Wildbilly wrote:

> In article >,
> "Paul E. Lehmann" > wrote:
>
>> Wildbilly wrote:
>>
>> > 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.
>>
>> WHOA, Wildbilly. Are you sure of your units? I believe that one POUND
>> of
>> Potassium metabisufite would give you a LOT more that a 5% solution. Try
>> 100 GRAMS in one LITER for a standardized solution. This is a 10%
>> solution. See
>>
>> http://www.brsquared.org/wine/Articles/SO2/SO2.htm
>>
>> section 19 on the details.
>>
>> Paul
>>
>>
>> > 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.
>
> 19. Stock Solutions, third paragraph, fifth line, "Since potassium
> metabisulphite is only 57.6% SO2," your 100 grams per liter is a 5.76%
> solution. My suggestion was 1 pound of metabisulfite/gallon H2O. A
> gallon is eight pounds plus the pound of metabi = 9 lbs. 1/9 =
> 0.11111111. Mutiply this by the efficency of 57.6%, (1/9) X .576 = 6.4%
> SO2. This is wine making, not rocket science. If you are trying for 32
> ppm and get 30ppm or 34ppm, it's no big deal.
>
> You'll also notice I was much more bref than
> http://www.brsquared.org/wine/Articles/SO2/SO2.htm ;O)

The above link takes the 57.6%, you correctly reference, into consideration
when he gives the formulae for additions using the "Stock Solution" he
makes.