This recipe is not based on a medieval source, there are no separate recipes for medieval stock. Stock was so common, there was no need to write down recipes for that, just as with recipes for baking bread. Often, the stock used in recipes was simply the liquid in which meat was cooked. So here is an educated guess from me, which is no doubt influenced by my knowledge of how stock is being prepared today. Medieval stock can also be made from mutton, as that was often on the medieval menu. A recipe for Modern beef stock.
For 2 litres/4 pints beef stock; preparation 4 hours + straining the stock.
3 pounds shin of beef
1 carrot or parsnip
1 onion with peel
1 bunch of parsley, piece of parsley root
small piece of mace
black pepper, crushed
3 liter (6 pints, ¾ gallon) water
Wash and clean all vegetables, cut them coarsely.
Put the beef in the pan with cold water, bring to the boil. Then skim very carefully before adding the vegables, herbs and spices. Cover the pan with a lid and let the stock simmer for four hours on a very slow fire. The stock does not need be boiling.
Strain the stock, and reduce to two litres, then let it cool quickly. Now you can freeze what you don’t need immediately.
Do not forget to label your frozen stock, in the freezer all stocks look alike.
A (modern) recipe for medieval beef stock