I'm working on a property in Napa County which is 41 acres of raw, hilly land with no vineyards, but has a winery use permit and an excavated cave of about 18,000 sf. Winery use permits have value in Napa County, but establishing the value of one on a non-vineyard property is challenging. The existing appraisal (borrower-ordered) estimates the value of the permit at $1,750,000. I've tried one paired sale comparison so far that would suggest a maximum value of $866,000. Does anyone have any other ideas about pinning down the value of a winery use permit? Caves can be useful for wine production due to their cool interiors, but valuing a cave is also a challenge. Any thoughts?