I recently lucked my way into the semifinals of the UK brewers cup by sourcing a truly exceptional coffee, the washed Sudan Rume varietal from the Las Margaritas farm in Colombia (of which we should have fresh crop landing again quite soon). However I now had a problem, I didn’t want to finish last. I actually even had secret ambitions to take home a piece of silverware.
So off I went and threw myself into learning as much as I could about brewing coffee, which for me meant watching a lot of youtube clips of the 2015 Brewers Cup and settling on what I believe to be the most replicable and consistent brewing method; something quite similar to 2015 UK brewers cup champion Greg Howell. You can even watch his routine here, or even me mumbling through my speech here.
After settling on my brew methods and coffee that left one thing, something I had been putting off since I began my coffee journey. Water. Lucky enough for myself and you Maxwell Colonna-Dashwood has released quite a fewtalks on youtube on the subject which combined with the second half of his and Dr Christopher Hendon’s book really helped break water down into something simple and easy to understand. And now I am going to try dumb it down even further.
In terms of coffee, Maxwell explains in his book that there are three mineral components that affect flavour and extraction in a brew:
Calcium (Calcium chloride CaCI2 or calcium sulfate CaSO4 Gypsom salt)
Calcium pulls flavour out of your coffee grounds and into your final cup but can also cause scale build up inside your machine if present in large quantities with bicarbonate present.
Magnesium (Magnesium chloride MgCI2 or Magnesium Sulfate Epsom salt)
Does much the same job as calcium, won’t cause scale and potentially extracts more florals and fruit flavour than calcium.
Buffer (sodium bicarbonate NaHCO3 baking soda or potassium bicarbonate KHCO3)
Buffer regulates acidity, if there is no buffer present the acidity will be too unhinged and vise versa if there is too much buffer that acidity will be turned into bitter dull chalky flavours. If you have ever brewed coffee with london tap water you will know the latter flavours well.
All of the above products are all cheap and easy to find on Amazon/ebay and in an infinite combination of different mixes that will make tasty coffee but I like to keep things simple and roughly speaking, if you have a water that is made up of a 2:1 general hardness (magnesium and calcium) buffer it will make tasty coffee, as long as it is not too soft or too hard. Let’s say below 40ppm is too soft and above 400 ppm is too hard but people out there I’m sure have brewed tasty coffee outside these bounds. Depending on the combination this will drastically affect the way you roast as it affects the way your coffee extracts but I will not go into that right now and that is a whole different rabbit hole, (but have you ever wondered why different regions have differing styles of roasting preferences?).
A super easy way this can be achieved at home is to purchase a 5L bottle of TESCOS Ashbeck spring water and add 1.6g of magnesium chloride, give it a shake and get brewing. Btw that will get you a water of around 75ppm.
To improve consistency you could also make a concentrate and add that to distilled water as Matt Perger explained on Barista Hustle, which I have summarised below:
1) Add 25g Epsom and 8.6g bicarb to 500ml distilled water to create concentrate. Shake.
2) Add 2.5g of concentrate to 500ml distilled water
3) Store the rest of the concentrate for later
4) Brew with your deliciously mineralised and buffered water!
Water for coffee is one of those subjects where you can basically get as geeky as you want. At the max end (all the puns forever) you can use titration kits to test your water and use scientific method to run test and graph out your perfect water bounds. Maxwell and Hendon are releasing another book coming soon which I am eagerly awaiting so keep an eye out for it. Or you can just add a few grams of magnesium to some supermarket water, give it a shake and measure it with a very inaccurate and Cheap TDS reading. It is truly up to you .
OH BTW if you were wondering I did get to take home a bit of silverware, even if it was only for 3rd I was still pretty stoked.