Industrial Black Garlic Production Process & DeAir Daxwell Heat-Pump Drying Technology

17/12/2025

Foreword: Black Garlic - The "Black Diamond" of Deep Processing Agriculture

Ly Son Garlic and Solo Garlic (Single Clove Garlic) are precious specialties of Vietnam. However, to elevate their value from a few dollars to hundreds of dollars per kilogram by processing them into Black Garlic, manufacturers face an extremely complex biochemical process lasting from 45 to 60 days.

This in-depth technical report will analyze the fermentation mechanism, common mistakes when using manual dryers, and process optimization solutions based on the DeAir Daxwell Heat-Pump Dryer technology platform.

Successfully fermented Ly Son and Solo Black Garlic with jet black color, soft texture, and sweet taste. — Black garlic quality depends 100% on the ability to precisely control Temperature - Humidity over 60 days.

Report Table of Contents

1. Scientific Basis: Why Does Garlic Turn Black?
2. Why Heat-Pump Daxwell Instead of Resistive Heating?
3. Technical Analysis of DeAir Daxwell Dryer
4. The 5-Stage Technology Process (45-60 Days)
5. Real Video & Troubleshooting
6. Frequently Asked Questions (FAQ)

1. Scientific Basis: Why Does Garlic Turn Black?

Unlike standard dehydration which only aims to remove water, black garlic production is an aging process accompanied by enzymatic fermentation. According to studies published on NCBI (National Library of Medicine), there are 3 core biochemical reactions that determine quality:

Maillard Reaction (Browning): The reaction between sugars and amino acids under heat (60°C - 80°C) creates Melanoidin - the characteristic black compound. This reaction only occurs optimally when humidity is maintained at 60 - 80%.
Enzymatic Hydrolysis (Sweetening): Natural enzymes in garlic break down starch into simple sugars (fructose), helping garlic lose its pungency and become sweet and soft.
SAC Increase: Fermentation increases S-allyl-cysteine (SAC) content by 5-10 times compared to fresh garlic; this is the most powerful antioxidant in black garlic.

Technical Note: If humidity is < 50%, the Maillard reaction halts -> Garlic does not turn black. If humidity is > 90%, garlic rots. Therefore, independent humidity control is vital.

2. Why Heat-Pump Daxwell Instead of Resistive Heating?

Old methods (industrial rice cookers, electric resistance ovens) often face two major problems: Massive energy consumption and Hard/Dry garlic (case hardening) due to uncontrolled moisture venting.

DeAir Daxwell Heat-Pump drying technology solves this thoroughly thanks to a Closed Thermodynamic Cycle:

Latent Heat Recovery: Instead of venting hot, humid air outside, the Daxwell machine condenses water vapor to recover heat, reusing it to heat the drying air.
50% Energy Saving: Coefficient of Performance (COP) reaches 3.0 - 4.0 (1kW of electricity generates 3-4kW of heat).
Independent Control: The machine can run in "Heat Preservation & Humidifying" mode or "Drying & Dehumidifying" mode depending on the process stage.

3. Technical Analysis of DeAir Daxwell Dryer

DeAir provides specialized models for the black garlic fermentation process, equipped with intelligent control systems:

Key Models

Model	Max Temp	Application Rating
DX-300S / DX-600S	80°C	Ideal. Wide temperature range covers the entire process from enzyme incubation to drying.
DX-xxxD	60°C	Not suitable for the Maillard stage (requires > 70°C).

🛠️ Customization Service

Each customer has their own scale and fermentation secrets. DeAir possesses R&D capabilities to customize specific machine lines for each project:

Integration of Backup Resistance (Hybrid) for rapid heating when needed.
Adjustment of airflow and drying chamber size according to actual factory area.
Reprogramming PLC control algorithms according to the customer's "Secret Recipe".

4. The 5-Stage Technology Process (45-60 Days)

This is the "heart" of black garlic production technology, automatically programmed on the HMI screen of the Daxwell machine:

Stage 1: Enzyme Activation (Days 1-3)
• Temperature: Gradually increase to 50°C - 60°C.
• Humidity: High (80% - 90%).
• Goal: Keep moist for enzymes to hydrolyze starch into sugar.

Stage 2: Maillard Reaction - Blackening (Days 4-20)
• Temperature: 70°C - 75°C (Not exceeding 80°C to avoid bitterness).
• Humidity: 75% - 85%.
• Goal: Garlic turns black from the outside to the core. According to Molecules journal, this is the most critical stage for forming antioxidant compounds.

Stage 3: Stabilization & Aging (Days 21-35)
• Temperature: Reduce to 60°C - 65°C.
• Humidity: Reduce to 60% - 70%.
• Goal: Reduce sourness, stabilize soft texture.

Stage 4: Drying & Plasticizing (Days 36-45+)
• Temperature: 50°C - 55°C.
• Humidity: Lower to 45% - 50%.
• Goal: Remove surface moisture, dry/crisp skin, soft core.

Stage 5: Cooling (Final Day)
• Run fan mode to bring garlic to room temperature before vacuum packaging.

5. Real Video & Troubleshooting

Video: Black Garlic Production Process Close-up

Troubleshooting Matrix

Phenomenon	Cause	Solution with DeAir Daxwell
Soggy / Wet Garlic	Humidity in the final stage was not lowered enough. Weak circulation fan.	Check %RH setting on HMI. Increase fan speed or clean filters.
Bitter Taste	Stage 2 temperature too high (> 85°C) or duration too long.	Lower set temperature to 70°C - 75°C. Recalibrate temperature sensor.
Hard Shell, Core Not Black	"Case Hardening" due to drying too fast initially.	Increase humidity (incubating mode) in Stages 1 & 2. Do not turn on drying mode immediately.

6. Frequently Asked Questions (FAQ)

1. exactly how long does it take to make black garlic?

It depends on the garlic size. Ly Son garlic (small, multi-clove) usually takes 30-45 days. Solo Garlic (large, single bulb) needs 45-60 days for heat to penetrate deep into the core.

2. How does DeAir Heat-pump dryer save energy compared to resistive drying?

Based on real data, DeAir Heat-pump dryers save about 50-60% of electricity. This is because the machine does not vent heat into the environment but recovers heat from condensed water vapor for reuse.

3. Can I request a custom machine design for my existing drying room?

Absolutely. DeAir has an R&D engineering team ready to survey, calculate, and manufacture machines according to the specific dimensions and technical requirements of each customer.

Turn Fresh Garlic into "Black Gold" with DeAir Technology

Don't let spoiled garlic batches eat into your profits. Contact DeAir now for consulting on technology processes and the specialized, energy-saving Daxwell Heat-pump Dryer series.

DEAIR JOINT STOCK COMPANY
Email: operation@deair.com.vn
Hotline: +84 925 977 579 (Ms. Tam) | +84 914 205 850 (Ms. Hoa)
Website: deair.com.vn