Why bentonite in wine

Bentonite is a good general purpose fining agent used by home and commercial winemakers which is easy to prepare and does not adversely affect your wine flavor. It is especially effective in correcting protein instability, and also preventing cloudiness.

It does not remove tannins so nothing else has to be used in conjunction with it. Krystal Klear KWK Bentonite is a special formulation of bentonite which disperses much more quickly and provides a higher ratio of positive to negative sites for protein absorption.

The average dry particle size is between 20 and 70 mesh. Calcium bentonite requires more stirring to disperse and has a lower swelling and exchange capacity, but shows rapid and compact lees formation. Another positive aspect is minimal aroma removal and unlike sodium, bentonite does not release sodium ions into juice or wine. Two very interesting fining alternatives to bentonite are worth a mention. Proctase, a protease originally developed for human use, is one of these.

This study also showed that while thaumatin fractions were not significantly reduced, heat stability of said wine was significantly improved. While the inline bentonite treatment of wine is obviously not a substitute for bentonite, it shows promise in industrial scale setups. One study showed that by performing bentonite inline dosing, in conjunction with the simultaneous centrifugal removal of yeast lees following alcoholic fermentation, a reduction in wine loss of up to Jaekels, N.

Influence of bentonite on fining on protein composition in wine. Food Science and Technology 75, — Parish, K. Pre-fermentation fining effects on the aroma chemistry of Marlborough Sauvignon blanc press fractions. Food Chemistry , — Salazar, F. Comparative study of sodium bentonite and sodium-activated bentonite fining during white wine fermentation: Its effect on protein content, protein stability, lees volume and volatile compounds. European Food Research and Technology , — Weiss, K.

Effect of bentonite treatment of grape juice on yeast fermentation. American Journal of Enology and Viticulture 53, 28 — Muhlack, R. Bentonite is principally used to remove proteins from white wine and juice, as it is a negatively charged clay colloid and reacts with positively charged proteins, precipitating them from the wine. Use of bentonite in red wines should be limited because of its ability to reduce colour by adsorption of anthocyanins.

More information about protein stability and bentonite fining can be found in the following articles:. Because the positive charge on proteins is stronger at lower pH values, the effectiveness of bentonite is greater in wines with lower pH values.

If it is intended to adjust the pH and titratable acidity of the wine, then this should be carried out prior to bentonite fining, since stability might be different under the new pH conditions. Carbon can be used to remove off-flavours and odours from wine, to decrease browning or pinking in white wines and to remove colour from red wines. Carbon works well in combination with PVPP in both tasks. The compounds to be removed are physically adsorbed to the large surface area of the carbon particles.

The adsorption rate on the carbon surface is typically very fast. Carbon is regarded as a severe and relatively non-specific fining agent and therefore should be used with care. Special care should be taken to avoid exposure to carbon: use eye protection in combination with breathing protection. PVPP is a synthetic polymer used to reduce the level of phenolic compounds associated with browning and astringency in white wine. It can also be used to remove pink colour and pinking precursor compounds in white wines.

PVPP is practically insoluble in wine and absorbs the low molecular weight phenolics, especially anthocyanins and catechins. PVPP is a gentle fining agent which preserves wine aroma, unlike some other fining agents.

When used for colour reduction in white wines, combining with carbon is more effective in many cases, as it helps with clarification of the carbon particles.

PVPP is not commonly used in red wines, however, it can reduce bitterness and brighten the colour. In many cases PVPP can also reduce certain off-flavours and bitterness. Australia was the first country to adopt allergen labelling for foods in December A new clause was included under Standard 1.

The Food Standards Code was amended on 28 May exempting isinglass fish for labelling in wine and beer. For further information, please contact the AWRI helpdesk via e-mail at helpdesk awri.

To obtain copies of any of these papers, please order online via the John Fornachon Memorial Library click here or contact the library directly with your query. Remember Me. However, in this case, we are not trying to thicken the wine. The bentonite is impure clay created by weathered volcanic ash. The material is very absorbent and it binds and bonds onto any floating particulates which cause haziness or cloudiness in wine.

Once it binds to these particles, it will eventually fall out of the wine helping improve its overall clarity. There are two types of bentonite used for fining wine; sodium and calcium. They both contain different minerals, which will probably be listed on the package. The purpose of adding any fining agent is to have it bind on these clouding proteins and eventually precipitate out of the wine to the base of your fermentation container.

They are easily removed by racking the wine and syphoning the wine from the surface ever so carefully so as to leave the solids behind. If you utilize sodium bentonite, you will mix it with water and gradually add it to the wine, but once it is mixed into a solution, the sodium in the form of salts are left behind.

As for calcium bentonite, it leaves behind calcium. This is preferred to salt, however, you have to be careful how much you add as you could later be dealing with tartrate instabilities other solids which precipitate out of wine as salts , but most are harmless.