Stems and sulfur

I had to break down a barrel of '14 PN this week for topping. As usual, I gave the topping kegs a big dose of SO2 – up to 35 ppm free. This is a 100% WC vintage, and I’ve kind of been on the lookout for the stems without finding them noticeable. I was actually pretty happy with the stem influence in this high SO2 lot, but it was much more clearly in evidence than with the other 20 barrels at more normal SO2. Has anyone else found this correlation? Had stems show up after a sulfur add? It might explain how stems “integrate” over time when they stick out in newly bottled (and higher free SO2) wine.

I have not tasted that but also never really looked for it either. I don’t taste my wines often just after so2 is added. I much prefer to taste prior. Young high histamine wine is hard enough for me add free so2 and its to much for my asthma I mostly grew out of.

I do find when a wine is shocked with racking, bottling, filtering, so2 hit, etc. that what ever the most prominent aspect of the wine is shows most. Be it acid, oak, tannin (oak/stem), alcohol, VA, brett, etc. dominates a wine.

With stems in particular I find new oak to be the thing that pushes out the stemy character in the nose. I have had many wines (barrel trials and subsequent finished wines) with too much stems for the oak. Where stems alone or with less new I liked the wine better. In my experience in the war of tannins stems can beat out new oak in the first few years.

Stewart- I’ll add this to the list of fascinating & unforeseen effects of additions, be they SO2 or Tartaric. It often amazes me how wines’ expression is altered by adds.

What is the pH of this wine?

P.S. I’ve got an '06 Kendric Marin PN in my cellar that I’m ready to finally pop – will let you know how goes!

pH is about 3.45.
I pump up the SO2 just because the topping wine will have moved at least a couple extra times before it gets back into barrel, and I want to minimize the chances of having the topping wine cross contaminate the whole lot. Pretty standard, right?

Yes, definitely good practice. Also gas those kegs before filling and top them to the very top.

Are you watching Molecular SO2 on your wines? I feel this is very important and overlooked by many “old school” winemakers.

High pH wine requires higher Free SO2 for a given level of “protection” than low pH wines, which are more microbially stable. Molecular SO2 accounts for this variable SO2 “need”.

Some references suggest a Molecular SO2 of 0.8 as a target for white wines, and 0.5 for reds. In general I target 0.8 for my red topping wine, and you’re right there @ 35 ppm free on your 3.45 pH Pinot. Here’s a Molecular SO2 calculator:
https://www.etslabs.com/resources/publications/molecular-sulfur-dioxide/molecular-so2-calculator.aspx

PM me if you’d like more help. And of course pardon me if you already knew this! :wink: