Finding the Alkalinity of Your Water Using A Salifert Test
In my previous post about adjusting your water I mentioned something called a “Salifert Test”. It may sound technical and something you don’t want to get yourself involved with but what it does is tell us the alkalinity of your water supply. This alkalinity can then be fed into the water treatment calculator which will then spit out the brewing salts you need to add to your brew and their amounts.
Sometimes this alkalinity will be written on a water quality report which is great we can use that figure however it isn’t always and it definitely wasn’t written on the water report for my area. This is where the Salifert test comes in, it takes only a minute to do and will allow you to test the water on your brew day so any fluctuations in your alkalinity of your water supply will be taken into account. Plus it make you feel like a scientist which is always good.
The Salifert Test you need to buy is to test the alkalinity or Carbonate Hardness. I purchased this one from my local garden centre.
Performing A Salifert Test
The picture below details what comes with the kit, basically it consists of two syringes, one large and one small, a trial jar, a nozzle for the syringe, a blue dye and an agent that reacts with the dye to tell us the alkalinity.
First of all we need to take a sample of the water supply so take the large syringe and fill it with 4ml of water, this is then added to the trial jar. We then take the small bottle marked KH Ind and add 4 drops to the water in the test jar.
The water in the test jar will now of taken on a bluey, green hue. We then put the fine nozzle on the smaller syringe and draw a sample of the KH reagent. The sample will fill pretty much the whole syringe with a small gap of air near the black part of the piston. Draw the agen into the syringe until the lower part of the black piston is exactly on 1.00ml, don’t worry about the air bubble in syringe.
The KH reagent is then added to the water solution drop by drop. After adding each drop give the test jar a little shake to mix up the solution. Continue to add the reagent drop by drop to the solution, you will see that it will take on a shade of pink when swirled then revert back to blue. We need to add the agent until the water sample turns pink and stays pink, be careful because this may happen within the range of one drop. My sample took only 4 drops of reagent to turn pink, hard water area’s may take many more.
Now that the solution has turned pink we can reference the “Alkalinity Table” in the kit by looking at the reading in ml’s on the syringe to find the alkalinity in meq / l. The black piston on the syringe will give you the reading in ml’s.
My alkalinity test took only a few drops so there was 0.92 ml left in the syringe. I referenced this on the alkalinity table which gives me the Alkalinity in meq/L of 0.33
The alkalinity of 0.33 is then multiplied by 50 to calculate the alkalinity in terms of CaCO3 which gives us 16.5.
This means the alkalinity in CaCO3 of my water is 16.5. I can then use this figure to work out the treatment needed using this water treatment calculator.