Ph and free sulphite
 

G'day from down under.
I was reading Tom S comment (18/04/05) on Ph and the correlation of the
two digits after the point and the correct free SO2 levels. I have never
heard of this before but that works a treat as a guide. It is always a
bit of a challenge when wine making to get the right levels of SO2 in
your wine so they are protected but still low so as not to upset
delicate pallets. How do you check your SO2 levels Tom S? We are using a
refratrometer which is good, but bloody sensitive.

"Fred Meyering" > wrote in message
...
> G'day from down under.
> I was reading Tom S comment (18/04/05) on Ph and the correlation of the
> two digits after the point and the correct free SO2 levels. I have never
> heard of this before but that works a treat as a guide. It is always a bit
> of a challenge when wine making to get the right levels of SO2 in your
> wine so they are protected but still low so as not to upset delicate
> palates. How do you check your SO2 levels Tom S? We are using a
> refractometer which is good, but bloody sensitive.

??? I've never heard of measuring SO2 with a refractometer. Is that
something new, or are you speaking of a specific ion probe?

I usually do it the old fashioned way (the Ripper method):
Titrate an acidulated sample of wine against 0.02N iodine, using soluble
starch as an indicator. It's quick, cheap and accurate to ~ ±2ppm, but a
little tricky to do on very dark reds because of the difficulty seeing the
endpoint.

Tom S

"Fred Meyering" > wrote in message
...
> G'day from down under.
> I was reading Tom S comment (18/04/05) on Ph and the correlation of the
> two digits after the point and the correct free SO2 levels. I have never
> heard of this before but that works a treat as a guide. It is always a bit
> of a challenge when wine making to get the right levels of SO2 in your
> wine so they are protected but still low so as not to upset delicate
> palates. How do you check your SO2 levels Tom S? We are using a
> refractometer which is good, but bloody sensitive.

??? I've never heard of measuring SO2 with a refractometer. Is that
something new, or are you speaking of a specific ion probe?

I usually do it the old fashioned way (the Ripper method):
Titrate an acidulated sample of wine against 0.02N iodine, using soluble
starch as an indicator. It's quick, cheap and accurate to ~ ±2ppm, but a
little tricky to do on very dark reds because of the difficulty seeing the
endpoint.

Tom S