Hi guys. I recently upped the residual sugar in my 2006 Chambourcin to
0.4% by adding a little table sugar. Prior to adding the sugar, I
dosed the wine with a little potassium sorbate (as if I were making an
off-dry white wine) to prevent refermentation in the bottle. I
accidentally stumbled across an article this afternoon on Winemaker
Magazine's web site that warns addition of pot sorbate to a dry red
that has undergone ML will create geranium off aromas. I'm pretty sure
my Chambourcin has gone through ML since I used an ML culture during
fermentation last year.

In short, is there anything I can do to prevent this from happening or
is my wine doomed? Has anyone in the group experienced this problem as
a result of adding pot sorbate to a dry wine?? If so, will the
geranium aromas ruin the wine or just make it a little funky???

Thanks,
Charles Erwin

It is only when MLB metabolize the sorbate that you get the
geranium problem. Raising sulfite levels above 0.83 ppm
molecular kills the MLB and prevents the problem. Get some
sulfite in there right away !! HTH

Frederick


"Charles E" wrote in message
...
Hi guys. I recently upped the residual sugar in my 2006 Chambourcin to
0.4% by adding a little table sugar. Prior to adding the sugar, I
dosed the wine with a little potassium sorbate (as if I were making an
off-dry white wine) to prevent refermentation in the bottle. I
accidentally stumbled across an article this afternoon on Winemaker
Magazine's web site that warns addition of pot sorbate to a dry red
that has undergone ML will create geranium off aromas. I'm pretty sure
my Chambourcin has gone through ML since I used an ML culture during
fermentation last year.

In short, is there anything I can do to prevent this from happening or
is my wine doomed? Has anyone in the group experienced this problem as
a result of adding pot sorbate to a dry wine?? If so, will the
geranium aromas ruin the wine or just make it a little funky???

Thanks,
Charles Erwin

"frederick ploegman" wrote in message
...
It is only when MLB metabolize the sorbate that you get the
geranium problem. Raising sulfite levels above 0.83 ppm
molecular kills the MLB and prevents the problem. Get some
sulfite in there right away !! HTH

Frederick

That's 0.83ppm molecular SO2.

On Jan 8, 8:49*pm, "frederick ploegman" wrote:
"frederick ploegman" wrote in message

...

It is only when MLB metabolize the sorbate that you get the
geranium problem. *Raising sulfite levels above 0.83 ppm
molecular kills the MLB and prevents the problem. *Get some
sulfite in there right away !! *HTH

* * * *Frederick

That's 0.83ppm molecular SO2.

Charles, I agree with Frederick that you've got to add sulphur dioxide
(SO2) to your wine in order to prevent malo-lactic bacteria from
metabolising your potassium sorbate.

With red wine, the typical molecular S02 level is .5ppm, which is
slightly lower than the .8ppm benchmark used in white wines. This
difference is due to the anti-oxidant and anti-microbial effects that
tannin imparts on red.

In any case, molecular S02 is a function of the wine's pH and the
amount of free S02 in solution. Here are a few examples:

if your wine has a pH of 3.5, you'll need roughly 23 ppm free S02 to
establish .05ppm molecular S02.
if your wine has a pH of 3.7, you'll need roughly 40 ppm free S02 ""
if your wine has a pH of 3.9, you'll need roughly 60 ppm free S02 ""

You can calculate this more precisely with any one of the many 'wine
addition calculators' that can be found using google. Here's one for
reference http://www.fermsoft.com/sulphite.html

Note also that adding 50ppm of free S02 doesn't mean you'll end up
with 50ppm free S02 in your wine. Because free S02 immediately binds
to agents in the wine and thereby decreases, it's a good idea to be
able to test free S02 for greater accuracy and to ensure you use the
right amount.

Best regards,
Darin

Whew! I think I'm going to be ok based on what you guys are telling
me. The pH of my wine is 3.5 and I had the free SO2 tested by a lab
about 6 months ago to be 80-90ppm. I know that's actually a little too
high (my mistake) but it's probably working to my advantage in this
case. I've only racked once since then and I plan to bottle next week.
I'm not sure how much SO2 will be bound by a gentle racking & bottling
but I'm guessing it will not drop the free SO2 below the 40ppm
required for .8ppm molecular @ ph=3.5.

BTW, does the SO2 actually kill the ML bacteria or just make it
incapable of metabolizing the pot sorbate?

For future reference, is bottle refermentation even an issue when
you're only talking about a residual sugar adjustment from 0.2% to
0.5% final RS? If it is an issue, what technique do you guys recommend
to prevent refermentation?

Thanks,
Charles


On Wed, 9 Jan 2008 13:38:21 -0800 (PST), Darin
wrote:

On Jan 8, 8:49*pm, "frederick ploegman" wrote:
"frederick ploegman" wrote in message

...

