Script to calculate water salt additions - Home Brew Forums

 Home Brew Forums > Script to calculate water salt additions

01-12-2011, 10:36 PM   #1
doobliebop
Recipes

Mar 2009
Denver, CO
Posts: 244
Liked 5 Times on 2 Posts

I wrote this script to calculate the optimal amount of brewing salts to add to your water profile to end up with a target profile. I grabbed most of my numbers from ProMash, and so far this seems to be working well for me.

It is a python script, so you'll need the python interpreter with numpy, and the PyIMSL numerical libraries (freely available here: http://www.imslaps.com/products/imsl/pyimsl/)

Code:
```from numpy import *
from imsl.math.linLsqLinConstraints import linLsqLinConstraints
from imsl.math.writeMatrix import writeMatrix
from imsl.math.vectorNorm import vectorNorm

#Replace the values in base_water with your water profile
base_water = [26.0, 3.6, 13.2, 28.0, 12.2, 68]
#################Values taken from ProMash################
burton_on_trent = [268., 62., 30., 638., 36., 141.]
calistoga_mineral = [11.1, 62., 30., 638., 36., 141.]
distilled_water = [0.,0.,0.,0.,0.,0.]
dortmund = [260.,23.,69.,240.,206.,270.]
dublin = [118., 4., 12., 54., 19., 319.]
edinburgh = [140., 36., 92., 231., 60., 270.]
london = [90., 4., 24., 58., 18., 123.]
marin_county_ca = [12., 10., 15., 17., 13., 74.]
munich = [76., 18., 1., 10., 2., 152.]
pilsen = [7., 3., 3.2, 5.8, 5., 9.]
vienna = [200., 60., 8., 125., 12., 120.]
yorkshire = [105., 17., 23., 66., 30., 153.]
###########################################################
target = burton_on_trent

#Salt contents (PPM / (grams per gallon))
caso4 =  [61.5, 0.0, 0.0, 147.4, 0.0, 0.0]
mgso4 =  [0.0, 26.1, 0.0, 103.0, 0.0, 0.0]
nacl =   [0.0, 0.0, 103.9, 0.0, 160.3, 0.0]
nahco3 = [0.0, 0.0, 72.0, 0.0, 0.0, 189.0]
cacl2 =  [72.0, 0.0, 0.0, 0.0, 127.4, 0.0]
caco3 =  [105.8, 0.0, 0.0, 0.0, 0.0, 158.4]

# The overall goal here is to find x ST:
# Ax =~ b
# x >= 0

a = transpose([caso4, mgso4, nacl, nahco3, cacl2, caco3])
b = array(target) - array(base_water)
xlb = [0.] * 6
xub = [-1.0e30] * 6
c = []
con_type = []
bu = []
bl = []
residual = []
x = linLsqLinConstraints(a, b, c, bl, bu, con_type,  xlb, xub, residual=residual)

ion_labels = ['', 'Ca', 'Mg', 'Na', 'SO4', 'Cl', 'HCO3']
salt_labels = ['', 'CaSO4', 'MgSO4', 'NaCl', 'NaHCO3', 'CaCl2', 'CaCO3']
writeMatrix("Salt amounts to add \n(Grams per Gallon)", x, colLabels=salt_labels)
writeMatrix("Target Profile \n(PPM)", target, colLabels=ion_labels)
writeMatrix("Base Water + Recomended Salt Additions \n(PPM)", dot(a,x) + array(base_water), colLabels=ion_labels)
writeMatrix("Residuals \n(PPM)", residual, colLabels=ion_labels)
print ("\nNorm of residual = %f" % (vectorNorm(residual)))```
Here's a run calculating additions from my water to Burton on Trent. Plugging these numbers back into ProMash I get these exact totals.
Code:
```ryan@ubuntu-desktop:~/Desktop\$ python water.py

Salt amounts to add
(Grams per Gallon)
CaSO4        MgSO4         NaCl       NaHCO3        CaCl2        CaCO3
2.888        1.817        0.106        0.000        0.083        0.489

Target Profile
(PPM)
Ca           Mg           Na          SO4           Cl         HCO3
268           62           30          638           36          141

Base Water + Recomended Salt Additions
(PPM)
Ca           Mg           Na          SO4           Cl         HCO3
261.3         51.0         24.2        640.8         39.8        145.5

Residuals
(PPM)
Ca           Mg           Na          SO4           Cl         HCO3
-6.67       -10.98        -5.81         2.78         3.77         4.45

Norm of residual = 15.513117```
Hope somebody finds this useful!
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09-07-2012, 05:29 AM   #2
htc
Recipes

Oct 2010
Potosi, Missouri
Posts: 137
Liked 13 Times on 9 Posts

This is the first calculator I've found that (supposedly) calculates the proper additions to reach a desired water profile, rather than calculating the profile based on my additions. The first problem is that the link above for the python interpreter doesn't work. The second problem is that I have no idea what "python" or "numpy" are. Help please.

09-11-2012, 07:11 PM   #3
HopSong
Senior Member

Recipes

Sep 2011
Santa Rosa, CA
Posts: 1,945
Liked 101 Times on 89 Posts

Got an 500 Error.. Internal Server on the link
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Cheers, Bill
Hop Song Brewing

09-16-2012, 03:50 AM   #4
hafmpty
Recipes

Jan 2010
Cincinnat, OH
Posts: 545
Liked 59 Times on 40 Posts

I'd love to be able to use this. Unfortunately, like a previous poster, I don't know how exactly. I've used a python script a couple times for something I was doing about a year ago, but I had no idea what I was doing. Could you (would you?) put together a "How-To" of getting the proper software/program and actually running the script? That would make this uber-helpful. Thanks so much.

09-19-2012, 09:33 PM   #5
htc
Recipes

Oct 2010
Potosi, Missouri
Posts: 137
Liked 13 Times on 9 Posts

^^^^=awesome!