There are a zillion varieties of oaks. Not sure what a Spanish Oak is. Must be from a different part of Texas than where I am. In my area, there is white oak, red oak, etc. Post oak comes from areas to the west of me. So..... people cook with what is available in their area. I can get hickory, pecan and mesquite also but I pretty much stay with oak because of its abundance and price. I have a 1/4 cord of post oak seasoning right now. Currently using red oak. Spanish oak is likely a wood that would work fine but no one talks about it in the Houston area.