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Review: Peak Water Filter

Peak Water produces awesome coffee water, when it works. Unfortunately, that’s not all the time.

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Asser Christensen

Licensed Q Arabica Grader, M.A. Journalism

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Water is probably the most frustrating aspect of coffee brewing. 

On the surface, it should be simple, but the reality is that it’s such a complex topic. 

I think most coffee geeks sooner or later come to the same realization and end up abandoning plain, old tap water. 

The big question is then; if not tap water, then what kind of water? 

Until recently, there hasn’t been a clear-cut answer. But now, the startup company Peak Water claims that they have come up with the ideal solution. 

Is it really that great? Well, in this article, I’ll share my (mixed) experiences with the Peak Pitcher.

Where to get it?

🇺🇸 Prima Coffee (US)

🌍 Retailers (World)

About Peak Water

Peak Water is yet another crowdfunded coffee startup.

However, this company was founded by barista guru Maxwell Colonna-Dashwood, and chemist turned coffee scientist Christopher Hendon.

This duo is also behind the seminal work “Water for Coffee,” so if anybody should make a game-changing filter pitcher, my money would also be on them. 

The target audience of the Peak Filter Jug is geeky home baristas. Coffee shops typically have big and professional gear to clean their water, but at home, this seems excessive. A smaller solution is needed. Some coffee drinkers swear to traditional pitcher filter brands such as Brita, while others remineralize reverse osmosis water. Both these solutions have downsides.

You might have to change filter every month.

Now, after some delays, the Peak Filter is finally available in most places in the world. 


The first thing you notice when you open up the Peak Filter box is that it’s a slightly unusual-looking product. But that’s meant in a good way. 

The design language is reminiscent of the Colonna brand (they also roast some excellent beans!).

It has something unique about it that makes it stand out compared to other filter pitchers with its subdued grey color and baby blue accents. 

I got the Starter Pack, which includes 2 additional filters. It seems like the most economical options most places.

Overall, I like the look. It’s iconic and recognizable the same way as some of the other flagship third wave products. The jug will look pretty spiffy on your brew station. 

peak spout

However, the design also has a few annoying flaws. For instance, the spout can be a little bit difficult to pour from with its plastic lid. 

Also, the fact that it’s an opaque jug with a big chamber obstructing the view means that it can be unclear how much water you have left. And if you’re using a setting close to 5, it will take a few minutes to filter some fresh water if you have run out.  

The special touch

The main thing that separates the Peak Filter from more generic brands is that it has a dial on the top. This dial allows you to decide the hardness of the water. If the dial is on 5, the water goes through maximum filtration. Most of the TDS will be removed. On setting 1, the opposite is the case; minimal filtration is applied. 

This mechanism is made by having two separate chambers inside a larger filtration unit. 

One of them (the dual-ion resin filter) strips away everything in the water, so all impurities, minerals, and so on. 

the peak dial
Adjust the hardness here. On setting 5 the water is almost pure.

The other filter only uses activated charcoal, which removes impurities and leaves the minerals in the water. 

What you then get is a mix of the two. 

This construction is quite clever because tap water has a varying hardness in different parts of the world (or even regionally).

Somewhere you’ll have to set the dial to 3, and in other places with exceptionally hard water, you will have to get close to setting 5. 

With other pitcher filter brands such as Brita, Dafi, or BWT, you would just get a one-size-fits-all filtration, where you wouldn’t be able to adjust hardness accurately.

There’s a little test strip included in the package, so you can find out what setting you’ll need for your local water. 

This is a good idea on the surface, but in practice, I think it also has a lot to do with what kind of beans you’re brewing. 

For instance, while I was testing the filter pitcher, I had some ultra light roast beans from The Coffee Collective who uses 30 ppm water in all their cafes. Obviously, I got better results by emulating their water rather than going with Peak’s “scientific” recommendation. 

In daily use 

But enough preamble; how does it work in real life? 

My results were mainly excellent. 

First, I compared it to normal tap water with a TDS of around 180. The Peak Jug was a clear winner, and it was not even close. 

Then I compared it to the same water filtered through a Brita pitcher. The Brita can reduce the TDS down to around 100, but with the Peak filter, you have the option to go down even further. 

While the Brita jug does a decent job in places where the water is already soft, it couldn’t compete with the Peak Filter, especially when it came to the abovementioned Kenyan bean from The Coffee Collective. 

Having been a water geek for quite a few years, I found it very intuitive to use the jug and adjust it to different beans. But of course, you can also leave it at the suggested setting and get good results. 

