Permitted Processing Aids

Processing aids are added but transient and do not remain to a significant extent in the finished product. Some processing aids may be allergens, and are therefore labelled as being (potentially) present, since allergies can be triggered by the presence of minuscule amounts of the allergen.

It is important to point out that the information presented here is only an introduction to the topic, and not definitive or to be relied on. Some of it may be incorrect and I would welcome comments pointing this out. The FSANZ website lists the applications that resulted in processing aids being allowed, and these will contain comprehensive information, such as relating to food safety.

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Permitted processing aid Source(s) Purpose Health considerations Usage
Activated carbon Made from charcoal To remove colour (such as pink colour from a white juice) or off aromas Probably harmless, but removed from the wine by subsequent filtration. Used to deal with problem wines and otherwise avoided as it strips flavour
Agar Made from red algae (sea plants) Fining agent (?), i.e. to remove undesirable characteristics Widely used in foods, particularly Asian desserts Probably rarely used
Alginates, calcium and potassium salts Made from brown algae (seaweeds) Used in some riddling agents, which are added to yeast used in bottle fermentation of sparkling wine, making the yeast easier to remove at disgorging Used in other foods, so presumably safe Probably only used in the traditional method of making sparkling wine
Ammonium phosphates Synthetic Simple nutrient (nitrogen source) for yeast growth Not toxic within limits (?), but the limits are placed to prevent excess nitrogen or phosphorous remaining in the wine, which would predispose it toward spoilage Widely used to maintain clean healthy yeast fermentation, in particular to minimise the formation of hydrogen sulphide (rotten egg gas) from nitrogen-deficient yeast. Best practice is to measure the nutrient status (YAN) of the must before nutrient addition. May be considered 'junk food' for yeast, and more natural but more expensive nutrients are also available in the form of yeast extracts
Argon Purified from air Inert gas that protects wine or juice from oxidation Non-toxic Very effective but more expensive than nitrogen
Bentonite A specific clay mineral, mined from the ground When mixed with water forms a high surface area of charged particles, which bind to and remove proteins that could otherwise form hazes. Only used in white or rosé wine as tannins in red wine perform the same role Settles out of the wine so that it is separated out by racking and filtration Almost universally used to prevent formation of unsightly hazes in white wines. Alternatives are being sought as the process is inefficient and involves quality loss.
Calcium carbonate Could be natural or synthetic? Deacidification Will be completely consumed by reaction with wine acids Rarely used as it produces calcium tartrate in the wine which is unstable but hard to remove
Calcium tartrate No idea why you would add this to wine, you normally avoid its formation or strive for its removal.
Carbon dioxide (see also additives) Present in air and produced by yeast during wine fermentation Protection against oxidation Harmless in wine: increasing levels make the wine spritzy or sparkling Winemaking procedures involve the reduction of dissolved carbon dioxide levels in wine, as the wine is saturated at the completion of fermentation. However, it is also used as dry ice or as the gas (often in mixture with nitrogen gas) to provide a protective blanket over wine in tank, preventing it coming into contact with oxygen.
Cellulose Natural fibre from woody plant material Component of some fining agents, with the overall purpose of removing coarse or bitter phenolic compounds and hence improving mouthfeel. Cellulose is also used as a yeast support, aiding fermentation in clarified white juices. Harmless Used as a component of some proprietary fining agents (e.g. blends of casein, cellulose and PVPP), as opposed to simple fining agents (casein or skim milk alone). Sometimes added to highly clarified white juices to prevent premature yeast flocculation.
Chitosan Made from chitin, a component of fungal cell walls Antimicrobial effect to aid in control of unwanted microorganisms such as Brettanomyces, plus general fining and clarification uses Shellfish-derived chitosan has a history of use in food products, and chitosan is not allergenic Principally as a means of controlling Brettanomyces, it is added after fermentation is complete. Various other uses are proposed, including as a fining agent and for use in flotation (separation of juice solids)
Collagen see Isinglass
Copper sulphate Synthetic To remove sulphide off-odours Used only at mg/l levels, while gram quantities (i.e. a thousand-fold higher) are toxic. Commonly used to remove off-odours, which tend to become more obvious under good closures such as screwcaps. Copper is also a catalyst of oxidation, so only the minimum possible amount is used.
Cultures of micro-organisms Typically yeasts and bacteria that have been isolated from successful fermentations To ensure reliable fermentation, whether the primary fermentation carried out by yeast, or the malolactic fermentation carried out by bacteria Harmless With careful management, indigenous yeast may give better results in some wine styles than single cultured strains, but the cultures are widely used for reliability
Cupric citrate See copper sulphate
Diatomaceous earth Powdered form of soft siliceous rock formed from fossilised diatoms Used as a filter aid, i.e. leesy wine or juice is mixed with the earth, then filtered, with the earth forming the filter medium The dry powder is hazardous to breathe, but after addition to the juice or wine it is removed by filtration and should cause no residual hazard Used in larger wineries that can afford the expensive filtration equipment. Recovers good juice from juice lees that would otherwise be discarded. Being replaced by other filtration techniques such as cross-flow filtration.
Dimethylpolysiloxane Synthetic, silicon rubber. Presumably used as an antifoaming agent: needs confirmation
