The Club has 6 x 500g packs of Bentonite available for purchase -only $2.50 each from David Grant. Place your order next meeting. Read on for the what, why and how of Bentonite. The winemakers friend, Good for mead also.

Bentonite as a fining agent

Bentonite is, indeed, a fining agent. Fining is the action of removing particles that make a haze in wine by combining them with materials that bind to them and force them out of suspension, leaving the wine clear and bright. It not only improves a wine’s appearance; it also makes sure that it is stable. Stable means that it won’t change appearance, taste, aroma, or chemical composition while in storage.

Bentonite is stirred into the wine to remove proteins and other haze causing particles. It works through absorption. This means that it attaches itself to a particle, and together they are too heavy to stay in suspension, falling to the bottom of the carboy, leaving the wine clear and stable. Bentonite settles out so completely that it does not leave any residual taste or color behind.

What is the advantage of adding it to my wine on the first day?

Midwest suggests that you add bentonite on the first day. The reasons behind it go beyond technology, straight into Wine Making philosophy. When bentonite is added on the first day, it disperses through the wine and most settles to the bottom within a few hours. At the end of 48 hours, however, the bentonite is back in circulation. This is because of the process of gas nucleation that the CO2 in the wine is undergoing.

As the yeast ferments the sugar, it converts it into carbon dioxide (CO2) and alcohol. The bubbles of gas don’t actually appear out of nowhere. They want to come out of suspension on some kind of a point, where a nucleus of gas can form the beginning of a bubble. The bentonite is surrounded by a bubble of gas and floats up to the surface of the wine. When the bubble bursts, the particle of bentonite drops back down to the bottom of the carboy, all the time working to absorb the particles that are clouding the wine. In this way, the bentonite is circulated around the wine continuously for days, doing its job.

When bentonite is added to a wine kit post-fermentation, it does not have the advantage of the CO2 lift that it would get during fermentation. Therefore the winemaker is obligated to stir it through the wine repeatedly, ensuring the thorough dispersal. In addition, because the bentonite will quickly settle out before it can effectively clear the wine, significantly more is needed when used post-fermentation. RJS Craft Winemaking kits typically use 10 or 15 grams of bentonite. Some other companies use up to 80 grams! This is far too much. Not only does this amount cause the formation of a deep, loose sediment bed; it also has the effect of stripping the wine.

Finings are considerably more powerful than most people suspect. With a sufficient dosage of finings it is possible to strip a red wine to the point where it becomes ‘white’. Too much finings can lead to a stripping of color and flavor, making it necessary to formulate much darker and stronger wine kits to compensate. By adding the bentonite on the first day, the formulation can be much closer to the desired finished wine, without extra additions or manipulation. Although it may seem a little odd to be adding clay to your wine, when the finished product is clear and delicious, you’ll be glad that there was a little bentonite to polish it up.

Using Bentonite As A Wine Clarifier

By Ed Kraus

What is Bentonite?
Bentonite is a gray, clay granule that is used in wines as a clarifier. It is unique in that it possess a negative electrostatic charge. (Just a fancy word for static electricity) This attracting charge along with hydrogen bonding, causes suspended particles in the wine to cling to it as it settles to the bottom of the container.

What Are The Advantages Of Using Bentonite?

There are several advantages to using Bentonite. It is very effective in dragging out yeast, tannins and other stubborn protein-based particles that may want to linger after fermentation. The result is a wine with a glassy clear appearance and a color that is radiant. It also helps to reduce the occurrence of certain off-flavors, as well as reduce the wine’s ability to oxidize.

How Is Bentonite Used?
Bentonite is relatively easy to use. You start out by mixing it with water into a slurry. The slurry will have the consistency of a thin, watery cement mix. A dose of the slurry mix is then stirred into the wine. It should also be noted here that the Bentonite should not be added to the wine until the fermentation is complete.

The method we recommended for making the slurry is to use boiling water and to mix it in a blender. Blend it for 1 to 2 minutes until a creamy head is formed. The slurry then needs to set for about an hour so as to allow the Bentonite granules to swell and become saturated. The recommended mix is 3 tablespoons of Bentonite to 1 pint of boiling water. It is then recommended that you add 1 to 2 tablespoons of the slurry mix to each gallon of wine that is to be treated.

Are There Any Tips For Using Bentonite?

There are a couple of thing you can do to make your Bentonite treatment more effective:

First of all, the colder the wine is the stronger the Bentonite’s static charge. At room temperature Bentonite is usually adequately effective, but by chilling the wine down to around 45 degrees the Bentonite’s strength is enhanced considerably.

Secondly, when adding the Bentonite to the wine, it is best to stir it in thoroughly. Don’t agitate the wine, but smoothly blend it in to where you know, without question, that it is evenly dispersed throughout the wine.

Also, stirring the wine several times after the Bentonite has been add, will give the Bentonite more time to attract particles before settling. For example, stir it once every hour or so throughout an evening.