Mogul Process

Detailed Explanation

The mogul process is the backbone of modern jelly, marshmallow, fondant, and liquor-filled centre production. At the core of the line is the mogul machine: plates pass over the tray stack and print shapes into the starch bed, the depositor doses 70–80°C confectionery mass into these moulds, and trays are routed to the stove room.

Here, starch is not merely a moulding medium but also a controlled drying environment. Tray starch is typically held at 5–7% moisture content and 35–40°C. On contact with the hot mass, starch reaches an 80°C local surface temperature, then immediately cools through evaporation. This transient heat–mass transfer drives outer-skin development, gelatin or pectin network formation, and shape stabilisation in the jelly.

The conditioning tunnel (stove or buffer room) holds trays for 24–72 hours at 30–40°C / 20–30% RH. At the end, the separation station inverts the trays; product passes through rotary sieves and brushes, and starch re-enters the loop. Closed-circuit starch circulation may reach 5–15 t/h.

Why It Matters

Moisture balance on a mogul line directly determines product quality, shelf life, and line yield. If starch is not kept sufficiently dry (e.g. above 9% moisture), the tray bed becomes tacky, mould printing degrades, and deformed shapes appear; starch sticks to the product and visual quality drops.

Conversely, over-drying the starch (below 3%) produces dust, creating dust-explosion risk inside the mogul machine and over-hardening the jelly surface — a classic case-hardening defect.

If the dew point inside the conditioning tunnel is not controlled, condensation forms on jelly surfaces, leading to sticking, mould growth, and downstream defects in sugar panning. From a regulatory standpoint, HACCP risk analysis treats mogul starch as a microbiological control point; aw must remain below 0.60 with Salmonella and Enterobacter monitoring.

Energy-wise, traditional steam–reheat mogul conditioning is among the highest specific energy users in confectionery plants; a properly designed desiccant-based solution can reduce the annual energy bill by 30–45%.

Practical Example

A Turkish jellybean producer is commissioning a 12 t/day mogul line. Design data:

• Mogul stove-room volume: 720 m³ (12 × 10 × 6 m) • Target environment: 32°C / 25% RH (dew point ≈ 9°C) • Starch circulation: 8 t/h, 0.8 kg water removed per cycle • Total moisture load: 26 kg/h (jelly surface + outdoor air + personnel infiltration)

Selection: NKT ADP2000-9500 series silica gel rotor dehumidifier, ADP6000 model • Process capacity: 6,000 m³/h • Reactivation: 95 kW natural gas burner • Outlet dew point: 5°Cdp (4°C margin below target) • Reheat line integrated with condenser heat recovery

Post-commissioning measurements: • Product shape-retention success: 88% → 98% • Starch moisture average: 5.8% (deviation ±0.4) • Annual waste reduction: 95 t/year × 2,200 USD/t ≈ 209,000 USD • Energy savings: 38% versus the legacy steam–reheat system (210 MWh/year)

Engineering Note

Engineering criteria for mogul-line conditioning design:

• Dew point setpoint logic — use dew point setpoint instead of RH; even if ambient temperature drifts, starch moisture equilibrium remains stable. Practical band: 5–8°Cdp. • Starch re-entry temperature — starch returning from the separation station may sit at 50–55°C; gradual cooling and moisture rebalancing are required before reuse on trays. • Airflow pattern — push-pull configuration (top supply, bottom return) provides laminar flow over the tray bed; turbulence lifts and disperses starch. • Dual-stage filtration — F7 + F9 filters prevent starch dust from reaching the rotor and heaters; otherwise rotor life drops from 10 years to 2. • Explosion-proof design — starch MIE (minimum ignition energy) is ~30 mJ; ATEX Zone 22 rated equipment is recommended. • Cooling capacity — desiccant rotor outlet is warm (45–55°C); a downstream cooling coil is necessary for a 32°C setpoint, and chiller sizing must follow the moisture-load calculation.

For dew point measurement, a chilled mirror dew point meter or a high-accuracy capacitive sensor (±2% RH @ 0–60°C) is recommended.

NKT Application Link

For mogul-line conditioning, NKT typically deploys silica gel rotor units from the ADP2000-9500 and AD1000-3100 series. Both reliably reach low dew point targets (−15 to +5°Cdp), and with modulating reactivation plus a VFD-driven process fan they respond to variable load profiles with 30%+ energy savings.

NKT's design approach in mogul plants includes: 1. Dew-point-based PID control — starch moisture equilibrium independent of RH drift 2. Reheat heat recovery — desiccant rotor reactivation waste heat covers 50–70% of stove-room reheat demand 3. ATEX Zone 22 rated rotor enclosure and heater — starch-dust safety requirement 4. Modbus/BACnet integration — connects to plant SCADA, reports dew point, starch-bed temperature, and energy consumption 5. Dual-stage filtration cassette — fast field-serviceable changeover

Across Turkish and export references, NKT has commissioned this architecture in 50+ jelly/marshmallow/fondant plants; a climate-tracking module provides remote seasonal performance monitoring.