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Learn how water chemistry shapes espresso taste. Get key specs for TDS, hardness, and pH – and tips to stop scale and corrosion.
Espresso might start with beans, but its flavor lives or dies by water. Since espresso is over 90% water, even small chemical shifts – minerals, pH, or disinfectants – can transform your shot from smooth to sharp. (Remember that time when your Americano smelled and tasted like it came out of a swimming pool? Yeah, urrrrgh!)
The challenge? Water isn’t constant. It varies by city, season, and even municipal treatment method.
According to the U.S. Environmental Protection Agency (EPA), over one in five Americans receive chloramine-treated water, which behaves very differently from chlorine during filtration.
This guide breaks down what espresso-friendly water looks like, how to hit those targets, and how to keep your machine happy – without needing a chemistry degree.
Think of this as your spec sheet when talking to filter vendors or setting store standards.
These guidelines come directly from the La Marzocco Water Specification PDF and align with the Specialty Coffee Association (SCA) brewing water standards.
Here’s a quick glossary minus the jargon – so your whole team can follow along.
Total Dissolved Solids (TDS) measures the overall concentration of dissolved minerals.
The SCA recommends a target TDS of 150 mg/L (acceptable 75–250 mg/L). Too low makes espresso taste hollow; too high muddies flavor and promotes scale.
Hardness mainly reflects calcium and magnesium levels. These minerals enhance body and sweetness, but excess hardness leads to scale buildup, restricting flow and heat transfer – a major cause of service calls (La Marzocco).
Alkalinity buffers water’s pH, protecting both flavor and metal parts.
As Urbans Aqua’s SCA water overview explains, 40–80 ppm alkalinity helps prevent corrosion while keeping acidity balanced.
The pH of water measures how acidic or basic it is, on a scale where 7 is neutral. Espresso machines (and taste) prefer water that’s slightly neutral – around 6.5 to 8.0.
Too acidic, and you risk corrosion; too basic, and shots taste flat. The Specialty Coffee Association (SCA) recommends staying near neutral for both balanced flavor and equipment longevity.
Both disinfectants kill pathogens, but behave differently in filters.
More details in the EPA Chloramine Fact Sheet.
Not to be confused with chlorine – chloride is a salt ion that corrodes stainless steel.
According to La Marzocco’s Understanding Water guide, anything above 30 ppm chloride increases the risk of pitting corrosion. Reverse osmosis (RO) is the safest corrective measure.
Water that’s too pure (distilled or straight RO) can make espresso taste flat and even confuse level sensors, since ultra-low conductivity affects electronic probes (La Marzocco, 2018).
On the flip side, high-hardness water drives scale buildup, increasing energy use and decreasing temperature stability.
And excessive chloride quietly corrodes internal steel parts.
Staying within the manufacturer’s range – or the SCA’s “Gold Cup” zone – gives the best balance of sweetness, body, and machine life.
No one filter is “best”. The right choice depends on your starting water.
(Source: EP Coffee/Shopify Water Guides)
(Source: EP Coffee/Shopify)
If any of these sound familiar, check your readings this week.
Did You Know? Even reputable pitcher filters often do nothing for hardness or chloride. They can make water smell/taste nicer without putting you inside machine‑safe ranges. Testing is what separates guesses from control.
Log readings so you can trace any taste or maintenance shifts. Software like Moqa or other CMMS platforms can schedule reminders automatically.
1. City Water (Chlorine)
2. City Water (Chloramine)
3. Well Water
Myth 1: “Distilled or RO water is best.”
→ False. Machines and coffee need some minerals. Ultra-pure water causes sensor errors and corrosion. (La Marzocco, 2018)
Myth 2: “All carbon filters remove chloramine.”
→ Only catalytic carbon does. (See WQA Chloramine Fact Sheet)
Myth 3: “TDS tells me everything.”
→ TDS is a total – not a breakdown. Always test hardness and alkalinity. (SCA Standard)
We know the pain‑points: different municipalities, changing disinfectants, and uneven outcomes. If you operate several stores, consistency starts with documentation.
Set a safe window, match filtration to your disinfectant (chlorine vs. chloramine), and log three numbers once a month. That’s it. Fewer service calls, fewer “why does this taste different?” conversations, and more calm mornings.
Following OEM and SCA guidelines will keep your espresso tasting consistent and your machine running smoothly.
If you’re rolling this out across multiple stores, Moqa can schedule the checks, store the readings, and flag the outliers – so water becomes one less variable in your day.
Ready to simplify espresso upkeep? Book a free demo today and see how effortless water testing and machine care can be with Moqa.
TDS 90–150 ppm, Hardness 70–100 ppm, Alkalinity 40–80 ppm, pH 6.5–8.0. (Source: La Marzocco Water Spec)
Avoid pure distilled or un-remineralized RO water – it can corrode parts and cause detection errors. Always remineralize or blend.
Consult your EPA Consumer Confidence Report or local utility website. If yes, install catalytic carbon filtration.
Test once during setup, then monthly. Track trends – utilities sometimes switch between chlorine and chloramine seasonally.
Depends on your source:
High chloride (> 30 ppm) causes stainless-steel pitting. Use RO filtration (La Marzocco).
Sodium-exchange softeners can raise sodium and alter corrosion behavior – verify your treated water stays within spec.
Yes. Utility blending and disinfectant changes can shift TDS and pH. Regular testing helps maintain flavor consistency.
Too-hard water = scale. High chloride = corrosion. Wrong filter = off-flavors. Proper water reduces service calls dramatically.
No single number – just a safe window defined by your OEM and SCA standards. Tune flavor within that range.
