Verjuice
Not wine, nor vinegar. Verjuice is a sour fruit juice, sometimes from crabapples or unripe grapes
Literally verjuice means 'green juice'. It is the juice from unripe grapes, unripe apples, sorrel, goose berries, whatever, as long as it is sour. It is a common ingredient in medieval recipes, and even in later recipes up to the seventeenth century. Then it kind of got forgotten, until these days when it is making a slow come back.
The taste of verjuice Platina cites Macrobius' description of the taste of verjuice: Vinegar is sharper than verjuice ("acetum acerbius acore est", edition, II.26). Verjuice will become milder as it gets older, and it will not keep indefinitively. It was used frequently in the Middle Ages. It could happen that in the summer the old stock of verjuice had gone off, or was simply used up. There are several recipes for 'summer verjuice', that were meant to tide things over until the new verjuice from grapes was again available. But this new verjuice was often too sharp in taste. If there was any old verjuice left, both kinds of verjuice were often blended (See the Ménagier de Paris, edition p.260).
Because verjuice was often not available the whole year round, alternatives are mentioned, like vinegar, gooseberry juice, lemon juice or rose water (which amazes me, because that isn't sour at all). In Northwest-Europe verjuice was probably made from apples rather than grapes. So apple vinegar may be an excellent alternative if you can't buy or make verjuice.
Verjuice in summer and in winter
The recipe for summer verjuice was well known. An older version can be found in the Middle Dutch manuscript KA Gent 15.1. In Le Ménagier de Paris from the fourteenth century there is also a recipe for summer verjuice, which uses instead of vinegar and wine white (which means old) verjuice ("Vertjus d'ozeille", edition p.258). This kind of defeats the purpose of making summer verjuice because the old verjuice has run out.
The recipe for winter verjuice can also be found in the Medecynboec from 1593 by Carolus Battus(edition). The salt is not roasted, and the verjuice is boiled to conserve it.
Gheeraert Vorselman has provided us with two recipes for verjuice in his Nyeuwen coock boeck ('New cook book', 1560, edition recipes XVI.22 and XVI.23).
Om groen verjuys te maken tsomers.
Neemt de tweedeel sulckerbladeren ende het derdedeel petercelie ende stoot dese tsamen ende dan doet dat met wat wijns ende azijns door eenen stromijn. Ende oft ghi geenen sulcker gecrigen en cont, neemt daer voor wijngaertcrammen.
Om winterverjuys te maken.
Neemt verschen most van onrijpe druyven, ende doet daer in geroost sout, so matelic dat daer na niet en smake, ende dan doeter in een deel onrijpe mispelen.
To make green verjuice in the summer.
Take two thirds sorrel leaves and one third parsley. Grind these together, and strain them with some wine and vinegar through a sieve. And if you can't get any sorrel, take vine leaves instead.
To make winter verjuice.
Take fresh must from unripe grapes, and add roasted salt, so little of it that it won't be tasted, and add some unripe medlars.
Must - This is fermenting grape juice. When ripe grapes are pressed, the juice will ferment (through natural or added yeast). Must can't be kept in a closed container, the gasses must be able to escape. When the first, hefty yeasting is over the must will ripen into young wine. Must is only available just after the grapes are pressed after the harvest, for a short period.
