(translated by u/ralfv)
New to these? Read the introduction first: it explains what is left out on purpose and what the yeast of the time could do.
Source: Küchenmeisterei, the earliest printed German cookbook tradition (late 15th c.), here in two manuscript copies: Solothurn, Zentralbibliothek, Cod. S 490, recipe 133 (c. 1487), and Cologne, Historisches Archiv der Stadt Köln, Best. 7004, 27, recipe 167 (late 15th or 16th c.).
Language: Early New High German (Alemannic and Ripuarian)
Style: Melomel (blackberry) on a wine base
(Solothurn copy)
Item, if you want to make one measure of wine or six from blackberries, take one measure of honey and five measures of blackberries; mix that, twice, well together. After that add six times as much wine. Put it on the fire, let it boil well and skim it, and take it off and strain it through a cloth. Let it ferment (?).
After that put it on the fire again, let it boil, skim it, and then pour it into a clean little cask. Let it ferment.
And when you want to drink of it, try whether it is too strong for you; then to one glassful take two glassfuls of wine and mix it in. Then you have a good drink, which gently helps against the natural heat and keeps it in its natural measure.
Translation: fyndling.de (CC BY-NC-SA 4.0). It was made from the original-language text as transcribed by CoReMA – Cooking Recipes of the Middle Ages, University of Graz, mss. So1 and K1 (CC BY 4.0). That transcription is not reproduced on this page; you can read it next to the manuscript scan via the link below.
Original scan and transcription: fyndling.de/rezepte/so1-133 (Solothurn), fyndling.de/rezepte/k1-167 (Cologne). German-language site; Google Translate works well for reading it.