The Recipes from Caterina and Francesco’s Letter
Translated by Ramon Garcia Castro

Laundry Bleaching Agent
Dissolve seven and a half kilos of sodium carbonate (also called Solvy Soda) in 200 liters of water. When the sodium carbonate is well dissolved, add by stirring 50 kilos of hypochloride of sodium 28Be at 15% of active chloride. Agitate the liquid well and let it stand until it clarifies. Then put it in a *demijohn. You’ll then have 250 liters of lye water. This lye water is for the cold months.
Dissolve seven and a half kilos of sodium carbonate in 200 liters of water. When the sodium carbonate is dissolved add by stirring 50 kilos of sodium hypochloride 22Be at 10 per cent of active chloride. Agitate and let stand until it clarifies. This is the recipe for the hot months.
If you want lye water with a fragrance, add 50 grams of essence in every 100 liters. You need to add the sodium hypochloride. Let it stand in a cement or a white wood vat; never use an iron one. The sodium carbonate is cheap; you can find it in a drugstore as well as the hypochloride.

*Demijohns are large, wicker-encased bottles used for storage and transport of liquids, often wine or spirits. The Italian word is damigianna.