From the HBD Archive
From: Pete Soper <soper@maxzilla.encore.com>
Subject: problem water
Date: 1989-05-11 21:21:21 GMT

Let me tell you about my water. It is from a community
well that serves perhaps 25 homes. It has a total hardness
of only 100 parts per million which wouldn't seem to be
too bad. However this water is deceptively alkaline. While
it starts off with a pH of 7.4, it contains buffers that
resist acidification. This means a given amount of acid
naturally present in homebrew ingredients will have less effect
on pH than it would on softer water. Worse, and the part that
I cannot understand is the fact that after boiling this water
(very vigorously with exposure to air and after having been
aerated to start with), the pH goes to 9.2 and the buffering
effect is stronger than before. This is the opposite effect
that I'd grown to expect from reading the popular literature
about water preparation. I repeated this experiment three
times, using an electronic pH meter and careful titrations to
convince myself I was getting this backwards effect.
Based on my experience, alkaline water is terrible for almost
any kind of homebrewing. Only recipes calling for lots of
roasted grains work out properly without resorting to drastic
measures. Roasted grains contribute a lot of extra acidic material
and so can overcome the buffering of the water and get the pH
down to a proper range for the wort boil and fermentation in
this situation.
The range of the wort pH at the start of the boil should be
5.2 to 5.8, depending upon who you read, although most suggest
a range of 5.2 to 5.5 is the ideal. Who cares if this is a bit
high, you might say. Well, there are a whole slew of bad things
waiting to happen when the pH gets too high, but just to name one:
most spoilage bacteria run away and hide when the pH of a medium
falls to 5.8 or below. Above this they can thrive and give you a hard
time. Also, for all grain brewing, the pH of the mash is a critical
factor since, as one example, astringent tasting tannins can
dissolve out of the grain if the pH gets too high. I've also
noticed a correlation between high pH and crummy hot breaks,
but this is also backwards from common wisdom and so is possibly
superstition.
So alkaline water is a special kind of misery and the one
I have to live with. I wish I knew why boiling with aeration
doesn't help or something else I could do to counteract this.
As it is I've started bringing gallon jugs to work where the water
is very soft.
---------------------------------------------------------------
Pete Soper, Encore Computer Corp, 901 Kildaire Farm Rd., bldg D
Cary, North Carolina 27511 USA phone 1 919 481 3730
arpa: soper@encore.com (129.91.1.14)
uucp: {talcott,linus,bu-cs,bellcore,decvax,necntc}!encore!soper

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