Achieving tartrate stability is critical for delivering wines that hold up in bottle and on the shelf. One tool that has become increasingly popular for this purpose is carboxymethyl cellulose (CMC), but not all CMCs perform the same. Understanding how CMC works, and how to properly use it, can help you avoid hazes, filtration issues, and color instability.

How CMC Prevents Crystal Formation

CMC helps prevent potassium bitartrate (KHT) crystals from growing by binding to the crystal surface. It does this through electrostatic attraction between the negatively charged carboxymethyl groups in CMC and the positively charged surface of the KHT crystals. The strength of this interaction depends on the molecular structure of the CMC, meaning that different CMCs vary in their effectiveness.

Protein Stability: A Crucial First Step

Some CMC products, particularly those with longer polymer chains, can interact with proteins in wine and cause hazes. Protein stability must be confirmed before any CMC is added. All fining, blending, acid adjustments, concentrate additions, and clarification steps should be completed beforehand. Wines must also be free of particulate matter.

Special care is needed for wines treated with lysozyme, as it is a protein and can react with certain CMCs to form a haze.

ColdStab Cel: Stability Without Compromise

ColdStab Cel, available from ATPGroup, is a 10% CMC solution that stands apart because of its medium chain length and low viscosity, which reduce its tendency to interact with proteins and color compounds. This makes it ideal for microfiltration compatibility, minimal impact on color, and low risk of protein hazing. For most wines, ColdStab Cel can be safely used as the final addition prior to SO₂ or gas adjustment.

ColdStab Cel is even more effective when used in combination with LGA 20 (20% Acacia gum solution) or LGA 30 (30% Acacia gum solution), two stabilizers also available from ATPGroup that inhibit the formation of tartrate crystals. This synergistic approach improves tartrate stabilization while maintaining wine clarity and filterability.

Bench trials are recommended to ensure the right dosage and product compatibility with your wine. For more information on ColdStab Cel or for help with bench trials, contact your ATPGroup Enology Products Specialist, call (707) 836-6840, or visit www.ATPGroup.com