Wednesday, November 21, 2007

SO2 Quick Test: You Get What You Pay For

We are supposed to bottle tomorrow, Thanksgiving, but we were running blind without an accurate SO2 test. On Monday, I ordered a quick and dirty kit from Vintner's Vault, which arrived yesterday. This morning, I opened the kit, and read the directions. The kit is from Accuvin ( I took samples of wine from the 2006 Merlot Reserve and the 2006 Nebbiolo. This was the first time for me to use such a test -- it's about time, after 4-years of winemaking, and I found it easy to do. Just follow the directions, taking a minute sample of wine, adding it to a vile, then reading a color chart. It seemed that the Merlot came in with a reading of about 16 PPM, about half where I need to be before bottling. Then, I tested the Nebbiolo. As I suspected the Nebbiolo was high, I used the "high range" or "red cap" of the Accuvin test, and the reading suggested 40 PPM (perfect). Just to be sure, I repeated the test, this time using the "Green Cap" for the lower range. The result: 16 PPM (same as the Merlot). The color of the green-cap test vile containing the Nebbiolo was the same color as the green-cap test vile containing the Merlot. So, what is the reading: 40 PPM or 16 PPM? Answer one: neither. Answer two: I don't know. What I do know is not having enough free sulphur when bottling is a recipe for a short shelve life, so, to be on the safe side, I added a 1/2 teaspoon of metabisulfite to the 15-gallons of Merlot Reserve, and 2-teaspoons of metabisulfite (mixed with water) to the barrel of Nebbiolo. Because our biological clocks are geared to bottling on Thanksgiving, momentum drives us to bottling something tomorrow. It will be the Merlot. The Nebbiolo can wait until the weekend. And about the tests, you get what you pay for. When I asked Steve at Vintner's Vault about it, he said he's got a $600 machine that will provide accurate tests. This we need to look into next year.


Reluctant Chemist said...

Accuvin now has a dry version of the Free SO2 test kit. It is stable for over 10 months, and there is no fading of the color prior to expiration. This new kit should make determining the Free SO2 levels easier.

Craig Justice said...

If you work for Accuvine, then please send Bluey a sample, and he'll test it and report his findings to Winemaker's Journal.