Spanish/Basque/Asturian Sidra (Spanish Cider)

Is anyone familar with the cider (sidra) produced in the Basque and Asturian regions of Spain?  I am very interested in trying to reproduce it here.

This is what I know- They use an indigenous yeast (maybe wild).  It’s then fermented and aged in very large barrels underground.  So I’m thinking they use a brett and saccharomyces mix fermented in wood (maybe oak) at cool temperatures.  Not sure about the apples used or the acid levels.  They don’t carbonate the cider.  Instead it is poured into a glass from height in order to infuse oxygen.  Just curious if anyone has had this cider or experimented with making something like it.

I don’t think they use oak. I heard they use a different wood, but I might be misremembering. I also remember hearing it has a slightly acetic character. That would be hard to get in pleasantly small doses, so maybe add vinegar to taste after it’s done?

I’ve used some wild yeasts before, harvested from different fruits, and none of them have acted or tasted like Brett, fwiw. The closest commercial yeast in flavor to my peach-harvested wild yeast was WY2565, only the wild yeast flocced a lot better. The wild also had more undesirable fermentation byproducts (mostly higher alcohols) than the commercial one.

When people say “wild yeast” they think of crazy flavors. I’m sure there are some wild yeasts out there that do have crazy flavors, but I haven’t been able to harvest any of them.

Many ciders use the natural yeasts present on the apple (maybe) and on cider pressing equipment.
I actually think the underground fermenters are ceramic or something like that. I remember an article about a cidery in Virginia (iirc) that was using this process, but damn - I can’t remember their name or any details.