There’s recently been a bit of a fuss about some proposed changes to wine labeling in this country. That discussion at the very least raises the issue that most consumers have no idea what is both commonly, and also occasionally, done to their wine during winemaking, and what ends up in the bottle.

Careful. Don’t freak out. This is not an alarmist rant, nor should you turn it into one. Many of these things have been done to wine for centuries. It’s good for you to know however, what is allowed.

According to a report by the International Organisation of Vine and Wine, the following additives, treatments and processes are currently allowed in the United States and my understanding of what each is used for:

ALLOWED DURING FERMENTATION AND IN FINISHED/AGING WINE:

• Malic acid — added to boost acidity of wine.
• Tartaric acid — added to boost acidity of wine.
• Silicon dioxide — used to filter and fine wine.
• Edible gelatin — used to clarify and fine wine (remove sediments).
• Gum arabic — used to clarify wine (remove sediments). Up to .24 grams per liter can be used for treatment.
• Aluminum silicates (bentonite or kaolin) — used to clarify/fine wine.
• Miscellaneous filtration substances (diatomaceous earth, cellulose, etc.) — used to filter wine.
• Polyvinyl-polypyr-rolidone — used to modify color of wine, reduce tannins. Up to 7.19 grams per liter allowed for treatment.
• Activated charcoal — used to filter wine and improve color. Up to 3 grams per liter allowed for treatment.
• Water / H20 — used to reduce alcohol levels, reduce acidity. Up to 35% of total volume. Not allowed in California.
• Concentrated grape must — used to improve body, flavor, color.
• Saccharose — used to increase sugar levels of wine. Not allowed in California.
• Distilled alcohol — used to fortify alcohol levels in wine.
• Oxygen — used to improve texture, tannin development.
• Cellulase — enzyme that assists in the hydrolization of cellulose, a key process in fermentation.
• Protease — enzyme that kills some bacterial agents and makes wine less heat-sensitive and less likely to throw sediment.
• Betaglucanase — enzyme used to reduce sediments.
• Pectolytics – — enzymes that assist in the hydrolization / breakdown of pectin into pectic acid and methanol during fermentation which tends to clarify the wine.
• Yeast — required agent of the fermentation process, converts sugar from grapes into alcohol and lots of tasty flavors.
• Yeast cell walls — bits of yeast cells that absorb anthocyanins (bitter tasting compounds) during red wine production and make the wine smoother.
• Lysosome — I have no idea what this is used for.
• Ascorbic acid –preservative, anti-bacterial agent.

ALLOWED IN FINISHED / AGING WINE ONLY

• Fumaric acid (3 grams per liter, max) — used to boost acidity of wine.
• Lactic acid — used to boost acidity of wine, improve texture.
• Potassium caseinate — used to clarify wine / remove sediment.
• Casein — used to clarify wine / remove sediment.
• Isinglass — a fish product used to clarify wine / remove sediment.
• Milk/lactalbumin — used to clarify wine / remove sediment.
• Ovalbumin (egg whites) — used to clarify wine / remove sediment.
• Ferrous sulfate — used to clarify wine. 0.0222 grams per liter allowed in finished wine.
• Lactic bacteria — used to reduce the acidity of wine.
• Potassium carbonate — used to reduce the acidity of wine down to acid levels of 5 grams per liter only.
• Potassium bicarbonate — used to reduce the acidity of wine.
• Calcium carbonate — used to reduce the acidity of wine down to acid levels of 5 grams per liter only.
• Copper sulfate — used to suppress bacterial growth, eliminate off odors. 6 mg per liter allowed for treatment. .5mg per liter allowed in finished wine.
• Oak chips — used to improve wine flavor.
• Acetaldehyde — inhibits microbial growth and stabilizes the color of wine. Up to 300 parts per million used in treatment. up to .5mg per liter allowed in finished wine.
• Granular cork — used to smooth the texture of wines. Up to 1.2 grams per liter may be used for treatment.
• Catalase — enzyme that counters bacterial agents in wine.
• Glucose oxidase — enzyme used to keep color of white wine stable with age.
• Urease — enzyme used to reduce sediments in wine.
• Thiamine hydrochloride — (aka Vitamin B) food for yeast that is used to help finish fermentation.
• Soy flour — food for yeast to increase and encourage secondary fermentation.
• Ammonium phosphate — assists in fermentation, can help accelerate or “un-stuck” fermentation.
• Diammonium phosphate — assists in fermentation, can help accelerate or “un-stuck” fermentation.
• Sorbic acid — preservative.
• Sulfur dioxide — preservative, anti-bacterial agent.
• Nitrogen — preservative.
• Dimethyl dicarbonate — preservative.
• Carbon dioxide — used to create sparkling wines.
• Potassium metabisulphite — bacterial inhibitor and preservative.
• Potassium sorbate — bacterial inhibitor and preservative used in conjunction with potassium and copper sulfites.
• Ferrocyanide compounds — used in clarifying/fining wines. Only allowed at 1 part per million in finished wine.
• Citric acid — occasionally used to increase acid levels of white wines. Allowed use of .7 grams per liter.
• Potassium bitartrate — stabilizer, prevents sedimentation.
• Fruit concentrate of same grape variety — used to improve color and flavor.

ALLOWED PHYSICAL PROCESSING

• Centrifuging — used for various reasons, but commonly to remove yeast from wine before the completion of fermentation.
• Micro, Nano filtration — removal of sediment from wine.
• Reverse Osmosis — used to reduce alcohol levels.
• Evaporation — allowed during fermentation process only.
• Thermal treatment — aids in color extraction.
• Electrodialysis — a way of preventing tartrate based sedimentation in wines.
• Ion Exchange Resin — a way of preventing tartrate based sedimentation in wines.
• Spinning Cone treatment — used to reduce alcohol levels.
• Thermal gradient processing — used to fine tune alcohol levels.
• Thin film evaporation under reduced pressure — used to fine tune alcohol levels.
• Metal/sulfide reducing matrix sheet — I have no idea what this is used for.

One of the interesting aspects of this report is that it compares what is allowed under the laws of the United States, the European Union, Switzerland, and the OIVs own guidelines. Lots of people like to think that American is wildly lenient and unregulated when it comes to additives and processing in wine, but this report makes it clear that is not the case. Most of this stuff, with a few notable exceptions is perfectly legal in France and Italy as well — two places that are often held up as bastions of “traditional” winemaking practices. Of course, these are just regulations about what is allowed under law, we don’t know what is actually used.

Which brings me to the “so what” of this list. It’s clear that we need a combination of better consumer education and better labeling laws so that people can fully understand what has been used to make their wine, and what is actually in the wine bottle that they pull off the shelf.

Not being a professional winemaker, this list also makes me wonder what is the absolute minimum amount of these additives or materials that needs to be used in winemaking. Is it possible to make a wine with none of the above?

Thanks to Alfonso, who runs the blog On The Wine Trail in Italy, for sending me the link. Now excuse me while I go figure out how to add diammonium phosphate as a descriptor in my tasting notes.