Company email (January 2016):
"The only ingredients in the majority of our wines are Grapes and Yeast. Sulfur is added during the crushing to control micro-organisms. The exception is our sparkling wines to which we add standard white sugar to start a secondary fermentation.
We use Diatomaceous clay as a fining agent on all of our wines."
[Given the difference in answers, we're assuming a production change between 2012 and 2016]
Company email (October 2012):
"For clarification purposes only, we use casein (milk protein) on our wines."
Sumac Ridge Estate Winery (2015 onwards)
Vegan
This product is listed as vegan friendly.
What the company told us
Correspondence on record, with the date of each entry.