Water you doing: An intro to water for coffee
6/27: soft launch for feedback gathering, this post is incomplete
“The quality of water you use for your coffee is important.”
You nod your head at how obvious and intuitive the above statement is.
And yet, our effort and respect for it doesn’t match the impact it has. We chase the fun stuff, and water is boring.
Coffee nerd up-leveling often looks like this:
Get better beans and grinder, hope things get better
Incorporate a new workflow step, learn more recipes, hope things get better
Buy more toys (dripper, tool, accessory), hope things get better
Repeat
At some point a product for water might sneak in as a fun purchase, and then an “oh wow” moment - water is a game changer. In order of making it to market - Third Wave Water, Aquacode, Lotus Drops, Apax Labs.
It’s as big or even bigger than the a-ha moment when you try your first high-clarity grinder.
But water is just… so un-sexy.
This post hopes to disrupt that pattern and bring water dialing earlier into your coffee nerd journey. And we’ll do it without reliving chemistry class.
This time-period relevant image summarizes the overarching point.
New York’s magical tap makes the best pizza and pretzels. The river water in Scotland makes their eponymous Scotch whisky - why though?
The magic in a certain water source is not in the pH, it’s not the TDS or just the water being hard/soft, and it’s not using a Brita filter - it’s the breakdowns of various minerals in the water supply.
Some concentration of one mineral, let’s say calcium, and some concentration of another mineral, let’s say magnesium, adds up to make water of a certain composition of mineral ratios. That breakdown may or may not be suitable for specific applications like making bread, brewing beer, and especially brewing coffee
But what if I told you that the “perfect’ water for pourover might be a bad choice for espresso? The “right” water, of course is preference-based, but there’s no single water that suits all coffees or brew methods, which is why we’re here, to take control and make the water for the coffee we want to drink.
Some mental justifications for why we may not want to deal with water:
It’s annoying.
My water source is bad and it’s expensive to change filters often.
It’s just coffee. I don’t want to get a degree in chemistry.
I already have a filter system, isn’t that enough?
My tap water is already soft.
And that’s what we’re here to challenge - it’s not good enough.
The money you spend on expensive beans and equipment and the time and effort spent dialing in new recipes, they will be limited by the composition of minerals in your water.
I am very guilty of this myself. In my first year of coffee as a hobby, I ordered the importance of variables like this (descending):
Beans (big effect) > grinder (big) > recipe (big)> brewing gear (drippers, espresso machine) (medium), water (small)
and I’d now suggest it as:
Beans (big effect) > water (big) > grinder (medium) > recipe (small) > brewing gear (small)
Put another way, you could’ve spent less money to get really far if you invest effort in water and beans early on.
Step 1: Predictable water
Your tap water probably fluctuates throughout the dry and rainy seasons.
You can download your municipal water report, but it’s likely a headache to comprehend. It’s easier to start from 0TDS water with no particulates, then re-add minerals.
Option 1: Culligan ZeroWater
Pros: Shockingly effective at making 0TDS, or basically distilled water. Comes with a basic, good-enough TDS testing pen.
In comparison, a Brita filter may take 100TDS water and bring it down to 40TDS, maybe down to 30 if double filtered; there’s physical limit to its porosity. Zerowater is simply a more capable filter.
Note: TDS pens are only useful for broad strokes and hot/cold water temperatures affect the reading. It is useful to tell you if the filter is failing and a roughly how hard your water source is.
Cons: Slow to filter compared to Brita since it’s doing way more work. Filter lifespans are obviously shorter if your input water source is hard.
For reference, I make around 8-10 gallons a month for coffee. My tap fluctuates between 20-150TDS throughout the year, and my filters last roughly 8 months.
Option 2: Purchase jugs of distilled water
Pros: If your tap water source is known to be bad, this may be cheaper than replacing Zerowater filters every month or so.
I’d suggest trying buying a couple jugs to start out and be convinced that messing with water is worthwhile
Cons: Plastic waste, especially for pourover/filter drinkers. Limited availability in certain countries/regions. Not all distilled water is the same in being true 1gal or Option 2: Purchase jugs of distilled water
Option 3: Reverse-osmosis (RO) + remineralize
Pros: You might have this set up in your house already. Once set up, regular use is seamless until it needs seasonal re-dialing.
Cons: An expensive, laborious home project all on its own. Still needs to be seasonally dialed and measured to understand it as a baseline for further remineralization. Possibly not worthwhile for renters.
Step 2: Minerals
There are two classes of minerals to consider - general hardness (GH) and buffer (KH), which is chemistry we won’t touch on here.
