Shock steaming is a term used for a short steam treatment which can be compared to a short heat treatment. The object of a shock steaming is to achieve a certain wood temperature as soon as possible and then stop the steam process either to prevent damage or a color change. Kiln-direct's steam controller used a special internal wood temperature sensor to help insure that the shock steaming is terminated after the wood has reached the desired set point. When shock steaming it is essential to only steam sticked bundles, since deadpacked bundles will not allow evenly steaming/heating of all the lumber.
Benefits of shock steaming certain species.
Beech (especially european).
Help prevent later color damage during the drying process and has shown to immediately reduce the initial moisture content thereby both reducing the drying time and equalizing the moisture content.
Oak.
Shock steaming or oak has been mentioned as early as 1920's in some kiln drying literature about a short steam treatment, which could help reduce the drying defects in oak. This is not as well documented, but based on experience from Wooddryer System customers who shock steam oak regulary, we believe that you will see an initial drop in and equalization of the moisture content.
When shock steaming a cubic meter of lumber you will probably use 150-200 kg steam (750-1000 lbs steam per 1000 bf.) through the whole shock steaming process.
Kiln-direct believe shock steaming can help provide better drying result on several species. However, very little researc and experimentation has been done on this. The lack of testing is probably due to the fact that few sawmill has special steam chamber on-site for testing.
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