by the sounds of it, you should do that before adding the yeast.... I just started a batch and wasn't aware of the ph factor... and now my acid is a bit too high... so now I have to wait and perhaps cold stabilize after fermentation is all done... or later add potassium or calcium carbonate...
I would do it before adding the sugar.... before fermentation... Rick
Make *all* your measurements before adding anything - it makes for more consistency in your measurements batch-to-batch. I don't think that the addition of sugar will make too much difference to the acidity/pH of the must, and certainly not enough to greatly affect what you'll need to add. Mix well, and then if you plan on making confirmatory measurements, do it after you've made all the adjustments you think you need.
For certain, any changes you make to the chemistry, try to do as early as possible in the process - before you start fermentation is best. The later you adjust, the less chance the adjustments will have time to "marry in" to the rest of the wine. The working of the wine by the yeast is a very active time for the wine, so it helps to integrate everything
A word of advice, be judicious with adjustments. I had a chemistry professor who's catch-phrase was "well, if some is good, then more must be better." This was usually 15 seconds before something exploded, and I think the same can apply to winemaking. If you're within an acceptable range(say +-.05 TA, maybe a little more, to the goal measurement), it's probably not worth the risk of further adjustment. If you're way off (say, +- 0.30 TA), you've got to do something, obviously.
At this point the best advice I can give to both you and Rick is that unless or until you learn the basics of "country" wine making, you should stick strictly to kits and/or proven recipes and follow the directions *exactly*. This way the only thing you will need to know is how to use a hydrometer. Lots of folks are quite happy just doing it this way and are successful winemakers without ever having to learn anything more about winemaking. My further comments are interspersed below........
Welllll...There are two ways to reduce acidity. Dilution and/or chemical (carbonates). If you choose dilution, you take a reading, calculate the amount of dilution required, make that dilution, and then retest to confirm that your estimates were correct. OTOH - if you choose chemical reduction, you have to *completely* assemble the must (so there is no subsequent dilution), *then* take a reading, calculate the amount of carbonate required, add the carbonate, and retest to confirm.
Yes, of course. They can be found in any book that concerns itself with basic winemaking practices.
Yes, but it depends on which procedure you choose. HTMS
Please see my comments to Mark (above in this thread). Further comments interspersed.......
Let me try to explain some aspects of acid management. TA is merely an empirically established *guideline*. Very helpful but certainly not critical to success. OTOH - pH *is* critical to success because it determines if the wine will have microbial stability. This is why Joanne has stressed the importance of pH in the other thread. While a pH meter is certainly the preferred way to check pH, the papers you have are perfectly adequate for doing this if you don't want to spend the money for a meter (they ain't cheap).
See my comments to Mark on acid reduction.
As Ben mentioned in the other thread, you will receive no benefit by cold stabilizing this wine. "Tartaric" wines *must* be cold stabilized. "Non-tartaric" wines (which your wine is) cannot form bitartrate crystals because there is no tartaric acid present to combine with the potassium. The reason that wines are categorized as "tartaric" or "non-tartaric" is because acid management is radically different for these two types. The above is just one aspect of this. HTMS
Novices might find this a little confusing, so let me please add a short explanation here.
TA and pH are measures of *concentration* (not quantity). Thus, anytime that you add something that increases the *volume* of the must, the "quantity" of acid present remains the same, but the "concentration" changes. Which of course is why dilution can be used to adjust acidity. HTMS
There may be some confusion about molecular sulfur dioxide levels and the microbial stability of wine.
When sulfur dioxide is added to wine, some sulfur dioxide combines with other materials in the wine and becomes bound or "fixed." The remaining sulfur dioxide is in the "free" form. The free sulfur dioxide exists in three different forms, the molecular form, the bisulfite form and the doubly ionized sulfite form. In general, only the molecular sulfur dioxide is effective against wine microbes, and many winemakers try and maintain a level of 0.8 milligrams of _molecular_ SO2 per liter of wine. But, the fraction of free sulfur dioxide that exists in the molecular form is strongly dependent upon the pH of the wine. Consequently, winemakers are always interested in wine pH so they can tell how much of the SO2 exists in the molecular form.
