calculators.coffee by Timberline Coffee School

Moka Pot Calculator

Dose, water fill, and yield for every moka pot size. Based on Bialetti manufacturer specs.

Basket: 15–17g  ·  Water fill: 150mL  ·  Approx yield: 110mL  ·  Cups: 2-3

Advisory only. Finer than V60, coarser than espresso. Go finer only if you are dialing in for a cleaner cup.

Reduces water to 135 mL. Lowers yield slightly. Useful if you prefer a less concentrated result.

Brew advisory

  • Heat: Medium-low heat. Heat slowly to avoid scorching.
  • Time: 4 to 8 minutes from cold; 3 to 5 minutes from pre-heated water.
  • Stop: Remove from heat when coffee starts gurgling, not sputtering.
  • Tamp: Do not tamp. Level grounds only. Tamping creates over-pressure risk.

Brew Schedule

  1. On Heat

    Place Moka pot on low-medium heat with the lid open so you can watch for the first flow. Pre-heated water in the base reduces brew time and protects flavor.

  2. First Flow

    Coffee should begin rising in a slow, golden, honey-like stream. If it sputters and sprays, reduce heat immediately.

  3. Flow Slows

    The stream lightens in color and slows; this marks the end of the productive extraction window. Keep watching.

  4. Remove from Heat

    Take the Moka pot off heat the moment gurgling begins. The steam and sputtering that follow are bitter and thin. Do not wait.

  5. Cool the Base

    Run cold water over the bottom chamber for a few seconds to stop extraction; pour immediately once flow stops.

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How to Use This Calculator

  1. Select Your Pot Size

    Pick the cup size that matches your moka pot. The basket capacity and water fill are fixed by the hardware; the calculator reads them from the Bialetti manufacturer specs for each size.

  2. Choose a Grind Advisory

    Fine-medium is the standard starting point: finer than a drip basket, coarser than espresso. Switch to Fine only if you are dialing in for a cleaner, less bitter cup and your grinder can hold a consistent setting.

  3. Adjust Fill Level (Optional)

    Check the 90% fill option if you want a slightly lighter result. This reduces the water by 10% and lowers the yield accordingly. Full fill is the default.

  4. Read the Result

    The result card shows your dose, water fill, approximate yield, effective ratio, and serving count. The brew advisory covers heat, timing, and the one rule that matters most: never tamp.

The Moka Pot: Capacity-Constrained Brewing

Unlike ratio-based pour-over calculators, the moka pot calculator works with hardware-constrained inputs. You don’t get to choose a ratio; the basket size determines dose and the water chamber determines volume. What you control is heat, grind, and timing, and those are the variables that separate a clean, sweet stovetop cup from the bitter metallic result that gave moka pots a bad reputation in the 1990s.

The effective ratio for a 3-cup Bialetti (15 to 17 g dose, 110 mL yield) sits at about 1:7.3. That is stronger than filter coffee, weaker than espresso. It is not a substitute for either. The flavour profile is its own thing: more body than a pour-over, more bitterness than a French press, less sweetness than a well-pulled espresso. Use it to make Americanos, add it to hot milk, or drink it straight in a small cup.

The moka pot does not scale particularly well for large groups. If you need more than 6 cups, you are better off with two moka pots running in parallel than one large one. Heat management gets harder on a big pot and the results are less consistent.

Heat, Grind, and Timing

Heat slowly. Medium-low on the stovetop, or pre-heat the water in a kettle to reduce the time the grounds spend over direct heat before extraction starts. High heat forces extraction too fast and drives bitter compounds into the cup.

Grind medium-fine, finer than a drip basket, not as fine as espresso. Espresso-fine grounds create too much resistance in a moka pot, which can cause pressure to build unevenly and make the valve kick. The reference grind is somewhere between table salt and fine sea salt. Never tamp. The grounds go in level, not pressed. Tamping creates a compressed puck that the moka pot’s 1 to 3 bar of steam pressure is not designed to push through evenly.

ParameterRecommendationNotes
Pressure1–3 bar (steam)Not espresso (9 bar). Different extraction chemistry.
Grind sizeFine-medium to fineBetween table salt and fine sea salt. Never espresso-fine.
Heat levelMedium-lowSlow heat reduces bitterness. High heat is the most common mistake.
Brew time4–8 min (cold start)3–5 min from pre-heated water. Stop at a gurgle, not a sputter.
TampNeverLevel grounds only. Tamping creates over-pressure and uneven extraction.
Water fillBelow safety valveThe valve is a pressure-relief device. Do not block or overfill.

Pressure Safety

The moka pot safety valve is a pressure-relief device, not a maximum fill indicator. Overfilling the lower chamber, tamping the grounds, or blocking the valve can result in failure under steam pressure. Fill water to just below the valve. Level the grounds without pressing. Keep the valve clear. Never leave a moka pot unattended over high heat.

Note: This calculator follows Bialetti manufacturer specifications. The pressure risk language on this page has been flagged for review per CAL-1 Section 2 before publication.

Frequently Asked Questions

How much coffee do I put in a moka pot?

Fill the basket level to the rim, no tamping, no mounding. The basket capacity is the dose. For a standard 3-cup Bialetti that is 15 to 17 g. The calculator shows the canonical dose for each size based on Bialetti manufacturer specs. Unlike a pour-over or AeroPress, you cannot adjust the dose without swapping the basket.

How much water do I use in a moka pot?

Fill the lower chamber to just below the safety valve. That is the maximum fill line. For a 3-cup Bialetti the canonical fill is 150 mL. You can reduce the fill to roughly 90% for a slightly lighter output, but never exceed the valve level. The safety valve is a pressure-relief device, not a fill indicator: water above it can block the relief and create a pressure risk.

Why is the moka pot yield lower than the water I put in?

The lower chamber does not fully evacuate. Approximately 25% of the water remains as residual water and steam; it never passes through the grounds. The practical rule is yield = water fill multiplied by 0.75. A 3-cup Bialetti with 150 mL of water produces roughly 110 mL of coffee.

Is moka pot coffee the same as espresso?

No. The moka pot operates at 1 to 3 bar of steam pressure; a true espresso machine runs at 9 bar. The extraction chemistry, crema formation, and flavour profile are different. Moka pot output is espresso-strength in concentration (the effective ratio is roughly 1:4 to 1:6) but it is not espresso. It works well as a base for Americanos or milk drinks, but it will not produce the same result as a 9-bar machine.

What grind size should I use for a moka pot?

Medium-fine to fine: finer than a drip basket, not as fine as espresso. Espresso-fine grounds create too much resistance for the moka pot's steam pressure and can cause the safety valve to kick. The reference grind is somewhere between table salt and fine sea salt. If your valve is releasing or the brew takes longer than 8 minutes, go slightly coarser.

Timberline Coffee School

Trent built this calculator. He also runs Timberline Coffee School, where baristas and roasters train through SCA-accredited programs covering espresso, brew method, and sensory skills.

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