Red wine, coffee, tea, cola, etc are all very acidic liquids with wonderful stain causing tannins. Wool loves acidic dyes, that’s why they dye wool with acidic dyes. In the old days, and still today, they will use lime or lemon juice to suspend and set the dyes in veggie dyed carpets. The catch is we can’t use reducers and bleaches to remediate these dyes because they can pull the natural or background dyes out. After we clean your wool area carpet or in-home wool berber, a stain guard is always suggested to prevent those acidic tannins from dyeing your carpet. Stain guards are not ‘bullet proof’ but they give us a fighting chance of rinsing those tannic acid spills out with little to no damage to the carpet. Remember a nasty wine stain can take a $5000 rug to a $500 rug if it can’t be remeditated.