Beyond the sulfites, winemakers don’t have to tell you everything that goes into your wine.
But often your bottle is packed and processed with a lengthy list of safe-to-drink preservatives, fining agents and even flavorings. As organic farming and biodynamic winemaking take hold of the industry—and with a few producers beginning to list every ingredient—it’s time to take a look at exactly what could be in your wine.
Protects and preserves the integrity of the wine. Sulfur can stop fermentation, if needed, and kills the nasty microbes and bacteria that can harm a wine’s flavor or aroma.
Like sulfur, potassium sorbate (also used in cheese and yogurt) wards off bad bacteria. In sweet wine, it’s often used to prevent further fermentation once bottled.
Often added to enhance structure and astringency for varietals that are naturally tannin-deficient, or for grapes lacking them due to vintage conditions. The powder is often a mix of grape seeds and skins, oak, chestnuts and nutgall, which are small nut-like swellings on tree branch bark.
Used (where wine laws allow it) to restore water lost to dehydration or to lower sugar/alcohol levels.
Certain enzymes help cull compounds from the skin and help clear out any impure, microscopic crud leftover from fermentation.
When faced with underripe grapes, winemakers may add sugar to still wines to increase alcohol levels. Sugar may also be added before bottling to improve mouthfeel and lower astringency. Many regions allow the practice (known as chaptalization), but in California sugar can’t be added to any still wine. The only time it’s allowed in the Golden State is during the dosage phase of sparkling winemaking—the stage just before it’s corked.
A brand of wine-grape juice concentrate, Mega Purple boosts both color and sugar level—without technically adding pure sugar (hello, California). It’s commonly used in commercial fruit juice. There are similar grape concentrates for white and rosé wines.
Oak chips, staves or powders
These incarnations are far cheaper than barrels and provide for increased surface contact with the wine, which can help with consistency. Winemakers can choose from American or French oak and pick specific flavor profiles, from vanilla and coconut to leather, smoke and spice.
Acid is a critical component in wine that affects microbes, particle stability, color and aging potential. Tartaric acid is prevalent in wine grapes and is the most common addition. Malic and lactic acids are also naturally occurring and often blended with tartaric into low-acid wine. Grapes also contain small amounts of citric acid, which can be added before bottling to “lift” and add brightness to white wines.
Yeast, the key ingredient in converting grape juice to wine, is a one-cell critter that gobbles up sugar and makes alcohol. Yeast also impacts aroma, mouthfeel and flavor.
The Four Main Fining Agents
Suspended particles naturally occur when fermenting grapes and aging wine. These particles cause cloudiness and sediment. Winemakers clear wine by adding agents that glom onto these floaters and absorb them. While many of these agents may alarm, know that these chemical sponges are filtered out before bottling.
Known as isinglass, this pure form of protein can be used to pluck out bitter tannins and binds with haze-inducing particles.
Egg whites and gelatin are especially effective in clarifying red wines. Casein, a milk protein, is used to clarify white and rosé wines.
In addition to absorbing, it helps reduce astringency. Mined in Wyoming, bentonite packs the most sponge power of all the clays. It’s common in toothpaste.
PolyVinylPolyPryrolidone, or PVPP, is a workhorse. It eliminates ugly colors and helps stabilize the wine.
When yeasts get sluggish and winemakers don’t want to feed them sugar to boost fermentation, they add nutrients. These additives are basically vitamin pills for yeast.
When a batch contains too much acid, minerals like calcium carbonate come to the rescue. Think of them as Tums for wine.