Water Activity meters, testing, and benchmark recipes
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Tech Help, Tips, Tricks, & Techniques
Thanks Ruth and Clay! The software looks interesting. My fiancee used similar software at a wholesale gelato place she worked, and it was very helpful in recipe development. Probably more than we need right now, but worth knowing about. We've been looking at invert sugar (she is very familiar with it from her work) and I found some Wybauw recipes online that use it without sorbitol. Those have aW values, and give us a starting point.
We'd snap up a Pawkit at $500 in a second. You got quite the deal Ruth! Other than one seller in Indonesia we've not seen anything in that range. A bit over $2k new and the few sales on the auction site have sold closer to $1000. The .02 accuracy is also a bit of an issue. I found the mold free shelf life estimator calculation online and a few percent in water activity can nearly double shelf life. Even if there is variation batch to batch in that range, it adds to the uncertainty.
I spoke with someone at Rotronic before posting this thread and was under the impression that the .008% meter is around $1500 for the sensor chamber (required) and then you need either the hand held reader (also around that price) or the software as you mention Clay. I didn't think to ask for the software price, but reading about it made it sound quite sophisticated (that's fine) but presumeably expensive. Sensible for a large operation but not for the two of us just starting out. If that meter is $1500 outright, plus the few additional expenses for cups and what have you, it seems like a great deal. At $3000 it seems very fair, but not an easy purchase for us.
Our understanding is that U Mass doesn't do the cheap testing, so we need a commercial lab. We'll need that anyhow with final recipes for the health dept. Perhaps we will just start with one of the Wybauw ganache recipes we found and also one of my fiancee's favorites, pay for the tests, and develop from there.
The biggest discovery in this process so far is the very short estimated shelf life of ganache right at that .85 threshold. Eleven days at 72 degrees. Not that we'd store that high. And I know sanitation, technique, packagaing and storage play huge roles in shelf life. When your business model is primarily wholesale, even if only local, a few points in aW really matter. The "three weeks" you usually hear for cream based ganaches seems optimistic, unless the enrobing greatly slows mold growth.
Anyhow, thanks for all the help.
M