Monday, February 12, 2018

Treatment of Highly Alkaline Water

Hello beer brewing friends! I apologize for the long hiatus. In addition to getting accustomed to my new lifestyle in Italy, I've been working out a few kinks on my new brewing system. As mentioned in a previous post, since moving to Italy I've made several changes to my process. The most difficult of the changes I've encountered thus far has been working with the tap water.

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.

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