I have not yet determine the AW of my product yet. But i think that the WA is not stable. its value may fluctuate, sometime it's higher or lower than 0.65. Problem now is to bring it to the level below 0.65. i dont know to reduce AW to that level
IMHO, yr first priority is to get some data. Unless you have a reason (experience? literature?) to anticipate the Aw is usually > 0.65 ??
Some Aw comments/suggestions here -
PS - cannot you just dry it ?
You can reduce your product’s a w in several ways. Adding humectants like salt and sugar “binds” the water in the product.
You haven’t reduced the water content, but you have reduced the water activity. You can dry the product in a number
of ways; air drying, vacuum drying, freeze drying, and osmotic dehydration all reduce water activity. You can also lower
water activity by lowering the temperature of the product. In many cases, a minor recipe change can bring water activity
to a safe and shelf-stable level.
(from above attachment)