more informative than "use tap water if you like
> > it" (which I did anyway), feel free to do so.
> >
> > George (who got up the wrong side of his bed today)
> >
> Pay no attention, George. The internet is full of people who feel a need
> to be ugly to others.
> ROTFLMAO....
> Sorry Will, just couldn't resist. :-)
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Date: 11 Jun 2006 03:09:32
From: D. Ross
Subject: Re: Brita filtered water: pH problem
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Date: 11 Jun 2006 00:15:06
From: CoffeeGreek
Subject: Re: Brita filtered water: pH problem
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jim schulman wrote:
>My first thought is a misreading; perhaps you're measuring hot, and the
> temperature compensation is off.
No, all measurements were at room temperature, several hours after
boiling. I also got the same readings with Brita water straight out of
my espresso machine boiler or freshly boiled in a kettle - both without
any scale present.
> My other thought is that you're deriving TDS, hardness and pH from
> just one conductivity reading.
Used two separate instruments, a calomel probe pH meter and a
conductivity meter. The conductivity to TDS or hardness conversions
were based on a table inside the meter's manual - not sure if they mean
anything or if they are accurate. FWIW, the point I was trying to make
was that Brtia filtering gets rid of about half the hardness in water
(we knew that), creates an acidic water (we knew that), which then gets
very alkaline when boiled (that was new for me). The buffering capacity
of salts dissolved in water is a far too complicated issue to draw any
other conclusions from my measurements.
In any case, let us know if you find any info in your coffee science
books about pH effects on coffee extraction.
Cheers
George
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Date: 11 Jun 2006 11:25:22
From: jim schulman
Subject: Re: Brita filtered water: pH problem
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On 11 Jun 2006 00:15:06 -0700, "CoffeeGreek" <coffeegreek@in.gr >
wrote:
>In any case, let us know if you find any info in your coffee science
>books about pH effects on coffee extraction.
That you should immediately discard water that caustic, since it's
unnatural ;-) Seriously, that's why the result is puzzling. Alkalinity
in natural water is supposedly the result of carbonates only; and
these get precipitated by boiling, which should threfore lead to
increased acidity. I'm not sure what metal leaching in boilers does to
pH or pH measurement, but that woiuld not effect boiling in an SS pot.
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Date: 10 Jun 2006 23:51:00
From: CoffeeGreek
Subject: Re: Brita filtered water: pH problem
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Omniryx@gmail.com wrote:
> Whoa, whoa, whoa, whoa, whoa, George.
>
> I'm not cross. Not at all. Not even a little bit. Not a smidgeon.
> Not a scintilla.
Hey Will, no offence, I wrote my response with a "tongue-in-cheek"
attitute, perhaps that didn't come across. One thing I know well about
usenet posts is how easy it is to misunderstand the true intentions of
the poster based on a few sentences, probably written in a hurry, so I
never take things personally or even seriously.
And I do take your point about taste comparisons. My post was merely
trying to bring attention to the fact that Brita water, which most
people consider acidic, is in fact very alkaline after being boiled.
Hardly a subject worth fighting about!
George
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Date: 11 Jun 2006 12:21:46
From: CoffeeGreek
Subject: Re: Brita filtered water: pH problem
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jim schulman wrote:
Alkalinity
> in natural water is supposedly the result of carbonates only; and
> these get precipitated by boiling, which should threfore lead to
> increased acidity.
But there's a lot of dissolved CO2 in water. When fizzy water goes
flat, it's pH goes up and that's why it tastes flat. CO2 is removed
very efficiently by boiling, therefore the water pH goes up, especially
in the case of the Brita where no more CaCO3 forms as scale to
counteract this increase.
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Date: 11 Jun 2006 19:37:21
From: jim schulman
Subject: Re: Brita filtered water: pH problem
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On 11 Jun 2006 12:21:46 -0700, "CoffeeGreek" <coffeegreek@in.gr >
wrote:
> Alkalinity
>> in natural water is supposedly the result of carbonates only; and
>> these get precipitated by boiling, which should threfore lead to
>> increased acidity.
>
>But there's a lot of dissolved CO2 in water. When fizzy water goes
>flat, it's pH goes up and that's why it tastes flat. CO2 is removed
>very efficiently by boiling, therefore the water pH goes up, especially
>in the case of the Brita where no more CaCO3 forms as scale to
>counteract this increase.
Once the water is boileed, there cannot be enough HCO3- ions left to
go over 7 pH, even with all dissolved gasses out. This is the problem
with your reading -- if it is correct, it cannot be from carbonates.
Even in icecold water, it's hard to get enough carbonates into water
to get above 8pH
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Date: 12 Jun 2006 00:13:12
From: CoffeeGreek
Subject: Re: Brita filtered water: pH problem
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jim schulman wrote:
> Once the water is boileed, there cannot be enough HCO3- ions left to
> go over 7 pH, even with all dissolved gasses out. This is the problem
> with your reading -- if it is correct, it cannot be from carbonates.
> Even in icecold water, it's hard to get enough carbonates into water
> to get above 8pH
Thanks Jim. I guess a few more measurements are in order, hopefully by
someone with a different setting than mine. I still think that the
imbalance in the carbonate buffering system caused by the ion-exchange
process can lead to enough hydroxyl ion production after CO2 escape to
account for the increased pH, regardless of how many carbonates are
left behind. If the boiled water is left standing in air for a while it
will reabsorb CO2 and get back to more acidic values. Checking some
google results (plenty of aquarium owners or beer brewers seem to get
very scientific about their water) I came across this measurement:
>Tap Water: pH 7.8 8 dGH 5 dKH
>Brita Water: pH 6.6 6 dGH 3 dKH
>Boiled Water: pH 9.0 8 dGH 4 dKH
but it was dismissed by the authors because the water had not cooled
down enough. However, pH measurement at a high temperature has the
opposite effect, it gives a lower pH reading: A neutral water (pH 7 at
20C) will measure around 6 at boiling temp and around 7.4 at 4C.
George (who has a degree in chemistry, but that was so long ago....)
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Date: 12 Jun 2006 16:20:18
From: jim schulman
Subject: Re: Brita filtered water: pH problem
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On 12 Jun 2006 00:13:12 -0700, "CoffeeGreek" <coffeegreek@in.gr >
wrote:
>google results (plenty of aquarium owners or beer brewers seem to get
>very scientific about their water) I came across this measurement:
>>Tap Water: pH 7.8 8 dGH 5 dKH
>>Brita Water: pH 6.6 6 dGH 3 dKH
>>Boiled Water: pH 9.0 8 dGH 4 dKH
>but it was dismissed by the authors because the water had not cooled
>down enough.
Cool, everyone gets the effect. You may have been right first time,
the boiling drives out CO2
I doubted this becasue of the relation I reproduced in the FAQ between
alkalinity and pH. This is an equiliibrium relation, after the gas
relaease and absorbtion has stabilized. I thought that reaching
equilibrium only takes a few hours.
If my faith in textbooks is warranted, your boiled water should have
returned to around 7 pH **eventually**. Now I'm wondering whether the
"eventually" is an economist's "in the long run, we're all dead"
equilibrium.
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