We are starting a small molded and slabbed chocolates business from our home kitchen. Our state requires water activity levels below 0.85, as tested at a certified lab. Those tests run $75 each, and travel cost pushes it up substantially. We can't avoid the tests, and we don't want to, but we do want to avoid wasting ingredients and time on recipes that won't pass.
I've read everything I could find on the internet about this subject. From forums here and elsewhere, to obscure papers found on page nine of a google search. I know Wybauw covers the subject in detail in book 3, but from what I've read, he relies heavily on sorbitol, something we don't want to include in our products.
New meters start a bit over $2000, and for $3000 you get a lot better accuracy. We may well buy one, but it is a considerable expense. I've seen software that estimates water activity from recipes, but that isn't cheap either, and I have no idea if their databases are geared towards confections.
I am really surprised that nobody has compiled a list of water activity readings for classic recipes, say a Greweling piped ganache, or a Shotts caramel. I know technique will lead to varying results (cream heated longer, etc). Still, it would be handy to have a set of baseline recipes and aW numbers.
I suspect we'll end up purchasing one of these units. When we do, we'll share results. Meanwhile, if anybody has any advice for us, we are all ears!
updated by @elephant: 04/09/15 06:22:30AM