Water for Coffee Part II
Let’s get right back into it. Water is hugely important for brewing coffee and it is often an overlooked factor which is crazy when you consider it makes up 98% of most black coffees.
Before we get into any solutions or answers I want to highlight what components of water, simply put, make our coffee taste good or bad. There are 3 major aspects of water that we are interested in when it comes to getting the best results for our coffee. They are:
- Mineral Ions (Calcium & Magnesium)
The Specialty Coffee Association of America (SCAA) has a simple list of standards that water for brewing coffee should adhere to which we mentioned in part I https://sca.coffee/research/coffee-standards
When we refer to pH we are testing how acidic or basic our water is. The range of pH starts at 0 (highly acidic) and goes up to 14 (highly basic), 7 is neutral and ideal for brewing coffee, however the Specialty Coffee Association of America (SCAA) suggests that a range of 6-8is acceptable. The limit value set out for pH in the EU drinking water directive is a designated range of > 6.5 - < 9.5 pH units.
Mineral Ions / Water Hardness
A simple way to measure the mineral make-up of water, as well as it’s salts and metals, is by a TDS (Total dissolved solids) probe. The lower the TDS, the higher quality the water is or the purer it is.
How much bicarbonate is present, also referred to as alkalinity, tells us the ability of the water to maintain a neutral pH (7).
This website is a great tool to give you an unnecessarily detailed breakdown of the water quality in your area. This will give you by far the most accurate results rather than going out there and purchasing probes and indicators which will ultimately end up in you scratching your head and possibly more confused.
So your tap water sucks? What can you do?
We’re not going to even go there with commercial filtration systems or reverse osmosis systems as they are outrageously expensive and unnecessary for home use. We’d also suggest avoiding distilled water on it’s own as it is actually too pure and will leave a lot of desired flavours behind.
Domestic filtration systems
I’m sure we’re all familiar with the Brita filter. While it does do a little softening and filters out unpleasant flavours like chlorine it’s not highly effective. This would be useful for someone who has slightly hard water and wants to improve the flavour of their coffee a smidge. Now this ties in nicely with some pretty exciting news, we plan to stock a brand new home water filter system specifically designed for coffee. The Peak Water jug looks like a Brita that was designed by Wayne Enterprises, and it was set up by the great people from Colonna Coffee - who literally wrote the book on Water For Coffee. It comes with a simple test kit and you can compare your results with their recommended standards. The coolest part is that you can adjust it to your taste! This will hopefully be available on the Brew Box website from the end of April/early May. Check out their website for more info https://peak-water.com/
Nice for us, it’s EU legislation that all bottled water must have a breakdown of its mineral composition on the label. I have used Volvic on multiple occasions and it’s pretty perfect for brewing coffee due to it’s fairly low mineral content and neutral pH. In a litre of Volvic water you can expect 12mg of Calcium and 8mg of Calcium. Tesco’s Ashbeck brand comes in a close second if you don’t want to splash out. Now while this water is awesome, I can’t in good faith recommend that you regularly purchase plastic bottles because it is so, so wasteful.
You might think that this is all nerdy nonsense. Maybe you’re one of the lucky ones and you’ve never had any issues with your tap water for brewing! Put there’s a couple of exercises I would highly recommend if you are up for it. First thing you can do is brew a coffee as you normally would from your tap water or filtered water. Then I would try to be as precise as possible when replicating that brew but swap out your water for some Volvic water and taste the results. Another interesting test would be to ask your favourite roaster or cafe for some of their filtered water that they use for brewing/cupping/espresso. Now they might tell you where to go or ask for a small charge but it would be really cool to see people in the industry doing this in the near future!
If the water in your area is really hard this means it will be very high in minerals absorbed from rock and soil. It’s also important to note that hard water, when heated, results in a build up of limescale which can damage and even break our equipment if not treated.
If you’ve ever noticed a build up of white particles in your kettle this is a big tell-tale sign that you’ve got hard water. If so, get something like a Brita which will do a little softening, regularly descale your kettle/coffee gear that heats up water, and always use fresh water - never use water that’s been sitting or previously boiled.
Ultimately, by filtering your water in some way you will improve the taste, flavour and aroma of coffee, and who doesn’t want that?
Home water recipes
This… Is where we get super nerdy, so I’m gonna stop right there and get into this in part III for all you geeks. In the next chapter we will discuss how you can carefully create the perfect water for coffee - yay!