Have you ever thought about the ingredients in wine? Why do they not list the ingredients like most food and beverage products? Why are they not held to the same standards as others in the food and beverage industry? Well, the Reverse Wine Snob will reveal some information that may or may not influence your purchasing, and enjoyment of wine.
I will quote RWS (Jillian Johnson), rather than try to paraphrase in my own words.
Yeast and Yeast Nutrients
There are hundreds of different yeast strains available specifically for fermenting wine. Yeast can impart aroma and flavor, as well as increase mouthfeel. Most yeast strains are non-GMO. Yeast metabolize the sugar into alcohol, but they need other nutrients to keep the fermentation healthy. There are two main choices for yeast nutrition, Diammonium Phosphate (DAP) and autolyzed yeast (amino acids). Yes, the organic answer for yeast nutrition is feeding yeast with pulverized yeast parts. DAP is the manmade option that the yeast gobble up and kick into high gear fast fermentation.
Enzymes are used in many food industries as process aids. In white wine, enzymes are used to help extract more juice from the grape berry and help clarify the juice. In red wine, enzymes are used to extract more color and tannin from grape skins. Pectinases make up the majority of the enzymes used in grape processing.
Tannins naturally occur in wine, coming mostly from the grape berry and oak aging. Through extensive research and development, many different tannin products are available for all winemaking stages. Tannins are purified from the grape skin and seed, oak staves, and other exotic woods (Quebracho, chestnut, cherry, citrus, etc.). Tannins add more structure, help to stabilize color, protect the wine from oxidation and add flavor complexity.
When a wine has an off flavor, too much tannin, bitterness, or oxidized color, a fining agent can be used to correct the issue. Fining agents come is all shapes and sizes, but function by binding with the compounds that are causing the issue and settling out of the wine. There are many choices for protein based fining agents; albumin (egg white), casein (milk), isinglass (fish), patatin (potato), gelatin (porcine), and pea protein. Other fining agents are bentonite (sodium/calcium clay), and Polyvinylpolypyrrolidone (PVPP). Depending on the wine and the issue, a combination of these can be used to fix the problem. Fining agents do not remain in the wine, they are considered a processing aid.
As wines age in the cellar, the wine comes into balance and the texture or mid palate richness develops. Often a wine might be lacking mouthfeel and need help achieving this balance. The tools available are products extracted from yeast cell walls, such as mannoproteins and polysaccharides. Gum Arabic, a product that is commonly found in ice creams, can also be used to soften a wine and bring more mouthfeel.
The above mentioned ingredients are used in very small amounts, typically measured in “parts per million”. Other ingredients not mentioned above are sulfur dioxide, tartaric acid (naturally found in grapes), malolactic bacteria, and other stabilizing agents. Wine is a commercial product and winemakers use these ingredients to make the best wine and a stable product to sell to the customer. If (or when) the TTB requires ingredient labeling for wines, the ingredient list will be a short one compared to many commercial beverages sold today.
Next time you open a bottle of wine, take a look at the ingredients.