In the field of biscuit production, “checking” is a phenomenon that which biscuits or crackers have small cracks or hairlines in them and are sometimes almost invisible. Broken biscuits or crackers can be rejected by retailers and a reason for customer complaints that will damage brand reputation. It happens mostly during some period after baking or packaging, when opening a package and/or touching the product with minimal force the biscuits will break. In fact, this phenomenon occurs days after packing, which makes it hard to find out in real-time during producing process.

As the biscuits or crackers bake, the moisture loss that occurs during this period will develop the stress gradients within the biscuits till it reaches equilibrium eventually. This process is what affects the degree of biscuits checking. The following are some variable parameters that affect the checking:

Mixing

The factors in the mixing stage should be balanced. For the recipe, the higher fat levels tend to reduce the probability of checking. Meanwhile, the higher water content tends to increase the probability of checking. Using higher gluten flour may also cause the increase due to the dough will have higher water absorption capacity and stronger toughness. For crackers, the fermentation time too short will cause the dough to become tougher which will increase the probability of checking due to the enhancement of stress within. Moreover, the mixer type,  mixing speed and mixing temperature should maintain consistently to ensure the even distribution of ingredients. Unevenly distributed raw materials might enhance the stress within the dough while sheeting.

Forming

Stunted biscuits are easier tend to checking than those that have a better lift. As more laminations are used during sheeting the lower chance of causing checking. During the sheeting stage, the dough weight difference across the conveyor belt needs to be minimized for a more even bake. In addition, the distribution and number of docker pins will also have an impact on checking. Clever placement of docker pins can help moisture loss more evenly from the raw biscuits. It’s suggested to relax the dough sheet especially before cutting to release the stress within the dough.

Dough relaxing

Baking

The baking process is the process of redistributing the moisture content of the biscuits. The biscuits more prone to checking usually contain more moisture within the center. Besides, high moisture overall contents of biscuits which are under-baked should be avoided. The first area of the oven should have relatively higher humidity to speed up the penetration of heat to the center of the raw biscuits. Furthermore, it is necessary to keep the temperature of the top and bottom of the biscuit in balance.

Post baking

Avoid using active and rapid cooling methods such as cold air machines which will make the higher moisture content at the center of the biscuits escapes causing the center to shrink and the edge to expand. The temperature and humidity of the environment where the cooling conveyor is located need to be well controlled. Excessive temperature and humidity can cause cookies not to cool sufficiently which may cause biscuits to sweat after packing and eventually checking.

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