However, after my initial testing, I went to the other side of the country to visit my dad. In his town, the drinking water from the tap is notoriously hard, with a TDS of around 400. This is the case in many parts of Denmark. 

I knew that this was going to pose a more significant challenge to the Peak Filter. At first, the coffee still tasted excellent using tap water, but within 4-5 days, the jug started to develop a very unpleasant, almost fishy smell. This quickly started to become noticeable in the water as well.  

Perplexed, I googled around a little bit, and it quickly turned out that many users faced this issue. 

I reached out to Maxwell from Peak Water to find out more about the problem.

What he told me via mail was that, the fish smell eventually will occur when the filter is used up. A compound known as trimethylamine, which causes the rotten fish smell is then released.

This compound is unavoidable if you want to use de-ionising resin the filter, and is also used by other manufacturers for example ZeroWater.

However, the smell can happen a lot faster in areas with extremely hard water AND a high amounts of silica in the water.

Peak has changed the composition of their filter to achieve a longer life span in those “trouble” areas.

However, judging from the response from some of my followers on Instagram the life span is still not that great, particularly in Copenhagen.

Now, here is the weird thing that I haven’t seen mentioned elsewhere: Instead of changing the filter unit, I bought some cheap bottled water with a TDS of around 110. I ran a few liters through the jug and discarded it. Then I tried to filter the bottled water down to a TDS of around 60. Suddenly, the fish smell was gone, and I got good water out of the filter again.

However, this is also a little bit concerning. Because how can you know whether you live in such an area before investing in the jug? 

The company claims that even with a filtration capacity of only 25 liters, the jug is still a great investment, but I’m not sure I’d agree with that. For me, that’s probably less than a month’s use.

Peak water Filter
It’s minimalist but pretty cool looking.


So there are several big questions you have to ask yourself before buying the Peak Water Pitcher. 

Is it cheaper or comparable to other decent solutions? In some places, RO water works out pretty cheap in the long run.

Even in Denmark, where bottled water is more expensive, you’d be able to get 40 liters for around $15 from Nornir, which is quite decent for coffee.

Peak Water claims that “Moderately hard waters can give a lifespan of 80 litres,”  but in areas with the most extreme water they only estimate around 25 liters per filter.

With the current price in the US, you’d pay approximately $22,5 per filter. So depending on how problematic your water is, it might be cheaper to buy bottled water. 

Of course, you also have to add the cost of the jug and average that expense out over a few years. 

peak inside
The liner inside is babyblue.

It’s an interesting calculation to make, and it will differ depending on where you live based on the local price of RO water and the longevity you can squeeze out of the filter. 

There’s also the UX aspect to consider: 

  • Do you mind dragging gallon after gallon of water home from the supermarket? 
  • Is the convenience of just filling a jug worth some extra pennies (or dollars) each month? 
  • Can your bottled water actually match what Peak is capable of?

The main concern is of course whether you live in an area where the “fish smell chemical reaction” is likely to occur rapidly. Then your money would be wasted. It would be nice if it were possible to test this somehow before spending money on the gadget. 

the verdict: Peak water

On paper, the Peak Water filter jug is the product that I have been dreaming of for years. 

When it’s working, it’s great. The coffee tastes clean and focused, and you even have the flexibility to impact the result in the direction you desire. 

If you live somewhere where the water is only moderately hard, I think this product is fantastic.

However, for the most desperate coffee geeks – the folks living in cities like Copenhagen and London, where the tap water is abysmal – I’m not sure they are better off than before. The ultra-hard water will ensure that you have to change the filter quite often, and it also seems that the “fish smell” issue is more likely to occur in those hard-water areas. 

Of course , you can do what I have been doing recently: Filter bottled water through the Peak to get a longer lifespan while still getting perfect coffee water. But that’s probably excessive and too expensive for more casual coffee geeks.

As always, coffee water isn’t just a one-size-fits-all, but something that you have to tailor to your geological circumstances as well. So if you’re still desperate and confused, then be sure to check out my big coffee-water post here and find an ideal solution for you. 

Where to get?

🇺🇸 Prima Coffee (US)

🌍 Retailers (World)

Photo of author
Asser Christensen

Hello, and welcome! I'm the editor & founder of this site.
I have been a coffee geek since I started home roasting more than a decade ago. Since then, coffee has taken me on countless adventures: From ancient coffee ceremonies in Ethiopia to the volcanos of Sumatra.
My background is in journalism, and today I'm also a licensed Q Grader under the Coffee Quality Institute.