Batch Brew Scaler

A 15 g / 250 g V60 is one serving. A party is not ‘a bit more in the Chemex’. Scale factor is how many of those cups you want, treating the original water as one cup. Grind size and bloom still matter; you cannot scale a 15 g bed to 120 g and pour the same way without a bigger brewer.

Inputs

Units

Results

New dose: 120.0g
New water: 2,000.0g
Scale factor: 8.00

Recommended gear

Chemex
The obvious home batch vessel. Check that newWaterG actually fits the model you own (6-cup vs 8-cup).
Typical range: $40–$60
0.1 g coffee scale
120 g of coffee is still a weighed dose. A scoop at party scale is how the brew ratio dies.
Typical range: $20–$80
Gooseneck kettle
You may need two kettle fills. Temperature drop between fills is a thermal-loss problem; keep water hot.
Typical range: $40–$150

Calculation method

The original recipe is one cup. Scale equals target cups. New dose and new water are the originals multiplied by that scale. 15 g / 250 g × 8 is 120 g / 2000 g, still 1:16.7. Bloom the larger bed with about 2–3× the new dose, not the old 30 g.

Exact formula

scale = targetCups (original recipe is one cup). newDoseG = originalDoseG × scale. newWaterG = originalWaterG × scale. Limits: Contact time, bed depth and heat capacity omitted; ratio is preserved, extraction is not automatically.

Espresso is not a batch V60

Do not scale 18 g / 36 g shots by 8 and expect a portafilter to cope. Pull eight shots or use a filter recipe.

Frequently asked questions

My original wasn’t one cup.

Then targetCups is ‘how many times that recipe’, not literal mugs. A 500 g Chemex recipe scaled by 2 is two of those, not two 150 ml cups.

Finer or coarser for batch?

Deeper beds often want a slightly coarser grind size so you do not stall. This scaler does not output clicks.

Hold time?

Hot plates cook coffee. Brew close to service or use a thermal carafe. Cost-per-cup still applies to the dumped leftovers.

Disclaimer — no professional advice, no liability

Scaling mass does not scale pour structure. A 2 L batch needs a different grind and pulse plan than a 250 g V60. Taste the first scaled pot before you serve twelve people.

These calculators, pages and any related content are provided “as is” and “as available”, solely for general educational and informational purposes. They are simplified mathematical estimates, not a cupping score, a water lab report or a roasting profile, and they do not constitute professional barista, roasting, food-safety or medical advice.

Results can be wrong, incomplete or inapplicable to your grinder, brewer, beans, water or use case. You must independently verify every figure, assume all risk, and confirm on a test brew before you scale a recipe, descale a machine or change caffeine habits. Hot water, steam and espresso equipment can scald; caffeine calculators are not a substitute for medical care.

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Batch Brew Scaler

Inputs

Results

Recommended gear

Calculation method

Exact formula

Espresso is not a batch V60

Frequently asked questions

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