In article >,
"Paul E. Lehmann" > wrote:
> fishziblu wrote:
>
> > it is my second go at making wine,and i've noticed that after the
> > first fermentation,the ph increases. When i crushed the grapes my
> > reading was 3.4, however on my first racking the ph has gone up to
> > 3.9. Is there a reason for this? Should i check the wine more often? i
> > have added some tartaric now. During the time it spent with a high ph
> > could it spoil itself?
> It is common for the pH to rise during or after fermentation. If you did not
> add any Malo Lactic culture, your grapes probably underwent a ML fermention
> from the natural culture on the grapes. You did the right thing by adding
> tartaric. You also need to protect your wine with SO2 and the amount you
> use depends on the new pH of your wine after you added the tartaric.
Good news is that the pH is just about right for Robert Parker;O)
You need some way of measuring the "free" SO2. The Ripper method calls
for a starch indicator, sulfuric acid, an Erlenmeyer flask, and a
burette. Otherwise you risk O.D.ing your wine on SO2. Nothing like 100
parts per million (ppm) of SO2 in your wine to give you a blinding
headache.
For the addition, I use 1 lb potassium metabisulfite per 1 gallon of
water to make a 5% solution. Then the formula is ppm of SO2 that you
want to add, times the gallons added to, times the fudge factor of .063
equals the number of milliliters of 5% SO2 solution to add (#ppm X
gallons X .063 = # mls). Initially the SO2 will bind to aldehydes,
sugars, proteins, etc. and you won't see the number of ppm of SO2
expressed, but once these compounds become saturated with SO2, you'll
get more of a linear response. The bound SO2 has little effect on
micro-organisms, which is the job of the "free" SO2. The effectiveness
of the SO2 is dependent on the pH of the wine. For a pH of 3 to 4, use
30 to 40 ppm SO2. This is a rough rule of thumb but should serve you
well.
--
"When you give food to the poor, they call you a saint. When you ask why the poor have no food, they call you a communist."
-Archbishop Helder Camara
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