Dried fruit and nuts are sometimes consumed together as “trail mix,” but that’s not the only reason to group them together. Both dried fruit and nuts are natural products that usually undergo post-harvest processing before they are sold to customers or consumers. Moisture mistakes for both these product categories are similarly painful–too much water means mold, too little means lost profit, not to mention quality issues.
Moisture content isn’t precise enough
Currently, most growers or buyers use moisture content to determine if tree nuts or dried fruit are too “wet”. This can cause problems. First, the moisture level that causes mold is different for every kind of nut or dried fruit. Second, loss-on-drying moisture isn’t a very precise method for measuring moisture–the answer depends on the method used.
Standardize and simplify with water activity
Water activity is different. It’s a snap to identify bad batches that could mold: any product over 0.7 aw can mold, anything under that value won’t. It doesn’t matter what the product is. Using water activity as a standard can eliminate the guesswork over whose moisture meter is right. Two water activity meters measuring the same sample will give the same reading. And if you really want to know your moisture content, the AquaLab DUO can produce both moisture content and water activity from the same reading.