The 100g Bentonite from Youngs is used to aid the clearing of cloudy wines it is a naturally occurring clay. It swells up in the water and absorbs proteins in the wine, dragging them down to the bottom which helps with the cleaning. This handy tool is best used at the start of fermentation in order for great tasting wine! Bentonite Features Youngs Bentonite 100grm/ 4031 Absorbs proteins in the wine Best used at the start of fermentation Youngs\' Ref. MPN: 4031Colour: N/ASizes: 100gPM Ref: 450085