Trying to lower CO2 from 50 to 20 in order to start MLF in my merlot. I
"dribbled" it in a long thread of juice about two feet long from one
secondary carboy to another with lots of foam. It only dropped to 40ppm and
I suppose I oxidized the hell out of it, if that matters. I would guess 40
is still twice too high. I read that H2O2 works with one ml of 3% peroxide
per gallon to lower the CO2 by 10, but I also recall that the problem here
is that the peroxide kills the ML germ. I have four more carboys to go so I
would certainly appreciate some advice as to how to proceed......

Thanks,
Bruce

"Bruce" > wrote in message
news
>
>
> Trying to lower CO2 from 50 to 20 in order to start MLF in my merlot.

I would guess that you mean SO2 - not CO2.

I
> "dribbled" it in a long thread of juice about two feet long from one
> secondary carboy to another with lots of foam. It only dropped to 40ppm
and
> I suppose I oxidized the hell out of it, if that matters.

What you oxidized was the free SO2. That's how it protects the wine from
oxidation. The free SO2 sacrifices itself to consume the oxygen. The
product is an insignificant amount of sulfuric acid.

I would guess 40
> is still twice too high. I read that H2O2 works with one ml of 3%
peroxide
> per gallon to lower the CO2 by 10, but I also recall that the problem here
> is that the peroxide kills the ML germ.

Peroxide is an even more drastic treatment than aeration. Why don't you try
aerating the heck out of one carboy to bring down the SO2, inoculating that
with ML, and once it's going "feed" it with the wine from the other carboys?
Once the ML gets going, it'll tolerate a little shot of SO2 at a time, and
purge it in the leaving gas stream.

Depending on the pH, 50 ppm may not really be that high. If the wine is at
pH 3.2 and 50 ppm free, I'd say it's unlikely that it'll ever go ML. OTOH,
if the pH is 3.7 or so and 50 ppm free, you probably couldn't _stop_ ML if
you wanted to!

Tom S

Tom.....

> I would guess that you mean SO2 - not CO2.

Yes, I meant SO2... Getting old...

> What you oxidized was the free SO2. That's how it protects the wine from
> oxidation. The free SO2 sacrifices itself to consume the oxygen. The
> product is an insignificant amount of sulfuric acid.
>
> Peroxide is an even more drastic treatment than aeration. Why don't you
try
> aerating the heck out of one carboy to bring down the SO2, inoculating
that
> with ML, and once it's going "feed" it with the wine from the other
carboys?
> Once the ML gets going, it'll tolerate a little shot of SO2 at a time, and
> purge it in the leaving gas stream.
>
> Depending on the pH, 50 ppm may not really be that high. If the wine is
at
> pH 3.2 and 50 ppm free, I'd say it's unlikely that it'll ever go ML.
OTOH,
> if the pH is 3.7 or so and 50 ppm free, you probably couldn't _stop_ ML if
> you wanted to!

pH was around 3.6 I think. Surprised that there isn't something on the
market somewhere that gives accuracy to 0.1. Both pH and TA measurments
seem subjective. SO2 titrates seem more accurate once you become practiced
at it.

Anyhow, thanks for the advice Tom. I'll try filling the five-gallon
carboys half full and shaking the hell out of it. I have an air compressor
and could put a hose to the
bottom of the carboys. That should do it!

Cheers,
Bruce


>
>

"Bruce" > wrote in message
...
> pH was around 3.6 I think. Surprised that there isn't something on the
> market somewhere that gives accuracy to 0.1. Both pH and TA measurments
> seem subjective.

Not really, if your lab technique is good. Takes practice and a good pH
meter. There are relatively inexpensive meters that read to 0.01 pH units.

> SO2 titrates seem more accurate once you become practiced
> at it.

I assume you mean Titrets. For white wines I prefer a straight Ripper
titration, but for reds they're OK. Ripper is really hard to do on reds. I
plan to get the apparatus to do vacuum aspiration eventually.

> Anyhow, thanks for the advice Tom. I'll try filling the five-gallon
> carboys half full and shaking the hell out of it. I have an air
compressor
> and could put a hose to the
> bottom of the carboys. That should do it!

I wouldn't get as drastic as that. Besides, air compressors have a lot of
hydrocarbon (oil) in their exhaust unless they're well filtered. Bubbling
nitrogen through the wine would be better.

At pH 3.6, I'd say the ML will go with more free SO2 than you think. Just
get one carboy going good and use that to start the others. Heavy aeration
of all your carboys isn't a good idea.

Tom S