If you are all grain brewing adjusting your water chemistry can have a significant impact on the quality of your beers. In my previous article about adjusting your water for home brewing I mentioned something called a “Salifert Test”.
It may sound technical but really isn’t and what it does is tell us is the alkalinity of your water supply. This alkalinity figure can then be fed into a water treatment calculator. The calculator will then spit out the brewing salts you need to add to your brew and their amounts.
The alkalinity of the water you use for brewing effects the pH of the mash. The pH is important, enzymes in the mash work best in a range between 5.2 – 5.6 and less efficiently outside this range. The pH will also have an influence of the flavour of the finished beer. If the pH is too far out of range it can produce astringency and phenolic off flavours among other unwanted flavours.
Sometimes alkalinity will be written on a water quality report. This 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. Any fluctuations in the alkalinity of your water supply which can vary from day to day will be taken into account.
The Salifert Test you need to buy will test the alkalinity or Carbonate Hardness.
Performing A Salifert Test
The picture below details what comes with the kit. 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 agent 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 areas may take many more.
Now that the solution has turned pink we can reference the “Alkalinity Table” in the kit. Look 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.
The Results – Water Alkalinity
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.
Water Chemistry For All Grain Brewing
Once you have got your to grips with this little test head over to this post on water chemistry and keep on reading. These simple bit of information can dramatically alter the way a finished beer tastes. Give it a go.