Minerals for GH: Epsom salt (magnesium sulfate, (MgSO4), calcium chloride (CaCl2)
Minerals for KH: Baking soda (sodium bicarbonate, NaHCO3), calcium bicarbonate (Ca(HCO3)2), potassium bicarbonate (KHCO₃)
I recommend starting out with epsom salt and baking soda, as those are the most likely you already have on hand. Different minerals will have drastically different effects on flavor, but it’s more important to start somewhere than overcomplicate at the start.
You’ll need what’s effectively a drug dealer’s scale that goes down to 0.001g. Here’s a link to one. Expect to pay around $15, and ideally it comes with a dosing tray.
Step 3: Starting recipes
This is an introductory set of first recipes to try for light roast coffees; it should not be considered an ending point.
Pourover:
60GH/20KH (60 parts general hardness, 20 parts buffer)
In 1gallon of 0TDS water, mix 0.56g epsom salt and 0.17g baking soda.
Espresso:
60GH/90KH (60 parts general hardness, 90 parts buffer)
In 1gallon of 0TDS water, mix 0.466g epsom salt and 0.572g baking soda.
Important note - This is a proof-of-concept and can cause scale in pump-driven espresso machines long-term. While manual machines like Flair are fine, electric machines like Brevilles should use non-scaling water recipes like Dr. Pavalis water - 0/50, or 0.318g baking soda per 1gal water, and post-mineralize for GH, covered in step 4.
Mix well, let the minerals even out for a few hours, and try a brew side by side to what you’d been doing before (perhaps easier on pourover than draining an espresso water tank).
Alternatively, you can use products like Third Wave Water (TWW), Aquacode, Lotus Drops, or Apax labs. If using TWW, I personally find the default formula way too concentrated, so I suggest diluting 1 sachet into 2 or 3 gallons for light roast coffee brews. These are essentially expensive proxies to figuring out the ratio of minerals like in the above recipes.
Step 4: Next steps before going down the rabbit hole
If you’ve reached this step, you might be convinced! If you’re itching for something else to try, here’s a couple suggestions featuring other minerals:
Pourover water recipe for washed coffees:
40/15 (40 parts general hardness, 15 parts buffer), this time using Calcium chloride for GH, and other bicarbonates for KH.
In 1gallon of 0TDS water, mix 0.17g calcium chloride and 0.06g potassium bicarbonate or calcium bicarbonate.
This recipe may highlight floral, delicate qualities vs. the comparatively juicy and fruity characteristics in the recipe in step 3. Different, not necessarily better. Not a recipe I’d personally reach for with funkier, processed coffees.
Espresso:
20/60 (20 parts general hardness, 60 parts buffer)
In 1gallon of 0TDS water, mix 0.084g calcium bicarbonate and 0.380g baking soda. Again, note that for pump-driven electric machines, this water may cause scale and isn’t an appropriate long-term solution.
I’d suggest this formulation for “high clarity” burrs such as the 64mm SSP multi-purpose to tone down the intense acid-punch of the above 60/90 recipe in step 3.
Other thoughts:
You should expect that different combinations of beans and grinder burrs benefit from revisiting the water. If you drink mostly washed Colombians on the same grinder, you can probably stick to one water.
There are many right answers. Some mineralizations may enhance juiciness at the expense of introducing a savory finish. That’s down to your personal preference.
As a loose suggestion, lighter roasts assume a desire for acidity, and likely benefit from lower overall TDS water. But there’s plenty of situations where a light roast could pair well with 100+TDS water.
Bonus: Post-brew mineralization
A surprise: Adding minerals to a brewed cup comes pretty close to if they were in the water during the coffee brewing extraction. This is huge because you can add minerals on the fly and quickly iterate towards your preferences rather than trying 1gal of a certain recipe to decide what to try next.
For espresso brewers, post-brew mineralizing is even more exciting because it lets you use Dr. Pavalis water in your machine, known for being safe on your boilers, but not tasty, and lets you add back the tastiness back by adding the minerals that would be scaling or corrosive to the pipes.
Lotus Drops inherently solves post-brew mineralization by not only being a concentrate for big batches, but also being at a dilution appropriate for single cups.
If you want to DIY something similar, refer to Vortalos’s DIY concentrates guide (thanks Brett!). Make a duplicate to your account, mind the comments on the fields, and adjust for whether you want to make big concentrations for 1gal or lower dilutions for single cups.
“You can make a better brew with a $200 grinder and taking control of your water than with a $2000 grinder and questionable water.”
I wholeheartedly believe this. I’ll bet you… the minerals it takes to make the right water.
The follow-up to this post will be significantly more technical and revisit high school chemistry concepts.
Further readings:
Note - consider that specific recipes in these resources may be dated for modern light roast styles. Don’t assume they are trying to make the same coffees you are!
Apax labs loose theories on impacts of specific minerals (take with a big grain of… salt on the flavor impacts)