Sanitizing cocoa powder and adjusting its pH using a PerMix Vacuum Paddle Mixer/Dryer is a precise and efficient process. Here’s how it works, step by step:
Cocoa powder is loaded into the mixer under atmospheric or vacuum conditions.
Optionally, vacuum loading can be used to avoid contamination and dust.
2. Vacuum Environment Initiated
The chamber is sealed, and vacuum is applied to lower the boiling point of any moisture or added liquids.
Lower pressure enables sanitization at lower temperatures, protecting volatile flavors and preventing degradation.
3. Indirect Heating (Sanitization)
The mixer is equipped with a heating jacket (steam, thermal oil, or hot water).
Heat the cocoa powder to 80–100°C (176–212°F) under vacuum, which is sufficient to kill bacteria, yeast, and mold without damaging quality.
Paddle agitation ensures uniform heat distribution and prevents hot spots or burning.
4. pH Adjustment Process
With the vacuum still active (or re-pressurized with inert gas if needed), inject liquid alkali (e.g., potassium carbonate or sodium carbonate) through liquid spray nozzles above the choppers or into the mix directly.
For Dutch-processed cocoa (alkalized cocoa), this step neutralizes the natural acidity and raises the pH from ~5.0 to ~6.5–8.0, depending on target.
Choppers (if included) help disperse the liquid evenly and break down agglomerates during the reaction.
5. Mixing & Reaction Time
Maintain agitation under controlled temperature and vacuum (or slight pressure if using steam).
Allow sufficient dwell time (20–60 min depending on target pH and temperature) for full pH adjustment and moisture reduction.
6. Drying (Moisture Removal)
Once sanitization and pH modification are complete, continue vacuum drying to remove residual moisture and solvents.
Final moisture content is reduced to ≤4%, ensuring shelf stability.
7. Cooling & Discharge
Optionally use the cooling jacket to bring the cocoa powder to a stable temperature.
Discharge through a fully open port or screw discharge to minimize degradation of particle structure.
✅ Benefits of Using PerMix for This Process
Gentle but thorough mixing avoids compacting the powder.
Uniform pH adjustment with optional choppers and precision liquid dosing.
