I see 2 problem with wine conditioner/sweetening packs:
1. Shelf life of sorbate.
How old is the package? It's sealed in an opaque package and if stored in good conditions, it should be good for ~2 years. If there is a manufacturing stamp on the package, it's wise to read it. I checked my packets and while there is a manufacturing stamp, there's no "best by" or "use by" date.
2. Amount of sorbate actually in the conditioner.
The sorbate I purchase has a dosage of 1/4 tsp per US gallon, so 1-1/4 tsp in a 5 gallon carboy. [I binned my last sorbate packet last year, as it was probably 3 years old, so I'm going by notes from fruit wine recipes.]
How much sorbate is in the conditioner? Sorbate needs to be limited as in excess quantities it can produce off flavors, but if Fred put 5 packets in 10 gallons? Either our collective understanding of sorbate is off, or there's a lot less sorbate in the conditioner than I'd expect. Or both. In any case, I can't imagine 2-1/2 packages of conditioner in 5 US gallons of wine is not enough.
This has me wondering if the wine is protected if only a partial package is used?
I'm going to contact Global Vintner and ask. The unknowns are a problem for me.
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Fred -- my best guess at this time is that the conditioner was old. You may not have had it long, but it may have sat in a warehouse or on a shelf for too long. This is based on the factors I can think of, although I admit there may be things I didn't consider.
We used 6 oz of a conditioner for 6 gallons of Riesling a few months ago. The corks seem fine when I examined the bottles, but we're going to pull a cork this weekend to check. My concern is doubled here, as we used less than half the package on a 6 month old wine, so there was probably viable yeast.
@Matteo_Lahm,
@Matt_Pruszynski -- you are on the manufacturing side of this question -- do you have any background knowledge regarding the conditioner packs?
