SO2 Management- Kit use

[mark500]

I am making some Barolo that I am aging in a carboy and startedusing an Accuvin Free SO2 kit.


11-21-09: Completed 6 gallonfermentation and addition of K-Meta per instructions,yielding an SO2 concentration of ~65ppm.


1-29-10: Racked to a 5 gallon carboy. Checked SO2 with kit. Using the "low concentration" kit test tube, I got a ~28ppm concentration. When I used the "high concentration" kit test tube, I got a ~90ppm concentration.
Not surewhy.So I added a 1/8th teaspoon of K-meta to the 5 gallon carboy.


Plan to check the SO2 level in about 2 months.
Anyone use this kit? Why the difference in results between the kit high and low concentation test tubes?


If the kit is not reliable, then why not add 1/4 tsp K-Meta per 6 gallons every 3 months and forgo the measuring?

 

[ibglowin]

Just an "educated" guess here but the kits are designed to have a said accuracy over a certain range of SO2.

Used outside the range of your sample your going to get an answer, its just not going to be as accurate. Its like making a calibration curve with standards of say 1ppm, 5ppm and 10ppm. and then running an unknown sample and getting an answer of 200ppm.Since your sample was outside the range of your standards it gave you an answer, just not a very accurate answer as quite often things are not linear over the entire range but they can be linear over shorter periods or range.

If you ran your sample again using standards of 50ppm, 100ppm and 200ppm you might get a number quite different from the first but it should be closer to the truth as you calibrated within the range of your sample.