great question!!

Your goal is to just get them talking about some specific subjects.

Knowing about their sulfite additions will tell you a lot about their winemaking philosophy. Just say something like: I heard sulfites are super heavily used in wine, what's your take on them?

If they start defending sulfites strongly, you have a good answer, but also recognize that sulfites occur naturally in wine and you're probably fine if the winemaker uses them sparingly (it can legit make for much better wine).

When asking about pesticides/herbicides, you can't ask directly or accusatorially, ask compassionately. What is your biggest pest/weed problem...what can you do about that?

Those two things can be extrapolated to tall you a lot about their winemaking pholosphy and grape growing philospophy.