I encountered an H2S problem when I made wine from chardonnay grapes that were sprayed with sulfur. The sulfur residue could be seen on the grapes. Of course the H2S may have been caused by some other reason and the problem was resolved by aeration.
I wonder how a spray program of sulfur and copper could affect winemaking. Does residual amounts of sulfur on grapes contribute to free SO2 and H2S in wine? What effects does residual amounts of copper have on wine? thanks Sarge
What makes you think you saw on the grapes was spray? Tim
The berries had what looked like a milky white stain on them. Unless they used milk for spray ha-ha..
It can contribute to H2S in your wine but most vineyards stop spraying sulphur weeks before harvest for this reason.
In a bad season they may have to spray closer to harvest. Also what if it doesn't rain after the last spray, would some sulfur still be on the grapes at harvest?
It's possible the sulphur levels could be high enough to cause troubles in such a situtation. In such cases it's advisable to watch your nitrogen levels and even be a bit heavy handed with nutrients. If you get your grapes unpressed and whole cluster, gently washing them with clean water can removed the residue. You'll need to let them drip dry before pressing.
The Mancozeb I use can't be applied 63 days before harvest. Yet when I was picking my grapes, I could still see the yellow residue on the bottom of the grapes. It was where the original drop formed and dried. Seemed to have just stayed stuck there. So does the 63 day rule indicate that, although the fungicide still appears to be present, it's actually now inert and harmless? Or does it mean our government bureaucracy may have yet bungled again? I suspect the latter, but have also read that Mancozeb has low toxicity. Hopefully they've got THAT right. Ken
This might explain it. Does kumulus (wp sulfur) also have similar sticker spreader? thanks Sarge
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