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.
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. Seesection 19 on the details.
Paul
You'll also notice I was much more bref than
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.
Uh, Paul, YOU said above, that 100 grams of metabi per 1 litre would give a 5% solution of SO2.
My point is that 1 lb/1 gallon is easier to remember than 86.8 grams/100ml (which you didn't). There is rarely a direct correspondence between SO2 added and SO2 measured. If you add 15ppm SO2 to a new wine, you may get a 5ppm or 10ppm of SO2 rise in the wine. If you want to remember 86.8g/100ml, go for it.
I think everyone gets it.
No, If you read the link you would see that one puts 100 grams in a liter container and fills it up to the one liter mark. In other words, it is 100 grams IN a liter not 100 grams TO a liter. Also it is not a 5% solution but a 10% solution.
I believe most amateur wine makers are more likely to have 100 grams on hand rather than one pound and the one liter solution will last a long time for most amateur winemakers. One gallon is a LOT to make - unless you use it to bathe with also :-)
True, I never argued the bound issue.
I think than anyone who wants to read and have a good knowledge will read the link I referred to. I am not interested into getting into a pissing contest with you but I would appreciate if you read the link instead of commenting off cuff. I belive the author has a LOT of knowledge on the subject.
I think we can agree that it is a 6.4% SO2 solution.
You will see that it is a 5.76% SO2 solution. (see below)
The calculations are here Paul.
(100g X .576)/1000g H2O = .0567 = 5.76%
This is wearisome. You made a statement, **"AND"** you gave a link
????? To paraphrase our murderous ex-vice president, "accuracy is a virtue".
I think everyone else gets it.
You are, and you have.
You don't think that someone might try a 1/4 lb in a quart? Don't even need a balance.
I read the link Paul, otherwise I wouldn't have been able to quote "19. Stock Solutions, third paragraph, fifth line, "Since potassium metabisulphite is only 57.6% SO2," ".
Yes it is a good site to begin learning about the technical side of wine making.
Don't think there is much more fun to be wrung out of this post. Bye.
Not to or for Wildbilly, but for anyone else following this thread:
To make a "Stock Solution" of potassium metabisulfite,
1) put 100 grams of potassium metabisulfite in a vessel that is graduated so that it indicates liters or parts thereof. 2) fill the container with water to the one liter mark and dissolve the potassium metabisulfite. You now have a 10% solution. 3) to calculate the amount of stock solution you need, use the following: so2 = ((ppm * liters) / 100) / .576where so2 is the amount of SO2 stock Solution in ml that you need to add.; ppm is your desired SO2 im ppm
be careful of the placement of the paranthesis when you do the math or put this in a spreadsheet.
example 1: you wish to add the necessary SO2 to give you 50ppm in one gallon if you plug in 3.785 liters in the above and do the math, the answer is 3.29 ml.
example 2: you wish to increase the SO2 in 5 gallons of wine by 25 ppm if you plug in 18.92 for liters the answer is 8.21 ml
remember that one gallon is 3.785 liters so make the necessary conversions Also note: that has been pointed out, that you do not need to make a liter, you can if you wish, for example, use 50 grams in 0.5 liters and still have the 10% solution.
The above does not include bounding that will occur and will be greater at small amounts. To see more of the details on this and pH considerations see the link at: Also take into account the pH of your wine
I'm glad it works for you, but can you define "fine"? I have never seen a commercial winery add potassium metabisulfate powder directly to wine (grapes, yes; wine, no). It is always hydrated first. Maybe they are all just dumb.
Why would anyone want to add 50ppm SO2 to their wine?
Besides being bacteriostatic, SO2 will bleach your wine, so you always want to use the minimum. At around 100 ppm, it will give you a sever head ache. For sensitive people, it may give them an asthma attack in the suggested 30 - 40 ppm range.
But if it works for you. Go for it.
Can you bray "reaction products"?
Well, I know where my elbow is, and I know where the ass is. I've been doing this commercially for over 30 years, without complaint.
Hey, Stoopid, listen up.
. . . the third and final factor behind the new American dumbness: not lack of knowledge per se but arrogance about that lack of knowledge. The problem is not just the things we do not know (consider the one in five American adults who, according to the National Science Foundation, thinks the sun revolves around the Earth); it's the alarming number of Americans who have smugly concluded that they do not need to know such things in the first place. Call this anti-rationalism -- a syndrome that is particularly dangerous to our public institutions and discourse. Not knowing a foreign language or the location of an important country is a manifestation of ignorance; denying that such knowledge matters is pure anti-rationalism. The toxic brew of anti-rationalism and ignorance hurts discussions of U.S. public policy on topics from health care to taxation.
There is no quick cure for this epidemic of arrogant anti-rationalism and anti-intellectualism; rote efforts to raise standardized test scores by stuffing students with specific answers to specific questions on specific tests will not do the job. Moreover, the people who exemplify the problem are usually oblivious to it. ("Hardly anyone believes himself to be against thought and culture," Hofstadter noted.) It is past time for a serious national discussion about whether, as a nation, we truly value intellect and rationality. If this indeed turns out to be a "change election," the low level of discourse in a country with a mind taught to aim at low objects ought to be the first item on the change agenda.
washingtonpost.com > Opinions > Outlook The Dumbing Of America Call Me a Snob, but Really, We're a Nation of Dunces By Susan Jacoby Sunday, February 17, 2008; Page B01
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