Is it appropriate to directly package cookies with insufficient cooling time on the cookie production line

The cooling time of the cookie in the cookie production line is insufficient, and the cookie are packaged directly at high temperatures, which makes them easy to regain moisture and become soft. The principle is that there is still residual heat and moisture inside the freshly baked cookie. When the temperature of the cookie is high, the internal moisture will continue to migrate outward. If the packaging is directly sealed at temperatures greater than 38-40 ℃, water vapor cannot escape from the packaging bag and condenses inside the bag. Cookies will become soft and not crispy after being stored for a period of time,
The shelf life becomes shorter.

Qualified packaging standard: Biscuit center temperature should be reduced to below 30 ℃ before packaging; The relative humidity of the environment is controlled to be ≤ 60%.
1、 The cooling section itself has insufficient production capacity
1. Insufficient cooling conveyor length and short cooling time. The tunnel furnace comes out and enters the packaging machine with a short belt, and the natural air cooling time is not enough.
Suggested cooling time for crispy cookies: 8-12 minutes
Resilience/Thick cookie: 12-18 minutes
improvement plan
Add multi-layer reciprocating cooling conveyor (to increase cooling stroke without occupying workshop floor space)
Widen the cooling conveyor belt, reduce line speed, and extend cooling dwell time
2. Unreasonable arrangement of cooling fan
Only blow on the surface, the bottom of the cookie is blocked by the conveyor belt and cannot be blown; The fan has a low air volume and is stopped due to fan failure; The wind direction is parallel to the belt rather than vertically penetrating the material layer.
improvement plan
1. Double directional blowing (upward blowing and negative pressure suction at the bottom), penetrating cooling
2. The fan is divided into multiple sections: the front section has strong exhaust to take away high-temperature hot air; Slow cooling in the later stage
3. Install adjustable flow nozzles to blow cold air directly onto the cookie dough, not just empty the conveyor belt
3. High cold air temperature and stuffy workshop
The indoor temperature is high in summer, and simply blowing hot air has no cooling effect; There is no fresh air in the cooling zone, only hot air circulation inside the furnace.
Introduce outdoor low-temperature fresh air; Configure a surface cooler for the chiller unit (air-cooled cooling) to reduce the temperature of the cooling air; Overall ventilation and air exchange in the workshop.
2、 Cookie layout and stacking issues, poor heat dissipation
1. After being baked, the cookies are arranged too tightly and tightly, and the heat cannot be dissipated; Stacking and stacking have extremely poor heat dissipation.
Maintain gaps between cookies during cooling and transportation; Try to lay it flat in a single layer instead of stacking it up; Use a comb style dispersing mechanism to separate dense cookies. 

3、 Humidity control in cooling area
The humidity of the cold air is too high, and the surface of the cookies absorbs water and moisture during the cooling process, making them soft even if the temperature meets the standard.
-Cooling air RH>65%: The surface of the biscuit absorbs moisture during cooling;
Control the cooling and dehumidification of fresh air; Turn on the workshop dehumidifier on rainy days; Separate the cooling section and baking area to prevent the backflow of humid and hot air from the furnace into the cooling area.


4、 Contradiction in matching production line speed
The front baking speed is fast, and the packaging machine has a fixed production capacity. In order to avoid stopping the machine, packaging is forced to be done at high temperatures to meet the production demand.
Two processing approaches:
1. Reduce the overall line speed: Reduce the baking, cooling, and packaging speed to provide sufficient cooling time; The disadvantage is a decrease in production
2. Add buffer storage device: Cooling buffer warehouse/material handling buffer tower, as a production capacity reservoir, to ensure that the cooling time is not compressed, and high-speed production can also fully cool down


5、 Process formula assisted improvement
1. Fully dehydrate the back end of the baking process: Do not bake at too low a temperature in the later stage to ensure that the moisture content of the finished product meets the standard (usually 2-3.5% for crispness); Biscuits with high moisture content require higher cooling and are more likely to soften
2. Formula fine-tuning: increase oil appropriately to reduce moisture absorption; Reduce the amount of high hygroscopic syrup used (if allowed by the customer's formula)


6、 Protective measures for packaging process
1. Add temperature detection alarm at the inlet of the packaging machine, and automatically alarm/reject if the temperature is higher than the set temperature
2. Use high barrier moisture-proof film (BOPP composite film) for packaging bags; Do not use thin ordinary PE film
3. If necessary, place food desiccants inside the packaging (depending on product standards and customer requirements)