Potassium polyaspartate
KPA, the potassium salt of polyaspartic acid
A newer tartrate stabiliser that also works in red wine.
Typical dose
Per the product sheet, at bottling.
When to add it
At bottling, reds and whites alike.
In practice
Blocks tartrate crystal growth like CMC but without forming a haze in red wine, so it covers the case CMC cannot. It is recent and less familiar than the older options, and, like them, it stabilises tartrate only and not protein.
Linked faults are the ones this addition either treats or, used wrongly, causes. The fault page says which, and whether it can be undone.
Others in tartrate and colloidal stabilisers
Metatartaric acid
A cheap, temporary block on tartrate crystallisation.
Carboxymethylcellulose
A durable tartrate stabiliser for whites and sparkling.
Mannoproteins
Yeast-derived colloids that steady tartrate and protein and add texture.
Bitartrate seeding
Seeds cold stabilisation so tartrate drops faster and more completely.