Clarifying

The clarification of wine must (juice) works through positive and negative electrical charges or through absorption in order to drag suspended particles down to the bottom of tanks to settle. Various products are used before filtration, during filtration, or just before bottling. Attention! Too much filtration can strip the wine of its flavour and character.

The following are brief descriptions of the clarifying products that I have seen used:

Bentonite (negative charge) is added to remove large particles. It comes as a powder-clay consisting of calcium and sodium. After being mixed with water, the slurry is added to the wine. The bentonite chemicals react to the protein elements in the wine (mainly dead yeast), bonding to them, making them heavy, and dragging the now large particles down to the bottom of the tank. The riper the grape, the more bentonite is required.

Activated charcoal (neutral charge) absorbs bad odors and browning colours caused by oxidization.

Silicagel/Kieselgel (negative charge) removed bitterness from wine and clears out haze. It is most commonly used in combination with gelatin.

Egg Whites (positive charge) or the technical term for the protein found in egg whites, Albumin, is used to reduce astringency and decrease spoilage. It is often used in red wines as it doesn’t react with the tannins and also keeps the red colour intact. You can quite literally use the whites of eggs separated from the yolk, but powder form is safer as you reduce the risk of bacteria contamination.

Flora Clair (positive charge) is derived from plant proteins. It is also a gelatin replacement and thus when used can make the wine, technically speaking, vegan.

Sulfuric acid is added to reduce the affect of Acetaldehyde in wine. Acetaldehyde is a naturally occurring organic chemical compound and a by-product of yeast fermentation. It produces a butter-like smell and can cause wine spoilage. Adding sulfuric acid to wine can protect against this. It is a preservative, antibacterial and antioxidant. Sulfites are found naturally in fruits (and thus wine). Therefore, even wines proclaimed to be “sulfite-free” do contain the chemical, it’s just not deliberately added. Fun fact: dried fruits contain much higher quantities of sulfites than wine. Unsurprisingly, sulfite-free wines retain this peculiar scent to some degree.