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A Whole New Water World - A Peak Water Review

Updated: Dec 30, 2020

Last edited 30 December 2020

I haven’t been this excited about a home brewing tool for a long, long time. The Peak Water jug has arrived and it has handed greater control to the coffee brewer.

This article is a short review of using the product without going into too much depth about the science of water and extraction. My previous posts about water, and taste experiments discussing hardness, Total Dissolved Solids (TDS) and PH do that. Here we focus on the benefits of using the Peak Water jug and how it can aid in understanding one of the great variables in brewing coffee.

Peak Water Design

The design shape and colour is simple. It feels somewhat flimsy and for my particular jug, the lid does not fit snugly. However, this has not impacted the filtration process or the pouring. It’s a minor bug bear but the main consideration is how it works.

There is a dial on the lid with numbers 1 to 5 and settings in between. Depending on the hardness (calcium and bicarbonate in Peak Water’s definition with the product) of your water (I’m currently based in Essex with tap water counting above 360 TDS and a hardness of around 180 – High and Hard), you set the dial to 5 to remove more hardness and 1 keep the water relatively mineral rich.

Not everyone has a TDS measuring instrument but this is not so important, considering hardness has a bigger impact on flavour. The Peak Water comes with a water hardness testing strip which, when dipped in your regular tap water, reveals its hardness. The manual then gives recommendations, based on the results, of where to set your dial. The instructions are simple and easy-to-follow. There is also further information for experimenting with water depending on the roast/variety of your coffee and tea. This is excellent added value.

Setting my dial to 5, it brought the TDS down to 80. This just tells us the water chemistry has changed, not necessarily if it is good for brewing coffee. It is clearly a significant change. At setting 3, the TDS count was 200.

Finally, Peak Water advises the filter should be changed at least every two months to avoid drinking a build-up of bacteria. If filters cost £12-16, I think this is a worthwhile investment, particularly if it means I no longer need to keep buying Ashbeck bottles from Tesco, contributing to plastic waste.


This control gives a much greater level of freedom in experimenting with water. Using tap water or shop bought bottles, you’re generally stuck with its values. A regular water filter will change its quality and if you’re in a hard water area, it generally makes it better for brewing. However, there is no easy way to control its values. On the other end of the spectrum you could buy or make distilled water, adding minerals and bicarbonate. With this though, you lack the speed at which you can change your water and it’s quite the investment. The Peak Water jug solves these problems with great speed.

As coffee’s majority and active ingredient (the solvent) is water, its makeup has a huge impact on the tastes and flavour in your cup. I personally think water is the most important variable for the home brewer, along with grind uniformity.

For example, high levels of bicarbonate cancel out acidity, and so does none. Low levels of magnesium mean a less sweet, flavourful cup. I tried four types of coffee with tap water and varying settings on the jug:

Lavazza Italian Roast – I set my dial to just under 3 to maintain mineral richness. Compared with a tap water brew, the coffee tasted much cleaner and less bitter. With higher settings on the dial (relatively ‘empty’ water), the flavour and body faded.

Squaremile Kenyan Medium-light Roast – Setting the dial to just under 4 gave the best results. It allowed me to taste the delicious apple and berry acidity of the Kenyan coffee, completely missing from the tap water brew. Massive improvement.

Colonna Congo DR Medium Roast – My preferred setting was just above 3. It produced the most flavourful cup and a long, pleasant aftertaste.

Nespresso Roma pod – Setting the dial to 3.5, I actually found acidity in a dark-roasted Nespresso pod! The cleanliness was much improved, with a significant reduction in bitterness.


I love the ability to manipulate water and the dial has already proven its worth in just a week of use. It should be noted, people become very used to their local water and may at first be less appreciative of changes. I poured out three cups of water and had my younger brother taste them. One with tap water, and others with Peak Water settings 3 and 5. Unsurprisingly, he preferred the tap water (the only water he drinks).

But for coffee (and tea), the changes Peak Water has allowed is a massive improvement for home brewing. The results are also noticeable for coffee ‘lay people’, with family members describing changes in the flavour of their coffee in positive terms.

This, and the reduction in plastic waste, are massive benefits delivered with the arrival of Peak Water.

Edit: I advise to keep your Peak Water jug in the fridge. This will slow down bateria growth in the filter and help it last longer. When your boiled water smells like the seaside, it's time to change your filter.

I am in no way affiliated with Peak Water or Colonna coffee. This article is for the benefit of coffee lovers.


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