Help with PH acid additions in banana wine

[DragonTail]

Trying to understand my PH reading for banana wine and adjust it. This should be simple math but something is off. Here is what I have. Please tell me what I am doing wrong (math included). Looking at the math two different ways.

Using this calculator: https://www.winebusiness.com/calculator/winemaking/section/5/

1) PH banana wine of 5.0. I read it should be around 3.3 for fermentation. Since 5.0 to 3.3 is 1.7. I add that to the acid rate addition.
Result is 6.44 g / gallon

2) Or... there are 17 "steps" or .1's from 3.3 to 1.7. Result would be 64 g/gallon
64 grams is allot of tartaric acid! Is this right?

I went with the assumption that #1 was too much so I added to the recipe before fermentation by method number one. PH went from 5 to about 3.9 which aligns with the lesser amount. But the more I read the more I am doubt my addition. But if it is the large amount, whey did my PH change so much with just 6.44 g/gallon?

Simply put is it just a simple start PH - desired PH (add acid per calculation of 1.7) or is it every .1 is a "step" (add acid per calculation of 17).

Couple other acid questions:

I am confused as to what acid I need to be using. Jack Keller's wine making book, specifically sites tartaric acid, but there are references to other types of acids to use (citric). I vaguely recall somewhere that you should use the acid that is the fruit you are using, but there are recipes where the fruit acid does not match the acid addition the recipe calls for.

Also confused about TA vs PH. The book I am using goes to great length to describe how to calculate TA. It references certain fruits and the TA of them, insinuating there should be adjustments to the TA. What is the point of discussing TA as a separate thing than PH? You if you adjust one, you are adjusting both since they are related. The implication is you can adjust TA independently of PH? You add acid, PH goes down and TA goes up correct? Basically what is the point of calculating TA? Super confused on this one.

Thanks for the help to anyone that responds to this. First batches went through with little consternation... I guess dumb and happy because I did not know what I was doing wrong. This round extremely frustrating because I am starting to see how little I know and how much I messed up the first time.

 

[winemaker81]

Acid adjustment is a difficult thing. pH is a logarithmic scale, so changes up and down do not make immediate sense to most folks. IIRC, pH 3.0 is 10 times more acidic than pH 4.0.

When I'm adjusting acid, I determine how much I need to add, and then add about 1/4 that amount. Stir well and test again. Why? I have found that I rarely need as much acid as I calculate. And because it's a lot easier to add more than to take some out.

There is no perfect pH for fermentation. It's a range, and a fairly wide one. Generally speaking, 2.9 is the lowest end of the range, as wine yeast don't do well in more acidic environments.

On the other end of the scale, it's more open to debate. Yeast is fine at pH above 4, but so are a lot of other hostile microorganisms. I typically aim for < 3.8. Some folks want a lower number, but IME 3.8 works fine.

Post-fermentation? I take readings, but all adjustments are by taste.

Which acid to use? Tartaric is the primary acid in grapes, so it's the one to add for grape wines, and I'll use it for fruit wines if I don't have a different one. Citric acid is common for many fruits, and malic is the one for apples that give them the tang.

Jack Keller did great things for the home winemaking community, and he deserves to be honored for that. However, his recipes are often considered low in fruit, and are not all of equal quality.

Keep in mind that many recipes are a record of what worked, not what's best. Next wine you plan to start, post the recipe and ask for feedback. Yeah, there will be disagreement, but you'll get information with which to make your own decisions.

pH and TA typically have a converse relationship, one goes up, the other goes down ... mostly. They measure completely different things, so in some situations they change oddly. TA is a measure of titratable acid, while pH is the ionization level.

 

[DragonTail]

Acid adjustment is a difficult thing. pH is a logarithmic scale, so changes up and down do not make immediate sense to most folks. IIRC, pH 3.0 is 10 times more acidic than pH 4.0.

When I'm adjusting acid, I determine how much I need to add, and then add about 1/4 that amount. Stir well and test again. Why? I have found that I rarely need as much acid as I calculate. And because it's a lot easier to add more than to take some out.

There is no perfect pH for fermentation. It's a range, and a fairly wide one. Generally speaking, 2.9 is the lowest end of the range, as wine yeast don't do well in more acidic environments.

On the other end of the scale, it's more open to debate. Yeast is fine at pH above 4, but so are a lot of other hostile microorganisms. I typically aim for < 3.8. Some folks want a lower number, but IME 3.8 works fine.

Post-fermentation? I take readings, but all adjustments are by taste.

Which acid to use? Tartaric is the primary acid in grapes, so it's the one to add for grape wines, and I'll use it for fruit wines if I don't have a different one. Citric acid is common for many fruits, and malic is the one for apples that give them the tang.

Jack Keller did great things for the home winemaking community, and he deserves to be honored for that. However, his recipes are often considered low in fruit, and are not all of equal quality.

Keep in mind that many recipes are a record of what worked, not what's best. Next wine you plan to start, post the recipe and ask for feedback. Yeah, there will be disagreement, but you'll get information with which to make your own decisions.

pH and TA typically have a converse relationship, one goes up, the other goes down ... mostly. They measure completely different things, so in some situations they change oddly. TA is a measure of titratable acid, while pH is the ionization level.

