How to make walnuts crack open

Walnuts can be cracked by heating, freezing, tool assisted, soaking, steaming, and other methods. These methods utilize physical principles to alter the structure of walnut shells, making it easier to extract intact kernels.

1. Heating method

Place the walnuts in the oven and bake on medium heat for about 10 minutes. High temperature will cause the air inside the walnut shell to expand and create a pressure difference. After taking it out, wrap it with a towel while it is hot and gently tap it. The thermal expansion and contraction effect can cause the shell to crack along natural gaps. This method can preserve the integrity of the nuts and avoid violent impact that may cause debris to contaminate the flesh.

2. Freezing method

Seal the raw walnuts and place them in the freezer compartment of the refrigerator for 2 hours. The low temperature increases the volume of water crystallization inside the shell. Immediately strike with a hard object after removal, and the microcracks formed by the expansion of ice crystals will expand into obvious cracks. The freezing method is particularly suitable for thin shell varieties, and attention should be paid to controlling the impact force during operation.

3. Tool Assistance

Use a professional walnut clip to align with the depression at the waist of the walnut and apply pressure. The lever principle can concentrate the force point. When there are no specialized tools, you can slowly apply pressure to the walnut by placing it between the door crack or the edge of the drawer. The tool selection should match the size of the walnut, as excessive pressure can cause the kernels to shatter.

4. Soaking Method

Soak walnuts in water for 8 hours to soften the shell fibers, then remove them and let them air dry until partially dry. At this point, the toughness of the shell decreases but it has not completely lost its strength. It can be easily cracked along the growth pattern by tapping lightly with a hammer. Soaking for too long can cause the nuts to absorb water and affect their taste.

5. Steaming method

Steam walnuts in water for 15 minutes to soften the lignin, and steam penetration will weaken the bonding force between the shell layers. Immediately supercool the shell after steaming, causing shrinkage cracks due to temperature differences. The walnut kernels processed by this method are easy to remove intact, but high temperatures may reduce some nutrient content.

When handling walnuts, it is recommended to wear gloves to protect your fingers and choose a flat and stable operating table. The cracked walnut kernels should be sealed and stored away from light to prevent oxidation and deterioration. The daily consumption should be controlled within 20 grams, as excessive intake may cause gastrointestinal discomfort. Special groups such as young children and the elderly are recommended to crush the food to prevent choking risks. Walnut shells can be collected and dried for use as horticultural paving materials or handmade ingredients, achieving resource recycling.