# 🍺 Top-down Brew: Homebrewing Calculators

## What is top-down brewing?

The concept for the beer (top) drives the weights that are needed (bottom). The name is borrowed from sensation/perception research, which views perception as a dynamic interaction between previous learning (top-down) and current sensory data (bottom-up).

## Calculating recipes via targets and percentages

- Updated! Beer Engine: A percentage-driven recipe calculator that runs in web browsers.
- Older versions: Beer engine - concise, Beer engine - FlexStyle, and making your own recipe calculators

## Water tools

- Water volume estimation
- Easy but crude water salt concentrations
- Mash pH from ion concentrations

## Mash processes

- Mash volume estimation: Can I mash it?
- Mash strike water temperature
- Mash step water additions
- Batch sparge water volume
- Diastatic power for mash conversion
- Decoction percentage
- Mash efficiency: Basic tutorial, Advanced
- Grain bill calculations, percentages to weights based on yield with color estimation:
  - Using preset yield values
  - Using coarse-grind, as-is values from malt data
  - Using coarse-grind, dry-basis values from malt data

## Hops and Yeast

- IBU calculations (Tinseth and Rager)
- Yeast pitching rates from the brewing industry and yeast providers

## Wort Gravity Adjustments

- Increasing original gravity with malt extract
- Decreasing original gravity with water
- Parti-gyle blending: Combining two worts of different specific gravities

## Packaging

- Priming with sugar
- Priming with sugar: Volume based upon liquid weight
- Priming with sugar: Pressurized fermentation (spunding valve)
- Priming with sugar: Dry priming - sugar amount per bottle
- Priming with unfermented wort (mit speise)
- Priming with unfermented wort (mit speise) when additional sugar is needed
- Priming with fermenting wort (kraeusening)
- Estimating the number of bottles that are needed
- Keg carbonation pressure calculator

## Measurement and miscellaneous

- Alcohol by volume or weight
- Alcohol after freeze distillation (eisbock, eisbier) or dilution
- Calorie and carbohydrate estimation
- Determine volume from weight
- Determining kettle volume and dipsticks
- Temperature corrections for adjusting specific gravity
- Convert specific gravity to Brix or Plato (and vice versa)
- Refractometer correction after fermentation
- Using bleach as a sanitizing solution

Download all the calculators: topdownbrew.com2026-05-21.zip

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