Thank you. So with my math above, I assume the correct answer is #2, so in my example, I would need 64 grams of acid, maybe a little less and not add all at once?

 

[winemaker81]

Thank you. So with my math above, I assume the correct answer is #2, so in my example, I would need 64 grams of acid, maybe a little less and not add all at once?

Regarding 6.44 g/gallon reducing the pH from 5.0 to 3.9? That seems like a large drop.

However, as I said, pH 4.0 is 10 times as acidic as pH 5.0, so it will take ~10 times as much to go from 4.0 to 3.0, so the numbers may be correct. I've never adjusted a must from a pH that high so this is what I hope is educated guesses on my part.

If it were me, I'd stir very well and test the pH again, 3 times from different places in the must. If you get different readings, stir again, and repeat the tests.

I proved to my own satisfaction that what I thought was a well stirred must, wasn't. When you think you've stirred enough, stir it again.

If the pH is accurate, I'd add another 6g/gallon to see what happens. Because pH is a logarithmic scale, it should make a lot less difference.

It's very possible to get into an acid adjustment yo-yo, with overcorrecting in both directions. This does not end well, hence my suggestion to go slowly.

 

[Raptor99]

If it were me, I'd stir very well and test the pH again, 3 times from different places in the must. If you get different readings, stir again, and repeat the tests.

I have found that it sometimes takes a while for the acid to fully integrate into the must, so I usually stir it well, wait several hours or overnight, stir well again, and then take another pH reading.

 

[DragonTail]

Thanks for the advice on stirring and waiting for the acid to integrate.

I have another 1 gallon batch going. Say I want to go Need to go from a PH of 4.1 to a PH of 3.9 and I want it in grams. Using the calculations I mentioned above, what is the correct amount?

a) 1 gallon, 4 .1 to 3.9 is 2 steps so 7.57 grams added

or

b) 1 gallon, 4.1 - 3.9 = .2 so .76 grams added

I get what you are all saying about the acid integrating / time and stirring, I am trying to understand the math. So would I add 7.57 grams or .76 grams to go from PH 4.1 to 3.9?

 

[Raptor99]

pH is a logarithmic scale, so I'm not sure that you can calculate it like that. @Rice_Guy might be able to shed some light on that.

 

[sour_grapes]

In addition to the fact that pH is logarithmic, the amount that a given amount of acid will change the pH will vary from batch to batch, and depends on other things in the wine. We call this "buffering." The best analogy I have been able to come up with is to think about a narrow river valley. If you add a volume of water to it, the level will rise. If the canyon walls are narrow, the water level will rise a lot; if the valley is a little broader, it will rise a lot less.

 

[Rice_Guy]

* practically speaking we can assume that (distilled) water is transparent when measuring pH or TA. Your first question for this calculation would be what percentage of dry solids in your must. ,,, ie if it is thin it won’t take much to push the pH either up or down.

* buffering is a term which describes how much of a substance it takes to push the pH. Buffering is a function of which acids and how much acid and salt is is a beverage (ie percentage dry solids). For factory folks this could be how many grams of solids in a liter of that juice. Or am I buying a concentrate of said juice.
BUT not all juices have the same percentage of acid and salt in a gram of dry solids. As an example I once made banana water with 519 gm of banana and 300 ml of distilled water. The measured pH was 5.14, the TA was 0.19% (calculated as tartaric). For your desire to push pH this means that one liter of this banana water is as potent as 1.9 gram of tartaric acid. ( pH was pushed from 5.14 to 8.2). as a contrasting situation I have tested Real lime with pH of 2.62 and a TA of 5.83%. ,,, this means one liter of this grocery product is as potent as 58.3 grams of tartaric acid. (pushing pH from 2.62 to 8.2)

* my first tool for guessing how many grams of acid it would take to push the pH down is the titratable acidity (TA). With TA I can guess what percentage solids (acid and salts) is in a product.
* my second tool for guessing how many grams of acid to push the pH is what crop? Vendors sell juices based on sugar (total solids) specifications, (degrees Brix),,, and % acid etc. (proportional to ripeness). BUT every crop is different so this is a guess.
* back to buffering, there are many food grade acids. Citric acid has three H+ that can be pulled off. Malic acid has two H+. Lactic acid has one H+. Each H+ is pushed off creating a salt of that acid at a location called the pKa. The percentage of each acid varies on ripeness, ex malic acid decreases as grapes ripen. Not all acid products are the same, ex there is variation percentage acid makeup in “acid blend”
* the easy way to change pH is add a little and see how much the pH changed.
* if the grams is critical (ex I have 10,000 gallons in a tank and FDA requires pH under 4.0,) ,,, the only way to be accurate is to take the juice and titrate with the acid ingredient I am formulating with.

 

[DragonTail]

So I take it this is overly simplistic and inaccurate? https://www.winebusiness.com/calculator/winemaking/section/5/
Would this get me in the ballpark? If so, which is correct... the x number of steps (a) above, or (b) above... simple PH math.
Book reference I am using prescribes the same way. Misleading information from the site and book if this doesn't work.

