Commercial Acid Protease for Wine: Dosage, pH, and Temperature Troubleshooting

Commercial acid protease wine trials are typically considered when a winery wants to improve protein management, clarification behavior, or downstream filtration without relying only on fining adjustments. Acid protease is a protease acid enzyme designed to hydrolyze susceptible proteins and peptides under acidic conditions. In wine, this matters because finished and fermenting wines often sit near pH 3.0-4.0, where neutral proteases may show limited activity. A fungal acid protease or other acid stable protease may help reduce problematic protein fractions, but results depend heavily on grape variety, heat load, phenolic matrix, alcohol, SO2, and contact time. Buyers should treat the enzyme as a process aid requiring validation, not as a universal fix. A good trial compares untreated control, current cellar practice, and multiple enzyme dosages under identical temperature and mixing conditions.

Useful for bench trials on haze risk and filtration resistance • Most relevant where wine pH is naturally acidic • Should be evaluated against sensory and stability targets

The best acid protease enzyme for wine is usually one that maintains useful activity at wine pH and cellar temperature. Many acid proteases show optimal activity around pH 2.5-4.5, but each product can differ, so the TDS should define the recommended pH range. Typical wine processing temperatures of 10-25°C may slow hydrolysis, while warmer trials around 30-45°C can accelerate reactions if the wine style, oxygen control, microbial risk, and sensory profile allow it. Some acid stable protease products tolerate higher short-term temperatures, but heat exposure must be validated carefully because wine aroma and color can be affected. Contact time can range from hours to days depending on dosage and temperature. Troubleshooting should separate enzyme failure from process limitations: low temperature, short contact, poor mixing, high alcohol, or incompatible fining agents can all reduce apparent performance.

Record actual tank temperature, not only room temperature • Avoid assuming laboratory optimum temperature is appropriate for wine • Check enzyme inactivation or removal strategy if required by your process

A reliable acid protease supplier should support both technical validation and purchasing control. Before ordering production quantities, request a current COA for the batch, TDS for use conditions, SDS for safe handling, storage guidance, shelf-life statement, and any applicable food-use or allergen declarations. The COA should list activity, lot number, manufacturing or release date, and relevant microbiological or composition data when available. During trials, QC should measure turbidity, heat stability, filterability, soluble nitrogen or FAN where relevant, pH, alcohol, free and total SO2, and sensory impact after treatment. Evaluate cost-in-use by calculating enzyme cost per hL at the effective dosage, plus any savings in filtration, fining, tank time, or rework. Supplier qualification should also review lead time, packaging sizes, technical support, change notification practice, and consistency across lots.

Keep retained samples of trial lots and enzyme batches • Use the same QC method before and after treatment • Approve suppliers on performance, documentation, and continuity of supply

An acid stable protease is a protease that retains useful activity under acidic conditions, often around the pH found in wine. In practice, this means the enzyme can hydrolyze selected proteins or peptides where neutral proteases may be inefficient. Buyers should still verify performance in the actual wine matrix because alcohol, SO2, phenolics, temperature, and contact time can change the result.

Start with the supplier TDS and create a small trial matrix with an untreated control and at least three dosage levels. Keep pH, temperature, mixing, contact time, and sample volume consistent. Measure turbidity, heat stability, filtration behavior, and sensory impact. Do not scale up from a single beaker result; repeat the best condition in a pilot tank or representative cellar trial.

Acid protease should not be assumed to replace bentonite without validation. It may reduce some protein-related issues, but wine haze stability depends on grape proteins, phenolics, pH, alcohol, and processing history. Many wineries evaluate enzyme treatment as part of a broader stability program. Compare enzyme-only, bentonite-only, and combined approaches to determine the lowest-risk, lowest-cost process.

For B2B purchasing, request a COA for the supplied lot, a TDS with dosage and operating conditions, an SDS, storage and shelf-life guidance, allergen and food-use statements, and traceability information. The COA should identify lot number and activity data. For recurring supply, ask how the supplier manages specification changes, batch variation, lead time, and technical support.

Common causes include low cellar temperature, short contact time, insufficient dosage, poor mixing, enzyme activity outside the wine pH range, high alcohol inhibition, or interference from fining agents. The wine may also contain proteins that are not readily hydrolyzed by that enzyme. Repeat the trial with confirmed enzyme activity, controlled temperature, longer contact time, and a clear analytical endpoint.