calculators.coffee by Timberline Coffee School

Brew Strength Calculator

Enter three brewing variables and solve for the fourth. Dose, beverage mass, TDS, and extraction yield , with SCA range feedback.

Solve for

Final volume in the cup

SCA ideal: 1.15–1.45%

SCA ideal: 18–22%

Result

15.00g coffee dose

Dose

15.0 g

Beverage

240 g

TDS

1.25 %

Extraction Yield

20.0 %

Brew Ratio

1:16.0

Water in (est.)

243 g

TDS: SCA ideal range (1.15–1.45% TDS)
Extraction: Ideal extraction (18–22% EY)

Last updated

How to Use This Calculator

Choose which variable you want to solve for, then fill in the other three. The calculator uses the SCA brewing formula to find the missing value and tells you whether your TDS and extraction yield fall inside the ideal range.

Use it for recipe planning before you brew: if you know your target TDS and extraction yield, it will tell you exactly how much coffee to dose for a given beverage volume.

The Four Brewing Variables

Every cup of filter coffee is described by four interrelated numbers: the coffee dose in grams, the beverage mass in the cup, the TDS percentage, and the extraction yield percentage. Fix any three and the fourth is determined by the formula.

TDS (total dissolved solids) tells you how concentrated the coffee is. The SCA ideal range for filter coffee is 1.15 to 1.45 percent. Below 1.15 percent tastes watery. Above 1.45 percent tends toward heavy or astringent.

Extraction yield tells you how much of the coffee's mass was dissolved into the cup. The SCA ideal range is 18 to 22 percent. Under-extracted coffee (below 18 percent) is often sour, thin, or underdeveloped. Over-extracted coffee (above 22 percent) is often bitter, dry, or harsh.

The formula: TDS% = (dose_g × EY%) / beverage_g. All four variables are related by this single equation.

Frequently Asked Questions

What is TDS in coffee?

TDS stands for total dissolved solids: the percentage of your brewed coffee that is dissolved coffee compounds rather than water. A TDS of 1.25% means 1.25g of dissolved solids in every 100g of beverage. The SCA ideal filter brew range is 1.15–1.45% TDS. Below 1.15% tastes watery; above 1.45% tends toward heavy or astringent.

What is extraction yield?

Extraction yield is the percentage of the coffee dose that was dissolved into the beverage. If you start with 15g of coffee and 3g of solids end up in your cup, you extracted 20%. The SCA ideal range for filter coffee is 18–22%. Under 18% is under-extracted: often sour, thin, or underdeveloped. Over 22% is over-extracted: often bitter, dry, or astringent.

What is the formula this calculator uses?

The core formula is: TDS% = (dose_g × extraction_yield%) / beverage_mass_g. Rearranged: dose = (beverage × TDS%) / EY%; beverage = (dose × EY%) / TDS%; EY% = (TDS% × beverage) / dose. This is the standard VST/SCA relationship between the four brewing variables.

Why does 'solve for dose' give a higher number than I expected?

The calculator gives you the dose needed to hit both your target TDS and your target extraction yield simultaneously with your specified beverage volume. If the result seems high, check that your TDS and EY targets are both in the SCA ideal ranges (1.15–1.45% TDS, 18–22% EY). Using a very high TDS with a low EY naturally requires a large dose.

What is 'water in' vs. beverage mass?

Beverage mass is what ends up in the cup. Water in is the total water you pour into the brewer. It is higher because coffee grounds absorb roughly 1.5–2× their weight in water (absorption varies by grind size and freshness). The calculator estimates water in as beverage mass plus 20% of dose weight, which is a reasonable approximation for most filter methods.

Related Calculators