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Troubleshooting Off-Odor in a Viognier

TroubleShooting

Megan M — via Live Chat asks,
Q

I have a kit viognier that has finished fermenting but has a funky smell I can’t identify. (I wish we had a computer-based smell-o-vision!) It’s not vinegar, but it’s persistent. Closest description I have is the smell of grapes when they are green and still on the vine. The taste is fine, and the weird nose goes away in the glass, but I’m hesitant to bottle it. Any ideas? It’s been sitting in its carboy with a solid bung (topped up) for about 8 weeks after the last ferment, and it hasn’t dropped any real sediment since its last racking.

A
Viognier can be a bit of an odd duck. Like Riesling, it can get some of those weird petrol/gas like aromas, and that’s just natural, from the grapes. Like Sauvignon Blanc, it can also get reductive, especially when aged in closed-off situations like you describe. It’s possible it needs a racking or that it even might benefit from a small copper sulfate addition. Always do bench trials here. That’s not the answer if no improvement is noted. You also might want to try fining to help your Viognier drop its turbidity and fall bright, which can often clean up aromas too. If you don’t mind using animal proteins, one that has some nice effects in white wines and can really freshen up aromas is Gelarom from Laffort. I know it’s so hard to do bench trials when you do such small-scale winemaking, but if you’ve got the tools to measure out teeny amounts of liquids like micropipettes (and I wish all winemakers would invest in these, as well as a gram scale that measures to the 0.01), you can do
Response by Alison Crowe.