Filtering Hamilton’s Tap Water (For Home Brewing)

[Having discovered new information, the data from this post has been revisited here.]

Today I tested my home brewing water with my titration kit. I also tested my tap water again for comparison. I wanted to post the results online in case anyone finds them helpful.

My home brewing water is simply tap water filtered through a Brita pitcher filter. The filter is currently about a month or two old. (Ew. Gross. Yeah. Whatever.) The pitcher has been flashing the “change soon” light for a couple of days, but has not yet flashed the “change” light. (See? It’s fine.)

I used the Red Sea Pro Test titration kit. I followed the same procedure as I did here, except this time I rinsed my sample vials and sample syringe with tap water before measuring the tap water, and with Brita filtered water before measuring the Brita filtered water.

Yellow rubber gloves were worn, and titration ensued.

Here are my results:

Tap water – Mg: 8-12 ppm, Ca: 32.5 ppm, KH: 111 ppm
Brita filtered tap water – Mg: 12 ppm, Ca: 27.5 ppm, KH: 39 ppm

There are a few things I would like to point out.

Firstly, the tap water was quite consistent with the samples from my first experiment. This is good to see. Consistency = more frequently good coffee.

Secondly, the GH. GH stands for general hardness, the “G” coming from “general”, and the “H” coming from “hardness”. Brilliant. General hardness is our calcium and magnesium content combined, in ppm. According to today’s measurements, our GH is in the 39.5 ppm to 44.5 ppm range for both waters. It’s a bit low. We know from Water For Coffee that we want our GH to be 50ppm or higher for ideal extraction capabilities.

It also looks like the Brita filter may have lowered the calcium content just a little bit. I don’t want to make any major conclusions about this. However, the Brita website says that it does reduce the concentration of calcium and magnesium. And it may have put us just a bit further off from the 50 ppm GH minimum.

Thirdly, the KH – carbonate or temporary hardness. This one I am willing to give a little more weight to. This is more in line with other results I’ve had measuring Brita filtered tap water. It is also a pretty drastic shift. And it is a step in the right direction.

As I mentioned in my last post (I’m just going to keep linking you to that), we also know from Water For Coffee that too much carbonate hardness can leave coffee tasting flat and chalky. 111 ppm is probably going to be too much. At least according to Colonna-Dashwood and Hendon, the authors of the book. And they know their stuff.

Luckily, the Brita filter brings Hamilton water down to 39 ppm, a much more reasonable KH level. Reasonable, but not ideal. As consistent as it is, the water composition will vary slightly day-to-day. Today the KH happened to be at a point where it would be ideal – if the water had a higher GH, in the 50 ppm to ~65 ppm range. It’s about balance. Even if we had 50 ppm in GH, our KH might fluctuate a little bit tomorrow and put us off of ideal water composition. At these low levels of GH and KH there isn’t a lot of leeway.

However, the Brita filter does take Hamilton water from less-than-acceptable to acceptable. It’s progress. And my coffee is tasting pretty good at home. Actually, quite good, more often than not. I guess it can only get better.

I will keep experimenting with ways to have better brewing water at home. For now, the Brita filter is doing pretty well and is a definite step in the right direction for Hamilton home brewers looking to take their brew game to the next level.

I’d love to hear what people are using for their brewing water. Let me know in the comments below.

[Edit: The KH measurements in this post were originally posted in [ion] as [CaCO3]. However, since we are more interested in bicarbonate, I have converted those measurements to display ppm as HCO3.]


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