system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are old recipes so vague?

I was reading an article a little bit ago and it gave an old Medieval recipe. But the recipe was super vague. No measurements at all. How did people use them?
gpt
Recipes were vague for 3 reasons.

1. No standard measurements existed.
2. Ingredients were of widely variable quality and availability.
3. The people making them were expected to know how to cook.

Modern recipes are mostly aimed at people who don't really know cooking that well, and are made simple enough that if you can read and follow directions you won't fuck it up. This is made possible by having a widespread standard of measurements and ingredients of near identical quality being available anywhere.