Is there any practical difference between sodium and potassium
metabisulfite?

I've been using the sodium variety because I was given a couple
buckets of it. In my reading I never ever see reference to Na, only
K.

NOW I ask the question -- two months into winemaking season!

Born Boozer Loser

glad heart wrote:

> Is there any practical difference between sodium and potassium
> metabisulfite?
>
> I've been using the sodium variety because I was given a couple
> buckets of it. In my reading I never ever see reference to Na, only
> K.
>
> NOW I ask the question -- two months into winemaking season!

Personally I don't think it makes much difference... the local shops
only have Na-meta in tablet form, the bulk is always K-meta. I've heard
the Na-meta is cheaper, but I think people use the potassium 'cos of the
whole sodium-is-evil mantra that was big a few years back. HTH, but it's
only my pet theory :^)

--
charles

"Once ... in the wilds of Afghanistan, I lost my corkscrew, and we were
forced to live on nothing but food and water for days."
- W.C. Fields

"glad heart" > wrote:

> Is there any practical difference between sodium and potassium
> metabisulfite?

Sodium has received a bad reputation over the past few decades due to it's
(alleged) association with hypertension (high blood pressure). For this
reason, sodium metabisulphite is not permitted to be used by commercial
wineries in the US. I have read that sodium metabisulphite can impart a
bitter flavour to your wine, and for this reason I prefer potassium meta in
my wine. However, I still use the (less expensive) sodium meta for
sanitizing bottles and equipment, since the residual is rinsed or drained
off.

There is also a very small difference in the amount of SO2 (which is what we
really are trying to extract from these salts) per measured weight, but not
enough to be significant.

Glad Heart,

Another consideration, and for me the main one, is that K tartrate will
crystallize out of solution at cold temps, but not Na tartrate. This
allows one to alter the pH and reduce the "mineral/salty" taste of a
wine by cold stabilizing.
I use K-meta. Somebody once gave me a 5 lb jar of Na-meta, and I wound
up giving it to someone else. I wonder how many hands that jar passed
through?

Luck, Mike MTM

"glad heart" > wrote in message
om...
> Is there any practical difference between sodium and potassium
> metabisulfite?
>
> I've been using the sodium variety because I was given a couple
> buckets of it. In my reading I never ever see reference to Na, only
> K.

Either will work about the same in the small amounts required for wine
stability, but there are a couple of factors to consider:

(1) The industry standard is potassium metabisulfite. The excess
potassium, although small, can be chilled out of the wine as bitartrate.
(2) It is very important to get your meta(bisulfite) FRESH! The stuff is
reactive as hell, and degrades rapidly with air exposure to sulfate. It
looks the same, but it's dead as a doornail.

Tom S

Thanks everyone.

Tom, my Na Meta is NOT fresh. I don't know how old it might be.
Working with it, it still seems to have that characteristic harsh
smell. Free SO2 levels seem fine in a couple wines I've tested.
Maybe I'm lucky this time. Thanks for the alert.