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St Paul watershed averages

I was adding January 2014 to my list today and realized I have never posted all the years of data I have kept record of in one post/ reply, as much has been only listed anecdotally in response to question/s on the board.

I live right in central St Paul and have consistently used our tap water with or w/o adjustment to brew either extract/ allgrain for 20+ years and have only two super minor issue/ inconvenience (Listed below tables) when brewing in this great watershed but always stellar results for sure. For sake of simplicity I will be listing only averages to give a brief idea of what to expect year to year. I will come back to this thread later and expand more on what to expect seasonally. The sulfate is/ was listed only tri-annually by the utility as (20/21) as I noted below, until St Paul utility explained how to find monthly SO4 readings after 2012.

Ca: 28
Mg: 5
Na: 16
Cl: 34
SO4: 20
HCO3: 62
Alk: 51

Ca: 23
Mg: 7
Na: 17
Cl: 37
SO4: 21
HCO3: 61
ALk: 50

Ca: 25
Mg: 6
Na: 18
Cl: 38
SO4: 21
HCO3: 66
Alk: 54

Ca: 22
Mg: 6
Na: 18
Cl: 35
SO4: 23
HCO3: 66
Alk: 54

Ca: 22
Mg: 7
Na: 20
Cl: 38
SO4: 17
HCO3: 66
Alk: 54

5 yr Average

Ca: 23
Mg: 6
Na: 18
Cl: 36
SO4: 20
HCO3: 64
Alk: 53

January 2014
Ca: 19
Mg: 11
Na: 20
Cl: 33
SO4: 12
HCO3: 71
Alk: 58

Now the only two inconveniences/ issues I have ongoing when using our water is:

a. Accurately predicting/ calculating brew-day alkalinity to a “T” for sparge additions for PH adjustments. What I mean here is I can use a broad average as a good target to gauge mash PH in the models such as brunwater or brewersfriend / Kai presents and hit around +/- 0.10 PH points. BUT in sparge I am always at/ or under 6.00 PH but it varies from 5.0-6.0 depending on actual alkalinity on the day I brew although it is probably 50/50 as one half of batches do hit predicted PH due to lucky guess. I would prefer to hover around 5.50 PH average matching my mash PH as I fly sparge only. This is only semantics for the uber-interested as no matter what my final runnings have never jumped over 5.80 Ph. So definitely use the apps in confidence with the above averages along with monthly reports St Paul does list is the take away for the newer members.

As luck would have it there is solution to (a.)
I/ you can buy a Alk/ hardness/ Kw fish keeping kit and then hit uber-accurate mash/sparge PH numbers because we are testing the Alkalinity the day of brewing. Also YRMV as using the app/s are still a skill based science as the models are only predictions, you must still understand the principles and be able to adjust on the fly if necessary.

b. Our Chlorine/ Chloramine levels are always at/ and listed close to the highest level allowed, which is 4.0 ppm. On average throughout the years I have noticed we hover around 3.5, never dropping under 3.30 ppm.

Again as luck would have it there is solution to (b.)
I/ you can use campden/ Potassium metabisulbite to eliminate this threat. I do use around 0.25 tablet campden per 5 gallons water and have no issue, just thought it needed mention again for any skill-level St Paul brewer unaware of this tool also.

wow - thanks for such a useful post!

Hey JT, Thanks for the reply. It reminded me to come back to the seasonal points I wanted to touch on.

Most common years you will see the following happen.
Very late winter/ early spring (Jan-March) there is typically very little rainfall or snowmelt, so the alkalinity tends to hover around 60 ppm +/- 5ppm and calcium tends to be around 25 ppm. Again a fish keeping alk kit solves this guesstimating. The reason I am spelling this out is because even with a monthly report your current alkalinity might be much lower or higher than reported 0-60 days ago depending on precipitation or lack thereof.

Jan 2010: 57 alk/ Ca: 24
Jan 2011: 61 alk/ Ca: 25
Jan 2012: 55 alk/ Ca: 23
Jan 2013: 64 alk/ Ca: 25
Average: 59 alk/ Ca:24

In spring (Apr-Jun) most common years will see tons of snowmelt and rain. So during this period you can expect the alkalinity to hover around 50 ppm +/- 5ppm and calcium tends to be closer to 20 ppm.

May 2010: 42 alk/ Ca: 19
May 2011: 50 alk/ Ca: 24
May 2012: 45 alk/ Ca: 17
May 2013: 51 alk/ Ca: 19
Average: 47 alk/ Ca: 20

During fall it can go either way, as some years it might be a freak weather year like 2010 when it started melting quickly in early march and rain came and didn’t stop until November. So depending on current quarterly trends you can use the monthly reports and guide your decision based on the precip or lack therof around the brewday. Typically we should rise towards 55 ppm in the middle of summer and go back towards 50 when fall rains come in.

Sept 2010: 49 alk/ Ca: 23
Sept 2011: 51 alk/ Ca: 24
Sept 2012: 60 alk/ Ca: 27
Sept 2013: 48 alk/ Ca: 23
Average: 52 alk/ Ca: 24

Usually by November the hard rains come to a halt and we start to accumulate snow and the alkalinity will rise back up towards 60 ppm.

Nov 2010: 55 alk/ Ca: 23
Nov 2011: 55 alk/ Ca: 25
Nov 2012: 62 alk/ Ca: 20
Nov 2013: 54 alk/ Ca: 19
Average: 57 alk/ Ca: 22

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