Replacing Potassium Metabisulfite

[Huba Huba]

I don't have a way to measure free sulfite but try to remember to replace my K Meta every 6 months. I recently bought a new LD Carlson 2 oz package, Looking on the internet the consensus seems to be that K Meta should be good for 12-18 months from manufacture. There is no date, "manufacture" or "best by" or even a lot number on the package, or on any of the old packages I still have. I always thought that it was good for up to 6-12 months after opened. As far as I know any package I buy could have been sitting on a shelf for 18 months.
How do you know if it is good?

 

[winemaker81]

I make enough wine that I typically buy an 8 oz bag every 12-18 months, depending on usage. However, I've used K-meta that was 2 years old.

Make up a K-meta sanitizing solution, with 2 to 3 Tbsp K-meta in 1 US gallon / 4 liters water with optionally 1 Tbsp acid. Sniff it VERY gently. If it burns your sinuses, it's plenty good.

I'm paranoid about sorbate, as when sorbate ages out, the risk is a batch of mini-Mount Vesuvius, e.g., refermentation in the bottle. If the K-meta reeks, it's still at least somewhat effective so I'm a lot less concerned.

 

[BarrelMonkey]

I make enough wine that I typically buy an 8 oz bag every 12-18 months, depending on usage. However, I've used K-meta that was 2 years old.

Make up a K-meta sanitizing solution, with 2 to 3 Tbsp K-meta in 1 US gallon / 4 liters water with optionally 1 Tbsp acid. Sniff it VERY gently. If it burns your sinuses, it's plenty good.

Sniff test is good. I would also add that if it's stuck together in big clumps it's also time for a new batch - you want it to be dry and powdery so that it can be accurately measured and dissolves fully before adding to your wine.

 

[Rice_Guy]

As a chem lab person, if the potassium metabisulphite is dry it will have years of shelf life. On chemicals I am concerned about I store them in glass. Meta reacts with metal so a plastic lid or at least a Saran liner should be used.
I make a sanitizer with meta. My test for effectiveness is carefully waft some headspace at my noise. It should burn if free SO2 present. On wines if I don’t test, I assume country wines are zero ppm and reds are about 10ppm.

 

[Huba Huba]

OK, sounds like replacing my K Meta every 6 months should keep me out of trouble. I did not know that I needed to do the same with K sorbate, I will start replacing that every 6 months also.
Do you worry about chems included in kits? I have bought a couple of RJS Dessert wine kits recently on sale/closeout and will not make them for a couple of months. Removed/refrigerated the yeast, should I just discard the Meta/KSorb that came with the kits and use my "fresher" ones.

 

[winemaker81]

OK, sounds like replacing my K Meta every 6 months should keep me out of trouble. I did not know that I needed to do the same with K sorbate, I will start replacing that every 6 months also.
Do you worry about chems included in kits? I have bought a couple of RJS Dessert wine kits recently on sale/closeout and will not make them for a couple of months. Removed/refrigerated the yeast, should I just discard the Meta/KSorb that came with the kits and use my "fresher" ones.

IME you don't need to replace K-meta or sorbate every 6 months.

Vendor docs indicate sorbate, in correct storage conditions, is good for 2+ years. Since mine is in a drawer in a clear plastic bag, I keep mine 12-15 months, which allows for time in the warehouse and on the LHBS' shelf. I have never had a problem doing this.

My habit is to date EVERYTHING when I buy it.