When people talk about great coffee they start with the beans: origin, processing, roast profile, brew method. At Beanlytics Craft Coffee, a specialty roastery in Richmond, BC, those details matter a lot, but another variable decides whether the cup tastes flat or phenomenal, and it is the one most people never measure: water.

Coffee is 98 to 99 percent water. The minerals dissolved in it decide how much flavour the water can pull out of the grounds, so the same bag can taste thin from one kettle and sweet from another. In Metro Vancouver that matters more than in most cities, because our tap water is unusually soft.

What water should you brew coffee with?

Brew with water that carries some minerals but not many: 75 to 250 mg/L of total dissolved solids with about 150 as the target, calcium hardness between 50 and 175 mg/L, alkalinity near 40 mg/L, and a pH between 6.5 and 7.5. Those are the Specialty Coffee Association’s figures. Metro Vancouver tap water sits well below that mineral range, so the fix here is adding minerals, not removing them.

Water figures at a glance

Variable	SCA guidance	Our starting point	Metro Vancouver tap, 2024	Why it matters
Total dissolved solids	75 to 250 mg/L, target 150	About 150 ppm	Very low; see hardness and alkalinity	More dissolved minerals means more extraction, up to the point where the cup turns chalky.
Calcium hardness, as CaCO3	50 to 175 mg/L, target 68	50 to 100 ppm	22 mg/L from the Seymour-Capilano plant, 2.5 mg/L from Coquitlam	Calcium and magnesium carry flavour compounds out of the grounds. Too little reads thin and sour, too much reads bitter and scales your kettle.
Total alkalinity, as CaCO3	About 40 mg/L, up to 75	About 40 ppm	21 mg/L, target 20 at both plants	Alkalinity buffers coffee’s acids. Low reads sharp, high reads dull.
pH	6.5 to 7.5, target 7.0	Around 7	8.0 to 8.3 on average, target 8.3 to 8.5 for corrosion control	Matters less than alkalinity. Our tap’s high pH comes with low alkalinity, so it does not flatten the cup the way hard water does.
Sodium	About 10 mg/L	5 to 30 ppm	Not reported in the treated-water table	A little sodium reads as sweetness; a lot reads as salt or soap.
Chlorine	None	None	Present, from disinfection	Chlorine flattens aroma and adds a chemical edge. A carbon filter removes it.

Sources: the SCA Water Quality Handbook figures as the association publishes them; Metro Vancouver’s drinking water quality page and its 2024 Water Quality Annual Report, treated-water averages. The “our starting point” column is where we set our own brewing water in the roastery; it sits inside the SCA range on purpose.

Why water matters more than you think

Extraction is chemistry: hot water dissolves acids, sugars, oils and aromatic compounds out of the grounds. The minerals already in the water decide how well that works. With too few, the process stalls and the coffee tastes sour and thin. With too many, it runs too far and the coffee tastes bitter and chalky. For a roaster, water has as real an effect on the final cup as grind size or brew temperature, which is why it gets the same attention.

The four minerals that shape the cup

Four minerals do most of the work in coffee extraction: magnesium, calcium, bicarbonate and sodium. Each changes the way the coffee tastes and feels.

Magnesium highlights fruity, floral and bright notes, especially in single-origin coffees. In the 8 to 12 ppm range it can make a washed Ethiopian taste sweeter and more aromatic instead of dull or hollow.
Calcium builds mouthfeel and brings out chocolatey, nutty and sweet flavours. Above about 120 ppm it drives over-extraction, leaving harsh, dry or chalky bitterness, and it scales brewers and espresso machines.
Bicarbonate is the buffer that moderates coffee’s natural acidity. In the right range it smooths sharp edges without making the cup taste flat. Too little and the coffee tastes aggressively sour; too much and the brightness disappears into cardboard.
Sodium in small amounts, around 5 to 30 ppm, lifts the perception of sweetness without tasting salty. That is why some coffee-specific mineral recipes include a touch of it.

Most published coffee-water recipes aim for more magnesium than calcium, often about two to one, because magnesium lifts the high notes while calcium fills in the body.

TDS, hardness and alkalinity: the numbers that matter

To make water practical for everyday brewing, think in three measurable numbers: total dissolved solids, hardness and alkalinity.

Total dissolved solids

TDS is the total concentration of minerals in the water, in ppm. It is the quickest indicator of whether water will under-extract or over-extract coffee.

Below 75 ppm: flat, thin, often sour. There are not enough minerals to carry flavour compounds.
100 to 150 ppm: balanced, sweet and full. The sweet spot for most specialty coffees.
Above 250 ppm: bitter, chalky, muddy, and hard on equipment.

