3rd of May 2018
Water matters. All dedicated baristas know this. And not only to the quality of your brew, but also for the lifespan of your coffee machine. In this article—the latest in our series focusing on water for coffee making—we are going to look at some of the current water treatment trends.
Roasted coffee beans contain compounds like lactic acid, citric acid and eugenol. These compounds, which occur in varying levels depending on the beans, are what gives coffee its many complex and distinct flavours. But water is just as complex and varied. Your water source with its different levels of ions like magnesium and calcium can have a massive impact on the taste of coffee.
Some of the minerals in hard water are ‘sticky’—which means they attach themselves to compounds in coffee when it’s brewed. For example, the more eugenol that water retains, the ‘earthier’ the taste of your coffee will be. Magnesium is particularly sticky, meaning that water high in this mineral will tend to make coffee with a stronger taste. Hard water can also contain high levels of bicarbonate, which can lead to bitter flavours. Soft water also contains sodium elements, but without the flavour stickiness of hard water. This means that even using the same coffee beans, you’ll get a much stronger flavor using high-magnesium hard water instead of softened water.
For espresso machines, it is essential to consider is the hardness of your water, and how this can impact functionality. If the source you are brewing coffee with is hard water, over time, the inside of the boiler will fill up with scale (mineral-based deposits) until it is eventually no longer fully functional. On the flipside, if the water is too lacking in minerals, your machine will also struggle to function properly, and this will have a detrimental effect on your brew.
But help is at hand! We are going to profile a few of the current water treatment options open to coffee connoisseurs.
The first option to combat the water hardness and scale buildup issue is to use softened water. The way of creating soft water from hard water is through a process known (perhaps unsurprisingly) as water softening. Softening uses ion exchange technology to remove the calcium and magnesium ions, instead introducing sodium ions into the water. As a result, softened water contains high levels of sodium and bicarbonate ions. In cities with hard water, particularly if the water contains a lot of lime, soft water can be a good choice, as it won’t lead to the buildup of scale in your coffee machine. However, while softened water will certainly help with the scale issue, if used on its own, this type of water can lead to flat tasting brewed coffee.
A recent trend for water, in the modern coffee market, involves reverse osmosis (or RO). Sounds complicated, but really it’s quite simple. And, it can be another effective approach for maintaining the longevity of your espresso machine.
Reverse osmosis is a water purifying technique which use a smipermeable membrane (a biological or synthetic layer that will allow only certain molecules or ions to pass through it). In the process of reverse osmosis, water is put under pressure as it passes through the minute holes within this membrane. Contaminants that are larger than the water molecules are left as waste, while clean water is filtered through. The end result is that large particles (for example: magnesium, copper, sodium and even fluoride) are separated out from the filtered water. However, using water with no minerals will make an overly acidic, low-texture and unbalanced brew.
Now we’re going to look at how the remineralisation process can create the right balance for your coffee and for your coffee machine.
For water that has been softened or had the RO process, remineralisation is important. Remineralisation essentially involves adding back some of the vital minerals which make the water blend correctly with the coffee. There are several popular water treatment products on the market, which add a stable balance of minerals specifically formulated for brewing coffee. These treatments allow baristas to remineralise distilled water using a small amount of pre-mixed solution, adding minerals and hardness. Crucially, the introduction of these elements will make sure the water doesn’t damage your coffee machine.
Another option popular within the food service industry (especially for restaurants and cafes with high volume of customers) involves the use of a water filter system. It’s important that the filter system is capable of chloramine and chlorine reduction to help improve the taste of the water—and, in turn, make the coffee’s flavour more palatable. You also want to be able to filter out other contaminants like cryptosporidium and giardia, which can impact the quality of your water. Also for regions with hard water, it’s advisable to install scale inhibitor cartridges. These will reduce problematic scale build-up from calcium and magnesium found in hard water.
Clearly, finding the right type of water for your brew and for your coffee machine is essential. Over the next few weeks, we will be looking at some of the other water solutions for the inquisitive and experimental barista.