Geranium/geraniol result in a wine. Dump IT.

[St Allie]

Query moved from another thread.

"The reason you don't add sorbate to wine that has gone through mlf is that if it comes out of dormancy, the mlb(acteria) converts the sorbate into geraniol and gives the unpleasant geranium smells and taste - basically ruining the wine. By keeping sulfite levels up enough, this doesn't normally happen even if there was a bit of sorbate somewhere in there.
I will take this into a new post.

Titled 'Geranium/geraniol result in a wine. Dump IT.

As far as I am aware, there is no fix if this happens.

Also my winebooks say that you can end up with a geranium taint if you add only potassium sorbate without the metabisulphate.. none mention malo lactic fermentation specifically.

Is this because my books are all home fruit winemaking?.. I have no idea.

I think it is a relevant discussion .

Allie

 

[grapeman]

Here is a simplistic mention of it
look down near the bottom or search for sorbate
http://www.bcawa.ca/winemaking/ml.htm

do a search on google for "geraniol formation wine" or even ad malolactic in the search. There are tons of technical articles on it.

 

[surlees]

Everything I've ever read (alot!) says it's the combination of mlf and K-sorbate that creates geraniol. I've never read of lack of K-meta being a cause. And yes, when you get it there's nothing that can be done to correct the geranium smell.

Fred

 

[Manimal]

The connection between SO2 and geraniol is simple... SO2 inhibits malolactic bacteria and so suppresses the formation of geraniol by the metabolism of sorbic acid by the bacteria. So as long as the SO2 levels are sufficient to keep the bacteria in check, no geraniol will be formed. However, SO2 doesn't kill all the bacteria, it just inhibits their activity, so as soon as the free SO2 levels drop low enough, the bacteria become active again and geraniol can form. Bottom line is that you should never use sorbate in a wine that has undergone MLF and you should never use sorbate without SO2. I would also argue that you should never use sorbate in a dry wine that will not be sweetened prior to bottling... there is no need for it.

 

[Wade E]

Manimal has summed it up very nice!