Bentonite

Volclay KWK Krystal Klear Bentonite is a clay-like mineral with a negative charge that, similar to Sparkolloid, removes positively charged particles. It is most effective when the wine is at a warmer temperature, so we recommend using it for fining in late spring or early summer. It also works better at lower pH levels because proteins have a stronger positive charge in more acidic conditions. 

Generic Low-Level Fining for 5 Gallons:

• Blend 1/2 tsp (about 3g) of bentonite with 1/2 cup of hot water (140 to 200°F) in a blender for 1-2 minutes.
• Let the mixture sit for 60 minutes, then stir it well before adding it to the wine.
• Allow the wine to stand for 10-14 days before racking off.
• This method achieves a fining rate of 0.16g/L.

Generic Mid-Level Fining:

• Follow the same steps as above but use 9 grams of bentonite and 3/4 cup of hot water.
• This method achieves a fining rate of 0.5g/L.

More Scientific Approach:

• You can create a 5% bentonite stock solution and run bench trials to determine the lowest effective concentration for clearing the wine.
• Since fining is non-selective, it removes both undesirable particles like yeast and some desirable phenolic compounds. Therefore, it's best to use the lowest effective concentration.
• To make a 5% solution, dissolve 50 grams of bentonite in 850ml of hot water, mix thoroughly, and top up with water to a final volume of 1L.
• Set up trials with clear jars of equal volume, adding varying amounts of the solution to achieve addition rates between 0.3g/L and 2.0g/L. You’ll need to do some calculations to determine the right amount for your needs.
• Let the trials clear overnight. For more detailed technical information, consult BK653 - Monitoring the Winemaking Process from Grapes to Wine - Techniques & Concepts.

Fining with Wine Kits:

• When using a wine kit made from concentrate, bentonite is typically added on the first day for a few reasons.
  • It serves as a nucleation site for CO2 removal.
  • The CO2 movement helps distribute the bentonite throughout the wine, allowing you to use less and achieve effective fining in a shorter time.