As a general rule we expect clarity in our wine. In order to achieve this, however, winemakers must somehow remove any suspended organic solids present in the fermented juice. These solids can include a number of materials including, but unlikely limited to, grape pieces and dead yeast cells from the fermentation process. One common method method for achieving clarity is fining.
The reason not all wines are suitable for vegans is because animal-derived ingredients can be used as the agents in the fining process. Some commonly used non-vegan fining agents include casein (milk), albumin (eggs), gelatin, isinglass (fish), and chitosan (crustaceans).
How do fining agents work?
Most of the particles floating around in an unfiltered, newly made wine have either positive or negative charges. Some fining agents are chosen to bond with those particles, thus make them neutral in charge. For instance bentonite, a vegan fining agent made from clay, has a negative charge and will thus attract any positively charged particles in the wine. Once the particles bind, and are hence neutral, they will become heavy and eventually settle to the bottom of the vessel.
A second type of fining agent does not have an electrical charge, but instead works like a sponge. These agents absorb the particles, causing them to sink and settle.
A winemaker may use a combination of fining agents.
Why don’t all winemakers use vegan fining agents?
Ultimately choices related to fining are up to the winemaker, and can be influenced by a multitude of factors and combinations of determinants that aren’t inherently related to clarity. For instance activated charcoal is used predominantly to remove undesirable odours (e.g. from oxidisation) from wine. Another particular fining agent may be employed to correct other imperfections like bitterness, to stabilise the wine over time, or to improve a wine’s structure.
Then why not simply make unfined wines?
Many people assume that fining is a process related only to clarification, but often there is more to the story. The leftover sediment might negatively affect the quality of the product over time, so it is necessary to remove it.
Having said that, fining isn’t always essential in the winemaking process and there are good examples of unfined wines on the market. It is possible for some wines to clear on their own by letting the solids precipitate naturally (but this is time-consuming). Some winemakers may also choose to filter wines to remove sediment, sometimes in combination with fining. Alternatively, some winemakers may choose not to fine or filter at all.
People often conflate biodynamically made wines with vegan wines, but strictly speaking no biodynamic wine is vegan. While the wines themselves are often vegan, the farming practices are not. Biodynamic farming involves using animal products in the soils, such as bones. It also involves esoteric pseudoscience like burying crystal-filled horns in the soil in order to improve the quality and taste of produce.
When we mention specific bottles on Vegan Food and Wine we endeavour to discuss only vegan-friendly wines. Be aware, however, that while one vintage may be vegan while another isn’t. That is, the wine made one year by a specific producer may not necessarily be vegan the following year. A good example is this Domaine Bousquet Malbec, a long time favourite, which was vegan a few years ago, and then wasn’t, but now it is again.