I've used the Titrets for a little while, however, I take their results with a grain of salt. I used them to determine the free SO2 of a Chardonnay I made and determined that it was 40 mg/l at bottling... the wine was bottled very gently without excessive aeration immediately after testing and after only four months in bottle, I tested the free SO2 of one of the bottles in a proper lab and got a reading of only 10 mg/l. Luckily, it was a small batch so I'll drink up a little quicker than I was planning... no sign of oxidation yet, but a FSO2 level of 10 mg/l is pretty low, so I'm not planning on hanging onto this wine too long.
