How to prevent Shiitake log expansion when sterilized in autoclave ?

How to prevent Shiitake log expansion when sterilized in autoclave ?

1. bag expansion mainly happens in the early stage of sterilization, that is the temperature rising stage. If temperature rises too quickly, the cold air in the bag will expand rapidly due to the heat.  if the clip is sealed too tightly, the  bag expansion will be more serious. Therefore, the temperature rising time should be extended to allow the cold air in bag slowly discharge through the gap of the clips, which can effectively prevent the occurrence of bag expansion.

2. the sterilization pressure is high. During the sterilization process, if the air intake is large and the exhaust volume is small, it will lead to unsaturation. Excessive steam pressure will also cause bag expansion.

3. the sterilization temperature is high. If the sterilization temperature exceeds 108 ℃, it is high-temperature sterilization.

4. if the power and  air are cut off during sterilization process, the sealing strip will shrink, and the temperature and pressure of the shiitake log will drop suddenly, which will also cause bag expansion.

5. the temperature of the cabinet door is high. After opening the cabinet door, the temperature of the shiitake log will drop sharply, and the bag will also shrink sharply. At this time, if the hot air inside the mushroom bag not discharged in time, it will cause the mushroom bag to expand and deform. Since  autoclave has good sealing performance, the temperature and pressure should be kept relatively stable during the sterilization process. If the sterilization temperature exceeds 100 degrees, you can refer to the values ​​in the "Saturated Steam Pressure Temperature and Pressure Comparison Table" as a basis, which can effectively prevent the occurrence of bag expansion.

In short, the main and most direct reason for the formation of bag bulging is that the temperature rises too quickly and the fungus bag is too sealed, causing the air in the bag to expand due to heat and not be discharged in time and quickly.

PS: poking a small hole（no more than 6mm）and pasting breathable stickers(high temperature resitant) on the bag is the most effective way to prevent bag expansion.