Coffee Calculators
Descaling Frequency Calculator
https://www.coffeesizing.com/calculators/descaling-frequency/
Estimate only — not a cupping score, a water lab or a roast profile. Confirm on a test brew.
Descaling Frequency Calculator
Scale is hardness minerals, mostly calcium carbonate, dropping out as water heats. Harder water and more shots fill a small boiler faster. This is a crude capacity model so you descale before the PID lies and the group cools. Soft barista water stretches the interval; 180 ppm tap water does not.
Inputs
Results
- Days until descale
- 30days
- Shots until descale
- 240
The Result is indicative and educational. It does not constitute a design, a technical opinion or medical advice and does not replace calculations or verification by a person with the appropriate qualifications and authorisations. Before purchase, installation or use in practice – in particular in electrical installations – the Result should be verified by a qualified specialist. Details: Terms of Service, point 4.
Example products
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Descaling powder
Use what the machine maker allows. Generic powder is fine on many boilers; warranty pages are not this calculator.
Typical range: $10–$25
Water filter pitcher
Lower GH before it becomes scale. Filtering is cheaper than a heating element.
Typical range: $20–$50
Espresso machine
If you are descaling weekly, the water is the problem, not the calendar. Fix GH, then enjoy the machine.
Typical range: $400–$2,500
Calculation method
A reference machine at 180 ppm, 8 shots/day and 300 ml is treated as a 30-day descale. Your days scale inversely with hardness and shots, and grow in proportion to boiler volume, because a bigger boiler holds more scale before it chokes: a 1 L boiler at the same 180 ppm and 8 shots reaches 100 days. Shots until descale is days times shots per day. Soft 80 ppm water at the same habit lasts longer; twice the shots cuts the calendar in half.
Exact formula
scaleIndex = hardnessPpm × shotsPerDay × (300 / boilerVolumeMl). daysUntilDescale = clamp(7, 365, 43200 / scaleIndex). Reference: 180 ppm, 8 shots, 300 ml → 30 days. Limits: steam vs brew boiler, temperature, the carbonate share of the hardness and ion-exchange softening are omitted; the machine’s manual beats this guess.
Warranty water
Many prosumer manuals cap hardness. If you are outside it, the frequency number is how often you pay for that choice.
Frequently asked questions
I use recipe water at 80 ppm. Still descale?
Yes, less often. Soft water still leaves some scale, just more slowly. Stretch the interval; do not delete the task.
Dual boiler?
Enter the boiler you care about, or run twice. Steam boilers often see more concentration from makeup water.
Backflushing vs descaling?
Backflush detergent is oils and the group. Descale is minerals in the boiler. They are not substitutes.
More in this topic
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Build brewing water from target GH and KH as ppm CaCO₃. Get Epsom salt and baking soda in milligrams and grams for a chosen volume.
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Compare water KH to brew TDS for a simple buffer index and whether acidity is likely muted. Alkalinity fights acids; it does not erase roast.
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Add bypass water to a brewed batch to hit a lower target TDS. Beverage mass goes up; extraction yield of the grounds stays where it was.
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Water Hardness & Alkalinity Calculator
Convert GH and KH from ppm as CaCO₃ into German degrees and their ratio. Useful when a test kit and a coffee recipe disagree on units.