# Fermentcalc

> Calculator-first reference for lacto-fermentation. Salt percentages, brine
> ratios, temperature-adjusted timing and batch scaling for sauerkraut,
> kimchi, pickles, hot sauce and friends. Not a recipe blog; a math tool
> with cited food-safety sources.

## Primary calculators

- [Salt calculator (homepage)](https://fermentcalc.com/) — dry-salt mass for a
  vegetable weight and salt %. Covers Diamond Crystal kosher, Morton kosher,
  fine sea salt and pickling salt with exact g/tsp densities.
- [Brine calculator](https://fermentcalc.com/brine) — salt mass for a water
  volume and brine %. NCHFP convention (salt mass as % of water mass).
- [Temperature & timing](https://fermentcalc.com/temperature) — adjusted
  fermentation days from a 68 °F baseline using Noma-anchored multipliers.
- [Salt percentage reference](https://fermentcalc.com/salt-percentage) — the
  canonical salt levels (1.5%, 1.8%, 2.0%, 2.2%, 2.5%, 3.0%, 3.5%, 5.0%)
  with safety notes and flavour character for each.

## Principles

- Percentages are always expressed by weight (salt mass ÷ vegetable mass or
  salt mass ÷ water mass), never by volume.
- Salt grain is named on every calculation — teaspoons of Diamond Crystal
  weigh almost half as much as teaspoons of fine sea salt, which is a
  common source of ferment failure.
- The 1.5% floor for dry-salt ferments and the 2.5% floor for submerged
  brine ferments are enforced as safety verdicts, not hidden as warnings.
- Temperature multipliers follow the Noma Guide (pp. 53–57). A 10 °F rise
  from 68 °F roughly halves fermentation time; a 10 °F drop doubles it.

## Sources

- NCHFP (National Center for Home Food Preservation, nchfp.uga.edu).
- FDA food-safety guidance, specifically the pH 4.6 threshold.
- USDA Complete Guide to Home Canning, 2015 revision.
- Sandor Katz, *Wild Fermentation* and *The Art of Fermentation*.
- René Redzepi & David Zilber, *The Noma Guide to Fermentation*, Artisan
  Books, 2018.
- Linda Ziedrich, *The Joy of Pickling*, Harvard Common Press.
- Korean Food Foundation (baechu kimchi standards).

## What this site does not do

- No user accounts, saved ferments, comments or community features.
- No newsletter, email capture or affiliate links.
- No recipes with blog-style life stories; just the math and the citations.
- No coverage of beer, wine, cider, kombucha brewing volumes or dairy
  fermentation beyond short yogurt references.

## Contact

Data corrections: hello@fermentcalc.com.