Btw the winery is called Tierra di seta. Their email is info@terradiseta.it.
I'm gonna be a spokesmen for them because of how nice they were to me in giving me info and helping me plan my trip to Siena.
Without exaggeration they are extremely nice and helpful. They do tours twice a day. One at 11am and one at 5pm i think. You have to make reservations. It's a 25eu cab ride from Siena and I'll hopefully post how I did it by bus (with a walk on top of that

they have beautiful houses on the property that require a weeks reservation. Pricey but looks gorgeous.
The tour is 20eu per person with discounts for groups. It includes a tour of the winery and tastings of their homemade wine, homemade olive oil, artisan crackers, and (maybe homemade) cheese. They told me to plan for a 1.5-2.5 hour total time.
Based on their website and articles about them, their wine is extremely highly rated even in nonjewish competitions and are just starting to import to America. I can't say anything about their kashrus. All I know is they were very nice in explaining that they were closed for Shabbos (I guess they thought I wasn't frum). From what I understand about the family is that they are Italian born frum Jews...