Water Chemistry

I am working through Bru’n Water for this years attempt at an Oktoberfest. I have targeted Munich unboiled and need addition CaCO3 at 0.7g/gal to get my Ca2+ and CO3 to target. This unfortunately means that I now need 2lbs of acid malt to get my mash pH down (way more than my normal). There is mention of post-boil targets for Munich as well. According to this target, I need 0.2g/gal of CaCO3 after diluting 50:50 with RO, and then only 1lb acid malt.
Which target should I use?

Not sure why you are getting the numbers that you are getting, but don’t use 1-2 lbs of acid malt. I usually use 2-4 ounces.

I usually go with the more generic profiles like “amber malty” or “Yellow bitter” and stay away from water profiles of “cities.”

Here is my last oktoberfest summary. I use 60% RO water with some pretty hard tap water mixed. No acid malt in this. I used .5 grams gypsum and 2 grams CaCl in 5 gallons of mash water shooting for the amber malty numbers below.

Calcium (ppm) Magnesium (ppm) Sodium (ppm) Sulfate (ppm) Chloride (ppm) Bicarbonate (ppm)
55.0 5.0 15.0 35.0 49.0 105.0

That gave projected pH of 5.3

An O’fest would never be brewed with the unboiled Munich water. It is far too alkaline. You should notice that the boiled profile substantially reduces the alkalinity and makes it more feasible to brew lighter colored beers with the ‘treated’ water.

You don’t add acid and an alkalinity contributor to the same water. Its one or the other, not both. The bicarbonate target is a first guess, you should not blindly pursue that concentration. The number you want to be correct is the predicted mash pH. Don’t worry about bicarbonate or RA.

The good thing is that chalk does not add appreciable alkalinity unless it is predissolved into water under CO2 pressure. Adding dry chalk or a chalk-water solution (without the CO2 treatment) does not work. If the water really needs alkalinity, I strongly recommend using pickling lime.

Take the chalk addition out and see where the pH prediction falls. You may find that the prediction falls in a decent range without acid. However if your source water has alkalinity, then more acid may be needed.

I think the issue is the added bicarbonate to get to Munich’s target 295ppm (unboiled) or 95ppm (boiled). Using the amber malty profile brings back the acid malt to 0.5lb and 0.5g/gal CaCl, much more reasonable. Thanks for the input.

For sure. Even after boiling that water, the brewers of that era and location would have had to perform an acid rest or acid malt addition to knock the rest of the alkalinity out. The Amber profile takes most of that out and gives you a better starting point as a target. I hope that beer tastes great.

Martin, you’re my hero. :cheers: