Bret Devereaux

I often wonder how much the 'LOL, ancient people were dumb and didn't understand anything' reaction because our sources are mostly written by leisured elites instead of artisans. Imagine how our metallurgy would look if you made the average senator describe modern steelworking.

The knowledge to produce Roman concrete was essentially lost for 2,000 years—seems plausible

It wasn't that the knowledge was lost but the trade network was, it became impossible to get the ingredients in any quantity.

I thought we still weren’t able to recreate their version?

That is a myth. The recipe is given in De Architectura, published in 25 AD, and rediscovered in 1414. https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Vitruvius/2*.html#5.1 …

Maybe it isn’t the best example—that there’s a recipe disproves my initial point. Roman concrete was very much intended for the use of the “leisured elites” and at that scale they would have to have some sort of replicated and disseminated instruction. Maybe Damascus steel?

We don't know exactly how wootz steel was made. The artisans probably didn't either. We know it had something to do with tiny amounts of trace elements (fortunate ore), and something to do with the artisans' process.

Er, not quite? Wootz is crucible steel. The method has been experimentally reproduced and is fairly well understood. It's one of those things that wasn't so much 'lost' as 'wasn't made in Europe and so was mysterious to Europeans.'