First time poster so pls be gentle…
Another SE Qld brewer here (Beechmont). We’re on tank water and until we fitted a calcite filter, our water was at pH 4.2-4.5 - sufficiently acidic that it was stripping copper out of the shower breech and leaving blue/green stains on the shower tiles. We have a large tank with relatively little turnover (only 2 of us) so the water has plenty of opportunity to absorb more CO2 and reduce pH beyond normal rainwater pH. The calcite filter leaves the pH at around 8.5
All that said, I’ve just moved over to brewing with Coles/Woollies spring water as I‘ve been having terrible problems with a very strong bitter, back-of the-throat aftertaste since I started. I’m an extract brewer and have found the same problem with different styles - stout, red ales, Helles, wheat and euro lager. It’s the same story with all of them - swallow the beer, count to 3 and there it is - a horrible, lingering bitter, harsh aftertaste in the upper throat. I’ve tried a number of experiments with split batches - boiling the tank water, drawing it off before the calcite filter, different fermenters, etc without success, apart from an experiment with spring water which was OK. To endorse this, I’ve just finished a Bavarian Hefeweizen clone from AHB made with spring water and it tastes wonderful.
At least I have a way to make good beer now, but I’d love to know what the problem is with our tank water. The tank is really clean (I can see the bottom of the tank through the inspection hatch), water tastes great and we have a floating draw off pipe so we always get the freshest water. A local lab tested a sample and it passed with flying colours (no ion values reported unfortunately). The only thing I can think of is that a couple of years ago (before we had the calcite filter) I tried correcting the pH with sodium bicarbonate (I’m a retired chemist so reasonably confident the quantity was correct) so there may be residual Na+ there (I’m assuming all the bicarbonate will have dissipated by now). That said, we‘ve had so much rain since then, it must be diluted by now.
Sorry for the windy post and hope I haven’t hijacked the thread. Any enlightenment gratefull received