Annual Water Report came! Now what?/ Alkalinity vs. bicarbonate

[hifidelity]

I've been brewing for a little over a year now (9 extract batches and 1 all grain, and all grain from now on) and I'm looking to take my beer to the next level. I figure water was the next obvious step.

Just yesterday I was searching for a company that could analyze my water and I was getting ready to send in a sample. As luck would have it I can save my $27 because my Annual Drinking Water Quality Report came from my local water works. It's WAY more thorough than I remember it being in the past. That could be because I care now since I'm a brewer, or because it seems like this is an exceptionally good report (no red flags, which is uncommon since it's a rural area with a cobbled-together infrastructure).

Here are the things BeerSmith 2 asks for and my levels:

PH: 7.20
Calcium: 44.80 ppm
Magnesium: 2.70 ppm
Sodium: 3.35 ppm
Sulfate: 4.05 ppm
Chloride: 4.35 ppm
Bicarbonate: ???

This brings me to alkalinity, which is mentioned on my report, but "bicarbonate" isn't. A quick google search leads me to believe they're the same/similar, but I want to make sure. My "Total Alkalinity" is 128.00 ppm, but it makes no mention of bicarbonates. It also states my "Total Hardness" is 123.00 ppm. What affect does this have on beer?

I'm very new to the chemistry side of brewing, but knowing what my starting point is is very exciting since I know that it will help me be able to adjust my water depending upon the style that I'm brewing. Any help would be appreciated!

 

[EcuPirate07]

Alkalinity = bicarbonate and vis versa per my understanding and the water company can list it either way.

 

[mabrungard]

Alkalinity is primarily a product of the carbonate and bicarbonate content of the water. In conjunction with the water pH, the relative concentrations of those ions can be back-calculated from the alkalinity value. The Bru'n Water program has a calculator for that.

 

[ajdelange]

This brings me to alkalinity, which is mentioned on my report, but "bicarbonate" isn't.

That's because bicarbonate ion content is relatively hard to measure compared to alkalinity which is relatively easy and because no one really cares about having an explicit value for bicarbonate ion concentration. One might at first assume that it is necessary to know bicarbonate ion content in order to predict the effects of added acids and bases and to know the effect of the carbonate system on malts but in fact it is only the relative mole fractions of carbonic, bicarbonate and carbonate that are needed along with C, the total moles of all three. This is relatively easily found from water pH and alkalinity, The details of this calculation and an explanation of the detailed relationship between alkalinity and bicarbonate content are found at https://www.homebrewtalk.com/showthread.php?t=473408.

Where the water is potable it is largely devoid of phosphate and the salts of other weak acids, alkalinity is, at nominal pH, largely determined by bicarbonate content. At higher pH carbonate and hydroxyl ions have influence but most homebrewing calculators ignore these (and phosphate, silicate, bisulfate...) and declare bicarbonate_concentration = 61*alkalinity/50.

My "Total Alkalinity" is 128.00 ppm, but it makes no mention of bicarbonates.

This makes your bicarbonate ion concentration approximately 156 mg/L but what are you going to do with that number? The unfortunate answer is that many spreadsheets and calculators use that number as a proxy for alkalinity, converting it back to an alkalinity value for use in internal calculations.