Water continued December 21 2015, 0 Comments

My previous post outlined some of the problems we face with the quality of water at our Roastery. In short, water can influence how a coffee brews and tastes. This in turn makes it difficult to determine whether the characteristics of a coffee are due to the influence of the roasting or the water. Having now determined what constitutes ‘ideal’ water, and having discovered that our water is far from ideal, we have been working on ways to improve the situation.

Ever since we became interested in water back in 2012, we have been looking for solutions; albeit solutions to a problem we hadn’t quite defined correctly. We came to realise early on that we needed to add something to the water and started to look at some remineralising filter options. We tried a couple of different manufacturers, one of which was an off the shelf product and the other a more bespoke product, but each resulted in the same issue. Because the water was flowing through the filter, the degree of remineralisation was determined by flow. The quicker the water passes through the filter, the less it remineralises, and if the water sits in the filter overnight, it can absorb a lot more minerals. This gave a very inconsistent solution, particularly at the Roastery where the espresso machines are used less often.

I think this issue was compounded further by the low mineral content in our water. I have a feeling these filters would work better to ‘tweak’ water rather than to achieve the degree of remineralisation we were looking for.

Earlier this year I began reading ‘Water for Coffee’[1] and it quickly became evident there was a solution which would work at the Roastery, and would offer the consistency we needed. When we take our espresso machine on the road to attend events, we fill 25 litre containers with water and use a pump to generate the pressure we need to operate the equipment. The minerals needed to create ‘ideal’ water are available as compounds, which can be added in varying amounts to our containers in order to produce the desired effect. We now have one of our espresso machines set up with barrels of water, each of which has been remineralised to a specific level through the addition of these compounds. In addition we also have a hot water heater set up in the same way and have installed a tap onto the system to allow us to test and taste the water.

It has taken a bit of trial and error but we have now managed to produce the following water (compared to what exists in the tap):

Tap Water ‘Created’ water
General Hardness [2] 4.8 128
Alkalinity [3] 6.1 48.8
pH 6.95 7.6

To some this may seem a lot of effort for a cup of coffee! However, if you consider the effort we put into searching out our green beans, the care with which we roast them, and the precision we put into brewing a cup of coffee, it makes sense to go the extra mile in respect of the water. It really doesn’t take that long to fill a container and to add some minerals. Creating ‘ideal’ water goes way beyond the search for a great cup of coffee as we are starting to realise the water has an impact on our roasting.

We have a ‘cause and effect’ approach to our coffee roasting. The information we glean about a green coffee bean (origin, altitude, farm, processing, etc) gives us an indication as to how the coffee is likely to taste. Our roasting is an interpretation of the green bean, and is likely to differ to that of other coffee roasters. We taste each batch of coffee we roast and determine whether we need to alter the roast profile as a result. We then need to work out whether those tweaks to the profile have achieved the desired results. All of this is based on how the coffee tastes. Consider then a situation where the water we use is having an impact on the flavour and character of the coffee. We can never be sure whether the resulting taste is as a result of our roasting, or the water. By using ‘ideal’ water we can better determine the impact of changing a roast profile.

We already know that water can add sour and sharp tones to the coffee, and it is becoming clear that the lack of minerals mutes the exciting flavours in the cup. We are also starting to wonder whether the quality of the water might disguise what we consider to be roast taints, such as a ‘roasty’ flavour in the coffee. This could also suggest why darker roasted coffee has such a presence in Cumbria – could the quality of the water be masking much of the roasted and bitter tones in the coffee?

So much of this is at the experimental stage at the moment and a lot of it is based on anecdotal evidence. We’re noticing a lot less channelling when making espresso, and overall there is a much greater consistency in respect of the extraction we can achieve. This seems to be particularly true when using 58mm baskets as opposed to 53mm baskets[4]. Filling barrels with water and adding minerals might be an option at our roastery but is unlikely to work in busier, commercial environments. We are currently looking for filtration methods which do work and will be testing some options in the coming weeks and months. We also need to work on our water/mineral mixture – the amount of minerals needed to lift our water into the ideal zone can leave a slight flavour taint on the water. We need to look at reducing these minerals slighlty to remove this taint, while at the same time keeping the water as close to ‘ideal’ as possible.


  1. Water for Coffee, Maxwell Colonna-Dashwood & Christopher H. Hendon, 2015  ↩
  2. ppm Ca2+ and Mg2+  ↩
  3. ppm HCO3  ↩
  4. We have both La Spaziale (53mm baskets) and La Marzocco (58mm baskets) at the Roastery. In the past we have found it easier to achieve a consistent extraction with the 53mm baskets, possibly due to the increased depth of coffee. With ‘ideal’ water this seems less of a problem.  ↩