Fix:
..mash pH has been known for a long time to be very important (De Clerk, 1957). The classic rule
is for the chilled wort to have a pH of 5.0 - 5.2 and, to achieve this level, it is desirable to establish a mash
pH in the range 5.2 - 5.4 (Hind, 1950). This range, first of all, is favourable to enzymatic activity
..the
enzymes activities do not decrease by much if the pH levels are more acid, but there is typically a sharp
decrease if the pH becomes more basic (alkaline) :
Amylase Activity at 60 C
pH Activity (%)
4.8 = 98
5.0 = 99
5.2 = 100
5.4 = 95
5.8 = 85
6.2 = 65
Another equally important factor is that high pH mashes, say above 5.5, tend to lead to dull malt flavour
that lacks definition (Narziss, 1992). Hop flavours are also negatively affected
in modern practice,
the focus has turned to the pH (rather than the specific gravity) of the wort collected from the sparge
because pH increases with the extraction of undesirable astringents. A general rule is to terminate the
sparge when the pH of the collected wort increases much beyond 0.1 pH units higher than the mash pH. In
any case, it should not exceed 5.5.
Noonan:
..pH is of utmost importance to the brewer. Appropriate acidity is a prerequisite of a
successful brewing cycle. Enzyme activity, kettle break, and yeast performance rely on conducive acidity
in the mash, wort, and beer.
Summary: The ideal pH for all mashes is in the range 5.2 5.4. Too low is better than too high, for
reasons of enzyme efficiency and possible extraction of astringents during end sparging. The mash pH affects the pH throughout the remainder of the brewing cycle, including that of the finished beer.
