Most people simply enjoy their wine and give no thought to what has gone into it to produce the delicious final product. But as a wine kit maker, you know there’s more to winemaking than simply crushing grapes and letting them ferment. You add some unexpected things as you make your wine, but even you might be surprised at what those things are actually made of.
In the summer of 2004, Dan Berger wrote an article for SFGate.com, in which he laid out the different additives in commerical wine in all their glory: Sleuthing out what’s in wine/Sturgeon bladder in your bubbly?
Fining Agents: These clear out and carry away substances that either had a purpose in the winemaking process but no longer need to be there, or those that could mar the appearance or taste of the wine. Different types of fining agents – isinglass, bentonite, or even egg yolk – serve different purposes. Yet isinglass is produced from the bladders of sturgeons (a type of fish), and bentonite is a volcanic clay.
Any animal product that might normally cause an allergic reaction is processed so thoroughly that the proteins that would have caused the reaction are completely gone, well before the substance ever gets near the wine.
Flavour Correctors: Grapes contain natural tartaric acid, which helps prevent wine from tasting flat. It can sometimes create crystals, which are removed from the wine and often used to make cream of tartar. If there’s too much acid in the wine, an addition of potassium bitartrate will help reduce the tartness. But if there’s not enough tartness to a wine, sometimes acid is added instead. Another flavour additive is oak, which is often added in the form of chips, which are removed when the wine is finished, leaving the oaky flavour behind.
Preservatives: The most common of these are sulphites, which have always been a natural part of the fermenting process. But some additional metabisulphite is also added, to inhibit mould and bacteria, and to prevent oxidation. The amounts used are considered very safe. An ailment formerly thought to be caused by sulphites – Red Wine Headache – has been shown not to be caused by them after all, but probably by histamines instead.