After finding a report from the Roman water utility, I made use of the Water Profile tool in Beersmith to get a feel for what I was working with. As you can see below the water is extremely alkaline (the red dot gives it away). Thinking I may be able to work around this alkalinity in a similar manner as I had in the past, I decided to use food grade lactic acid to counteract the alkalinity in the water. I found that a large quantity of acid was necessary to obtain a mash pH in my desired range. The beers that resulted from this water modification had a distinct, artificial "twang" to them. After doing some online research, I determined that the culprit of this strange flavor was the acid.
|398 ppm HCO3-!|
In order to find an alternate method to counteract alkalinity, I investigated the online forums provided by the American Homebrewers Association (AHA) and dug a little deeper into 'Water' by Palmer and Kaminski. I determined that I had two options for reducing the alkalinity in my brewing water: pre-boiling or pre-treating with lime. Both methods result in the reduction of bicarbonate (HCO3-) through the precipitation of chalk (calcium carbonate / CaCO3).
|Pickling lime to the rescue.|
Based on energy intensity and the likelihood for mineral deposits in my boil kettle, I decided that pre-boiling was not the route I wanted to go. Instead, I got my hands on some pickling lime (calcium hydroxide / Ca(OH)2) and followed Braukaiser's well written guide on reducing alkalinity. My process looks very similar to the one outlined in the guide. I first filter warm tap water through an activated carbon filter to remove chlorine and transfer it to a large bucket that I use as a treatment vessel. I add equal parts calcium chloride and calcium sulfate to my carbon filtered tap water to increase the calcium content and maximize the precipitation of chalk. Following this addition I add lime, stir well, and allow anywhere between 12 and 24 hours for the precipitated chalk to settle. Once settling is complete I decant the treated water off of the settled chalk using my auto siphon. Utilizing this very simple process I have found that the amount of acid necessary to achieve an appropriate mash pH is significantly reduced and the strange "twang" character I had in beers modified solely with acid has been eliminated.
|Settled chalk after water treatment.|