I assume this calculator and my book reference are based on this (information information I am going by is in green).

*1.0 g/L addition of Tartaric acid will increase the TA by about 1.0 g/L and will decrease the pH by 0.1 pH units.

*1.0 g/L addition of Malic acid will increase the TA by about 1.12 g/L and will decrease the pH by 0.08 pH units.

*1.0 g/L addition of Citric acid will increase the TA by about 1.17 g/L and will decrease the pH by 0.08 pH units.

 

[DragonTail]

Loving this discussion by the way. You all are an awesome source of knowledge.

 

[Rice_Guy]

*1.0 g/L addition of Tartaric acid will increase the TA by about 1.0 g/L and will decrease the pH by 0.1 pH units.

*1.0 g/L addition of Malic acid will increase the TA by about 1.12 g/L and will decrease the pH by 0.08 pH units.

*1.0 g/L addition of Citric acid will increase the TA by about 1.17 g/L and will decrease the pH by 0.08 pH units.

This will get you in the ballpark as long as you have a juice which is nominally TA 0.6 to 0.7%.
Your post mentioned banana, my one look at banana (~60% solids) had a TA of 0.19%, ,,, Keller recipes are thinner, ,, I will guess your banana was very ripe.

Ballpark guessing your calculation using a grape juice model is 5 times the desired pH treatment.
Changing TA is a straight numbers calculation. Putting a gram of tartaric in a liter of must increases the TA by one gram per liter. ,,, and the molecular weight calculation for malic or lactic or phosphoric or citric are always constants.

 

[DragonTail]

This will get you in the ballpark as long as you have a juice which is nominally TA 0.6 to 0.7%.
Your post mentioned banana, my one look at banana (~60% solids) had a TA of 0.19%, ,,, Keller recipes are thinner, ,, I will guess your banana was very ripe.

Ballpark guessing your calculation using a grape juice model is 5 times the desired pH treatment.
Changing TA is a straight numbers calculation. Putting a gram of tartaric in a liter of must increases the TA by one gram per liter. ,,, and the molecular weight calculation for malic or lactic or phosphoric or citric are always constants.

Yes, banana was super ripe. Should I have used less ripe ones?

 

[winemaker81]

Yes, banana was super ripe. Should I have used less ripe ones?

Nope, riper is good. This just illustrates that all recipes need to be examined.

And yes, this is not obvious for beginners. Fortunately for you, you came to the right place for help.

 

[BarrelMonkey]

So I take it this is overly simplistic and inaccurate? https://www.winebusiness.com/calculator/winemaking/section/5/
Would this get me in the ballpark? If so, which is correct... the x number of steps (a) above, or (b) above... simple PH math.
Book reference I am using prescribes the same way. Misleading information from the site and book if this doesn't work.

I assume this calculator and my book reference are based on this (information information I am going by is in green).

*1.0 g/L addition of Tartaric acid will increase the TA by about 1.0 g/L and will decrease the pH by 0.1 pH units.

*1.0 g/L addition of Malic acid will increase the TA by about 1.12 g/L and will decrease the pH by 0.08 pH units.

*1.0 g/L addition of Citric acid will increase the TA by about 1.17 g/L and will decrease the pH by 0.08 pH units.

Bear in mind that winebusiness.com is largely a resource for people making wine from grapes... Your rule of thumb highlighted in green is what i use as a starting point when deciding on adjustments to grape must, but even then as others have said, buffering capacity varies between different grapes (and even different harvests from the same vineyard) so caution is warranted. This buffering effect (plus the fact that different fruits have different acid components) goes a long way to explaining why, although pH and TA have an inverse relationship, you can't automatically predict one from the other.

 

[RylanJacobs]

OP, it seems you have made up your mind that you want to make the acid adjustment. I understand that you are asking about the correct measurements for the pH adjustments. The previous replies are helpful in answering that question.

I would caution you against "chasing numbers" when it comes to must adjustments such as pH. Why not 3.4, 3.2, 3.5, etc.? When it comes to pH, I tend to focus on 3 things:

1) yeast parameters for alcoholic fermentation
- If the pH is too high for the yeast, I would make only the minimum adjustment necessary to bring it into range.

2) microbial stability (in conjunction with adequate sulfite use)
- If the pH is too high to achieve microbial stability without adding excessive amounts of SO2, then I'll make the minimum adjustment needed to achieve microbial stability with an appropriate dose of SO2. (Generally, this is a pH of 4.0 or less with about 90ppm SO2). SO2 is typically undetectable when it is less than 150ppm. Some on this board will disagree. Your mileage may vary.

3) taste
- This one is important, but is least reliant on the numbers. This would simply involve making acid adjustments in very small quantities until you achieve your desired tasting profile. Obviously this can only occur after primary fermentation.



Anyways, you've already gotten lots of great insight from this board. My advice would be to limit your pH adjustments to only what is absolutely necessary, and I certainly would never chase a specific pH range because of a reference text.

 

[winemanden]

81, you're right IMO.

Post-fermentation? I take readings, but all adjustments are by taste.

I've always done it like that. After all, it's my wine, so I make it to MY taste!