Hanna HI 83749-20 - Bentocheck solution, 100ml, for use with the HI-83749-01 Turbidity meter

The prevention of protein haze or deposit in bottled wines is a concern, and often a wine needs to be stabilised before bottling. Fining, or clarifying, is the process of removing substances that contribute to haze by binding them through adsorption.

Bentonite clay is a commonly used fining agent in wine; it is negatively charged and incorporated into the wine as a slurry, or fine powder mixed with water. The negatively charged clay binds to the positively charged protein molecules, and this neutralisation allows the particles to settle out, transforming the beverage to a desired colour and clarity.

This process also makes the wine more stable, meaning the wine’s signature taste, aroma, and appearance won’t change while in storage. However, it is important for a winemaker to know exactly how much bentonite to add - if added in excess, it can actually strip the characteristic colours and flavours.