Egg white From hen eggs Fining agent used to remove astringent tannin from red wines; the eggwhite coagulates with tannin so that the complex settles out and can be removed by racking and/or filtration You eat the stuff, unless you are allergic, hence it is labelled -- while the vast majority is removed from the wine, it is hard to guarantee that minuscule amounts will not remain Fairly common fining agent. Different wines respond to different fining agents, and trials are typically done to find the most appropriate one in each case
Enzymes Purified from microorganisms that produce them in higher levels than the grape. Most commonly used are pectinases, but other hydrolysing enzymes may be used, such as to accelerate yeast autolysis Pectinase is naturally present in grapes, but may be at insufficient levels to facilitate rapid settling/natural clarification of juice or wine Harmless Widely used in white wines, but also in reds.
Gelatine From collagen, ie. animal tissue Fining agent used to remove astringent tannin from red or white wines; the gelatine forms complexes that settle out and can be removed by racking and/or filtration Edible Widely used to remove astringency from red wines, and to a lesser extent, whites
Hydrogen peroxide Synthetic Powerful oxidant that can be used to remove sulphur dioxide Toxic, but reacts quickly and completely with sulphur dioxide in wine or juice to form water Only occasionally necessary
Ion exchange resins Synthetic Deacidification The particles are usually held in a column, but in any case are easily filtered from the wine More efficient method of adjusting acidity than through addition of wine acids such as tartaric. Use is restricted to larger wineries.
Isinglass Protein derived from fish Fining agent used to remove undesirable phenolics, and useful for clarification Harmless. The allergen, parvalbumin, found in fish is present at very low levels in isinglass and no detectable allergen remains in the finished wine, with no evidence of the wine being able to cause a reaction in those who are allergic to fish. It is no longer necessary to label wine with 'fish products' when isinglass has been used. Less commonly used than other fining agents
Lysozyme Natural enzyme purified from egg white, a rich source Used to control bacteria, an alternative to sulphur dioxide Harmless unless allergic. Needs to be labelled as egg products due to the potential for allergies, even though lysozyme is a weaker allergen than other egg white proteins. Most likely to be used in making sweet wines and probably more widely used in Europe than Australia.
Milk and milk products Cow's milk. Casein is the active protein ingredient and may be used in a purified form, or skim milk may be used directly Fining agent used to remove undesirable phenolics/coarseness, particularly from white wines. Coagulates on contact with wine or juice, allowing a very brief interaction with phenolics to form complexes that settle out and can be removed by racking and/or filtration Harlmess unless allergenic, hence its use is labelled Widely used and effective fining agent for white wines
Nitrogen From air Inert gas used to protect white juice and especially white wine from oxidation Harmless; air is mostly nitrogen Widely used in white winemaking, often in mixture with carbon dioxide
Oak From oak trees, and may be in the form of barrels for wine storage, planks or chips inserted into tanks Oak-derived compounds give flavour and texture to wine, which are more appropriate to some styles than others Harmless Widely used in better quality red wines and some whites
Oxygen From or as air Important yeast nutrient, added during fermentation. Also useful for removal of reductive character caused by sulphides You die if you don't breathe it in Fairly commonly used to manage fermentation or reduction during ferment or maturation
Perlite A mineral modified from volcanic rock Used as a filter aid; alternative to diatomaceous earth Innocuous; filtration removes it from the wine. Probably quite commonly used in larger wineries
Phytates From plants,such as cereal seeds For removal of metal ions such as iron and copper (needs confirmation) Common in diet ?
Plant proteins permitted as processing aids under clause 3(a) to Standard 1.3.3 Plants Fining agents as alternatives to the potentially allergenic proteins such as egg white, casein or isinglass Derived from edible material Probably not very common? Usage is recent, in response to need to label allergens such as egg white, milk and isinglass
Polyvinyl polypyrrolidone Synthetic (aka PVPP) Fining agent used particularly to remove coloured material or bitterness from white wines Inert, and removed through racking and filtration Expensive but useful in some cases
Potassium carbonate Synthetic Deacidification Reacts with wine acids to produce carbon dioxide, so harmless Rarely needed, and probably less frequently used than the more gentle potassium hydrogen carbonate
Potassium ferrocyanide Synthetic Removal of iron or copper Potentially harmful and should only be used by an expert Rarely used, and avoidance of metal contamination is obviously preferable to treatment
Potassium hydrogen carbonate See potassium carbonate
Potassium hydrogen tartrate Natural product of grapes; it is important that the natural L-isomer is used rather than the synthetic mixture of D- and L-isomers. Finely ground crystals are added to cold white wine to seed the crystallisation of natural potassium hydrogen tartrate from the wine, which could otherwise form slowly in bottle making undesirable though harmless 'wine diamonds' a.k.a. cream of tartar, used in cooking Widely used in the contact process to stabilise white wines before bottling. Red wines are less often treated as they may stabilise naturally during maturation, and deposits in bottle are considered more acceptable.
Silicon dioxide aka silica gel, synthetic Used in combination with gelatine fining to encourage settling of the gelatine-phenolic complexes from the wine Harmless Occasionally used for fining
Thiamin chloride and Thiamin hydrochloride Natural, a B-complex vitamin Thiamin chloride and thiamin hydrochloride may only be added to wine, sparkling wine and fortified wine to facilitate the growth of micro-organisms Required in the diet Thiamin may be depleted from must by sulphur dioxide, and therefore added back when necessary to ensure reliable fementation, e.g. at tirage prior to the second fermentation in sparkling wine