Coffee Calculators
TDS Target Calculator
https://www.coffeesizing.com/calculators/tds-target/
Estimate only — not a cupping score, a water lab or a roast profile. Confirm on a test brew.
TDS Target Calculator
TDS is how concentrated the drink is. Extraction yield is how much of the dry dose dissolved. If you want about 20% EY on an 18 g / 36 g shot, the math wants roughly 10% TDS. Set the target, then grind and ratio until the refractometer agrees — or until taste vetoes the SCA window.
Inputs
Results
- Target TDS
- 10.00%
What to look for on a coffee refractometer at this dose and yield.
Recommended gear
Coffee refractometer
Without a TDS reading this target is trivia. Filter and espresso need a coffee-specific unit, not a brewing-salt pen.
Typical range: $80–$400
0.1 g coffee scale
EY math dies if yield is a guessed 36 g. Weigh the cup every shot you intend to measure.
Typical range: $20–$80
Acaia coffee scale
Fast, repeatable yield so the TDS target is not chasing a sloppy 2 g error.
Typical range: $150–$300
Calculation method
Extraction yield percent equals TDS percent times yield over dose. Rearranged, target TDS is target EY times dose divided by yield. 20% EY at 18 g in and 36 g out is 10% TDS. Filter at 1:16 and 20% EY lands near 1.25% TDS — same equation, different brew ratio.
Exact formula
tdsPercent = targetEyPercent × doseG / yieldG. Limits: Refractometer calibration, CO2, fines and temperature of the sample omitted; EY is a window, not a law.
Strength versus extraction
Raising TDS without raising EY means you brewed tighter (less water per coffee). Raising EY at the same ratio means you dissolved more of the dose — grind, time, or water did the work.
Frequently asked questions
Why is my espresso 9% TDS at 20% EY?
Then the yield is longer than 1:2, or the EY assumption is wrong. Plug the masses you actually weighed. Do not mix a 40 g yield with an 18/36 chart.
Filter coffee on this page?
The equation is the same. Use brew water mass as yield for immersion; for percolation, use beverage in the server. Bypass water changes TDS without changing how far the grounds extracted.
Do I stir the sample?
Yes, and let crema collapse. A foam reading is not TDS of the shot.
More in this topic
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From dose, yield, time and a sour–bitter taste call, get a suggested yield, grind direction and a time hint. Taste first; the numbers follow.
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Compute extraction yield and brew ratio from refractometer TDS, basket dose and beverage mass. EY% = TDS% × yield / dose.
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Grind Size Converter
Convert grinder clicks between machines into estimated microns and whether that setting looks like espresso or filter. A map, not a laser diffraction lab.
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Grinder Burr Lifespan Calculator
Estimate remaining burr life in kilograms and days from daily dose, rated life and kilograms already ground. A planning number, not a steel autopsy.