It is only when MLB metabolize the sorbate that you get the
geranium problem. *Raising sulfite levels above 0.83 ppm
molecular kills the MLB and prevents the problem. *Get some
sulfite in there right away !! *HTH

* * * *Frederick

That's 0.83ppm molecular SO2.

Charles, I agree with Frederick that you've got to add sulphur dioxide
(SO2) to your wine in order to prevent malo-lactic bacteria from
metabolising your potassium sorbate.

With red wine, the typical molecular S02 level is .5ppm, which is
slightly lower than the .8ppm benchmark used in white wines. This
difference is due to the anti-oxidant and anti-microbial effects that
tannin imparts on red.

In any case, molecular S02 is a function of the wine's pH and the
amount of free S02 in solution. Here are a few examples:

if your wine has a pH of 3.5, you'll need roughly 23 ppm free S02 to
establish .05ppm molecular S02.
if your wine has a pH of 3.7, you'll need roughly 40 ppm free S02 ""
if your wine has a pH of 3.9, you'll need roughly 60 ppm free S02 ""

You can calculate this more precisely with any one of the many 'wine
addition calculators' that can be found using google. Here's one for
reference http://www.fermsoft.com/sulphite.html

Note also that adding 50ppm of free S02 doesn't mean you'll end up
with 50ppm free S02 in your wine. Because free S02 immediately binds
to agents in the wine and thereby decreases, it's a good idea to be
able to test free S02 for greater accuracy and to ensure you use the
right amount.

Best regards,
Darin

On Jan 9, 8:41*pm, Charles E wrote:
Whew! I think I'm going to be ok based on what you guys are telling
me. The pH of my wine is 3.5 and I had the free SO2 *tested by a lab
about 6 months ago to be 80-90ppm. I know that's actually a little too
high (my mistake) but it's probably working to my advantage in this
case. I've only racked once since then and I plan to bottle next week.
I'm not sure how much SO2 will be bound by a gentle racking & bottling
but I'm guessing it will not drop the free SO2 below the 40ppm
required for .8ppm molecular @ ph=3.5.

BTW, does the SO2 actually kill the ML bacteria or just make it
incapable of metabolizing the pot sorbate?

I believe the latter.


For future reference, is bottle refermentation even an issue when
you're only talking about a residual sugar adjustment from 0.2% to
0.5% final RS? If it is an issue, what technique do you guys recommend
to prevent refermentation?

It is an issue. The wine can sit still for a while and then just
decide to take of again. Often the aeration at bottling is what gets
the yeast going again - Murphy's law.

For techniques, you can:
- use sorbate, if you didn't do ML and don't mind the taster/smell
- add lysozyme but on reds you'll likely get some deposit because
it'll interact with tannins
- sterile filter
- increase the alcohol content or lower the pH if those options are
okay for the wine
- bottle, store in cool environment and hope for the best

Pp


Thanks,
Charles

Sterile filter sounds like the best option to me. Does that strip the
wine of any character?



On Thu, 10 Jan 2008 11:03:47 -0800 (PST), pp
wrote:

On Jan 9, 8:41*pm, Charles E wrote:
Whew! I think I'm going to be ok based on what you guys are telling
me. The pH of my wine is 3.5 and I had the free SO2 *tested by a lab
about 6 months ago to be 80-90ppm. I know that's actually a little too
high (my mistake) but it's probably working to my advantage in this
case. I've only racked once since then and I plan to bottle next week.
I'm not sure how much SO2 will be bound by a gentle racking & bottling
but I'm guessing it will not drop the free SO2 below the 40ppm
required for .8ppm molecular @ ph=3.5.

BTW, does the SO2 actually kill the ML bacteria or just make it
incapable of metabolizing the pot sorbate?

I believe the latter.


For future reference, is bottle refermentation even an issue when
you're only talking about a residual sugar adjustment from 0.2% to
0.5% final RS? If it is an issue, what technique do you guys recommend
to prevent refermentation?

It is an issue. The wine can sit still for a while and then just
decide to take of again. Often the aeration at bottling is what gets
the yeast going again - Murphy's law.

For techniques, you can:
- use sorbate, if you didn't do ML and don't mind the taster/smell
- add lysozyme but on reds you'll likely get some deposit because
it'll interact with tannins
- sterile filter
- increase the alcohol content or lower the pH if those options are
okay for the wine
- bottle, store in cool environment and hope for the best

Pp


Thanks,
Charles

On Jan 12, 3:14*pm, Charles E wrote:
Sterile filter sounds like the best option to me. Does that strip the
wine of any character?


Depends who you ask. Plus the setup is expensive, so you might want to
run a test first. If you can't get access to sterile filter unit, you
can try Buon Vino #3 as a rough approximation of the effect - the
sterile filter would be even finer in pore size but not by much.

Pp