The Specialty Coffee Association’s range is 75 to 250 ppm with a target near 150, which is also where most roasters and water researchers land.

Hardness

Hardness measures calcium and magnesium specifically, usually expressed as ppm of calcium carbonate. It is not the same as TDS, which counts every dissolved mineral.

Soft water, 0 to 60 ppm: under-extraction, sour and weak cups. Metro Vancouver tap water lives here.
Our starting point, 50 to 100 ppm: balanced sweetness, clarity and body.
Hard water, above 175 ppm: over-extraction, pronounced bitterness, and scale inside kettles and espresso machines.

Alkalinity and pH

Alkalinity measures how strongly water resists a change in pH when an acid, such as coffee, is added. For flavour, alkalinity matters more than pH itself.

Our starting point: 40 to 70 ppm as calcium carbonate, with around 40 as the ideal.
Below 40 ppm: the coffee can taste sharp or even salty.
Above 70 ppm: brightness fades and the cup goes dull.

Brewing water pH should sit around 7.0, within a workable range of 6.5 to 7.5. Below 6.5 the water is too acidic; above 7.5 it can suppress acidity and nuance, though only when the alkalinity is high as well.

What this means in Metro Vancouver

The region’s water comes off the Capilano, Seymour and Coquitlam watersheds, and Metro Vancouver describes it as soft. In 2024 the treated water leaving the Seymour-Capilano plant averaged 22 mg/L of hardness and 21 mg/L of alkalinity, both as calcium carbonate; water from the Coquitlam plant was softer still at 2.5 mg/L of hardness. Since June 2021 both plants have raised the pH to a target of 8.3 to 8.5 and the alkalinity to about 20 mg/L to protect copper pipes, using hydrated lime at Seymour-Capilano and soda ash at Coquitlam, with carbon dioxide to trim the pH.

For coffee, three things follow. First, the water is far softer than the SCA range, so a pour-over made with straight tap water tends to read thin and sour. Second, the high pH is not the problem it looks like, because the alkalinity behind it is low. Third, the right correction is to add minerals, not to filter them out: a reverse-osmosis system or a softener has almost nothing to remove here. A carbon filter is still worth having for the chlorine.

How water changes the way our coffee tastes

We roast single-origin coffees for clarity, sweetness and balance, so every profile is tuned to show layered sweetness, distinct origin character and a clean finish when the brewing water is right. With very soft water our Ethiopian can taste thin and sour no matter how carefully it is brewed. With very hard, high-bicarbonate water the same coffee turns heavy and muddy and loses the citrus and floral notes the roast was built around. Bring the water into range, TDS near 150 ppm, hardness 50 to 100 ppm and alkalinity near 40 ppm, and the difference is not subtle: more sweetness, more clarity, and the same result every time.

Simple steps to improve your brewing water

Test what you have. An inexpensive TDS meter reads total dissolved solids; test strips read hardness and alkalinity. Write the baseline down.
Compare it with the targets. TDS near 150 ppm, hardness 50 to 100 ppm, alkalinity around 40 ppm, pH around 7.
Add minerals if you are in Metro Vancouver. Mineral packets made for coffee, Third Wave Water being the best known, take the arithmetic out of it: one packet into a set volume of filtered or distilled water. If you prefer to mix your own from magnesium sulfate, calcium chloride and sodium bicarbonate, follow a published recipe and weigh the salts on a scale that reads to 0.01 g; guessing puts you outside the range faster than tap water does.
Take the minerals out if your water is hard. Outside this region, where tap water can run past 250 ppm, a reverse-osmosis system with remineralization brings it back into range.
Remove chlorine. An activated carbon filter on the tap or in a jug is enough. Chlorinated water puts a chemical edge on delicate coffees.

Try it with our Sumatra

If you want a tangible way to taste what water does, brew our Sumatra Mandheling twice. It is a wet-hulled Ateng from the Simalungun and Karo community cooperative, and it cups as fruity orange, gentle herbal earthiness and a smoky finish. Make one cup with straight tap water and one with mineralized water, then pay attention to how the orange lifts, how the sweetness rounds out, and how the finish cleans up when the minerals are in place.

Why water belongs in every coffee conversation

Great coffee is never an accident. It comes from careful sourcing, careful roasting and careful brewing, and water is the bridge between what we design on the cupping table and what you taste at home. Treat it as seriously as the beans and the beans will finally taste the way they were meant to.

Great water deserves great beans.

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Water Chemistry for Coffee Brewing: What Actually Matters