Corney & Barrow 

To know whether a wine is a vegetarian or vegan, you need to look at how the wine is clarified (or fined) to remove the solid particles that would otherwise make it cloudy. The substances used for this process can be derived from many sources, some of which come from fish and animal, some from dairy products and some from clay or synthetic substances. Certain producers do not fine their wines at all while some choose just to filter.

Strictly speaking, such substances are no longer found in the wine at all after clarification, but the fact that they have had contact with the liquid may be important to some people.

If a wine is fined with the following, it is suitable for vegetarians and vegans:
Bentonite (clay base)
PVPP (polyvinylpolypyrolidone) – a synthetic substance
Use of tangential filter
No fining

If a wine is fined with the following, it is suitable for vegetarians but not vegans:
Casein (milk)
Albumen (eggs) 

If a wine is fined with the following, it is not suitable for vegetarians or vegans:
Gelatine Isinglass (fish swim bladder)
Blood! (not used generally anymore)