Let me rephrase that. I thought that cold stablization was only required with the introduction of potassium bicarbonate.
Cold stabilization alone can yield a drop of tartaric crystals when dealing with overly acidic grape wines.
You can also use calcium carbonate, ie chalk, but after its use, the wine should be bulk aged at least 6 months to allow calcium malate, a byproduct of calcium carbonate use, to precipitate from the wine. The wine should then be cold stabilized to ensure tartrate crystals do not precipitate out after bottling.
Then you have you have potassium bicarb & after its use, the wine should be cold stabilized, as up to 30% of the potential acid reduction occurs during cold stabilization.
And finally there is potassium bitartrate (a.k.a. Cream of Tartar) is used as a catalyst to help promote cold stabilization. It also promotes the formation of tartrate crystals.
If you do not have an extra refrigerator available, there is an alternative method of cold stabilization. First treat the wine with potassium sorbate and potassium metabisulfite to prevent further yeast reproduction. Then put the carboy in a plastic garbage can just big enough to leave 2-3 inches of air all around the carboy. Fill that space with ice cubes or crushed ice and sprinkle about ¼ to ½ pound of salt on the ice. Stir the ice a bit with a wooden spoon and then let nature take its course. You may get some ice formation on the insides of the carboy, but it shouldn't grow very thick. It is prudent to mark the wine level on the neck of the carboy before starting. If the wine level rises more than ¼ inch (5 mm), remove the carboy until the inside ice melts and then put it back inside the ice slurry. Add ice and salt as necessary. When the slurry loses its frigidness in a day or two, dump out the water and repeat. You'll have to keep it ice cold for at least two weeks, but this does work. (All info per Jack Keller's website)
Arne.
