Updated October 2020 with the list available on https://www.palmbay.com/eco-friendly (some vineyards have their own listings)
Company email (May 2016) re Roscato:
"Thank you for contacting us regarding Roscato Rosso Dolce. Roscato red wines (Roscato Sparkling Sweet Red and Roscato Rosso Dolce) are not vegan due to a component that is used during the fining process that is derived from pork. However, all of our white wines are considered vegan (Roscato Bianco Dolce, Roscato Pinot Grigio, Roscato Prosecco and Roscato Sparkling Moscato)."
Company email (November 2015) re Boissiere:
"Thank you very much for your recent inquiry concerning Boissiere Vermouth’s production process. The producer in Italy has confirmed that they do in fact utilize a gelatin-based fining agent, which is completely filtered out before bottling. This product would not be suitable for vegans.
"The producer is in the process of researching vegan-suitable alternatives for fining that would not impact the overall profile of the vermouth. We would be pleased to update you on this front if and when the current process changes."
Roscato Wines
Vegan
This product is listed as vegan friendly.
What the company told us
Correspondence on record, with the date of each entry.