Make soap the old way — without guessing the lye.
Saponaria pairs old recipes with the arithmetic they never had: a precise saponification calculator, a free field-guide ebook, and a Pro vault for serious makers — paid in Bitcoin over Lightning.
Saponification calculator
Pick your oils and weights, set a superfat, and get the exact NaOH or KOH and water — with lye-safety guidance built in.
Calculate a batch Free downloadThe Saponaria Almanac
A field guide to historical soap: a short history, the science of saponification, and how to handle lye — including the wood-ash tradition — safely.
Read the ebookFrom the Journal
All entries- Formulators
How to Swap an Oil Without Ruining a Recipe
Out of olive oil? Learn the apothecary way to substitute fats by their properties and recompute the lye so your soap still sets true.
2 min read - Formulators
Sodium Lactate for Harder, Longer-Lasting Bars
A gentle salt of lactic acid that firms cold-process soap, eases unmolding and extends a bar's life. Here are the usage rates, benefits and cautions.
2 min read - Beginners
What Temperature to Mix Lye and Oils
A beginner guide to soaping temperatures: the ranges that suit most recipes, and how warmth shapes trace, gel and the look of your bars.
2 min read
Save recipes, go advanced, pay in sats.
Save unlimited recipes to your account, unlock the advanced calculator (cost-per-bar, fragrance load, water:lye), and open the premium recipe vault. Bitcoin Lightning only — no cards, no forgotten subscriptions.