Unfortunately, many wine microbes can tolerate much higher levels of SO2. Some yeast strains, such as Saccharomyces bailii, can maintain normal fermentation rates when more than 200 ppm of SO2 are present (see Rankine, Making Good Wine, page 286). Vinegar bacteria are not very sensitive to SO2. "Sulfur dioxide has almost no effect on the acetic acid bacteria growth in the regular concentrations of SO2 in wine" (from Margalit, Concepts in Wine Chemistry, page 327).
So, the value of 0.8 milligrams of molecular SO2 per liter of wine is only a generalization and maintaining this level of SO2 certainly does _not_ guaranty microbial stability of any wine. In fact, the value of 0.8 mg/l is really only applicable to some of the lactic bacteria and some native yeasts.
I agree that what you are saying is technically correct but I think you are mixing apples and oranges. The definition of "an aseptic level" of molecular SO2, is the level which will kill (dead) all *anaerobic bacilli* normally found in wine. Things which are *not* "anaerobic bacilli" are dealt with by "other means". So - the SO2 tolerance of these "other things" has no relationship to "aseptic levels".
Vinegar bacteria is easy. It is *not* anaerobic, so it is dealt with by eliminating (severely limiting) the availability of atmospheric oxygen in the wine. Even though SO2 is not the agent that eliminates the bug, it helps by scavenging oxygen so it is not available for the bug to use.
While yeasts can function anaerobicly, they are not "bacilli", so they also fall outside the definition of "aseptic level of SO2". It is well known that the commercial yeasts we use are virtually *all* able to function at SO2 levels well above the levels we consider "aseptic" in winemaking. For this reason we deal with them by "other means". Namely, we eliminate all sugars so it has nothing to feed on (a dry wine) - or - we control it chemically (Sorbate/Benzoate etc) - or - we sterile filter - or - we can raise the alcohol level above the alcohol toxicity point of the yeast in question. HTMS
FWIW - the last I heard the "aseptic" level is now considered to be 0.83 ppm. Something about one of the bugs which_does_ fall within the definition was determined to have a slightly elevated tolerance. Can't even remember where I read that.
You are probably correct about my mixing apples and oranges. I seem to be easily confused these days. But, your definition...... "an aseptic level" of molecular SO2, is the level which will kill (dead) all *anaerobic bacilli* normally found in wine. Things which are *not* "anaerobic bacilli" are dealt with by "other means"........ seems a bit odd to me since "anaerobic bacilli" make up only a small part of anaerobic wine microbes. In general, the anaerobic bacteria found in wine belong to three genera, Lactobacillus (long rods), Leuconostoc (short rods) and Pediococcus (spheres). Why does your definition single out the long rods and ignore the short rods and spheres? Do you feel that only Lactobacillus cause wine problems?
BTW, can you give me a reference for the above definition?
I'm quite sure you are right. I am at the age now where I have already gone through my personal things and virtually all of my technical books and material have been donated to the public library. The only two books I still have on winemaking are an old copy of CJJ Berry and a small booklet that I sometimes loan out to folks that think they want to learn to make wine. So - the comments I make here are now based entirely on memory, and my memory certainly isn't what it used to be. :O(
Had to go look in the dictionary to understand what you meant here. You are right. I should not have used the word "bacilli" as its meaning is too narrow in this context. Sorry. Substitute "bacteria" or "bacterium" as appropriate.
Can't remember where I got the original definition. I can ask around, or go back to the library and try to find it, but I should think someone in this group would be able to provide such a reference.
I hope you don't think I was offended... i was just reading your back and forth very technical responses between two people who obviously know more about winemaking than I do or ever might... I'm really grateful for your help and your suggestions and advice...
But as I was reading your posts, I just had this picture, a la Wayne and Garth (Waynes' World) of them bowing down before people they truly admired and saying: I'm not worthy! I'm not worthy!..... So..... that's a bit of cultural context....
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