I'm watching Doomsday Preppers, and a beekeeper claimed that honey was once used as currency—and that it was worth its weight in gold.
I've found a couple ancient examples of honey used as a currency, but no indication as to the worth of that honey.
How would I go about finding the worth of honey and gold by weight in an ancient civilization?
As far as we have information about prices, no, honey was nowhere near being worth its weight in gold.
For a relatively recent example, in 14th century England, a craftsman could buy a gallon of honey with a typical daily wage.
Going back in time, we have the Price Edict of Diocletian, c. 300, with late Roman prices:
Best quality honey: 40 denarii per pint (about 600ml)
Second quality honey: 24 denarii per pint.
These are same as the prices for first and 2nd pressed olive oil. The second quality honey was worth about the same as pork (12 denarii per pound, about 330g).
Essentially, once beekeeping was established, honey had no chance of being close to gold in value. If honey prices rose, people would keep more hives, and the prices would fall. Before beekeeping, when all honey was collected from wild hives, honey could be more expensive, but since beekeeping dates to the 3rd millennium BC or earlier, we don't know earlier prices (and gold might not have been so valuable then, either).
For money on honey prices, see https://www.reddit.com/r/AskHistorians/comments/d5y9vr/short_answers_to_simple_questions_september_18/f0uu7h3/