# Adding fruit juice after finished fermentation



## Rappatuz (Apr 13, 2019)

Okay. So I'm planning to make a weird wine out of root vegetables, tomato and lemon. The ingredients aren't really the point here. Let me explain ... 

Usually I toss in all ingredients, add yeast, and let the process run its course. With this recipe I want the fermentation to run with root vegetables in the bucket and add tomato and lemon juice after it has finished. 

Why? 

Several sources tell me that fermentation converts citric acid into the sour tasting acetic acid found in vinegar. Because the dominating acid in tomatoes and lemons is citric I'm considering adding their juices after fermentation has finished. The post-fermentation addition will probably make up 10-15 % of the final volume. Of course the wine will become somewhat diluted. I'll make up for that up front. 

Has anyone tried out this approach and what was your experience? May this approach somehow create any problems? Is my point about acid conversion valid? 

-Rappatuz


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## tradowsk (Apr 14, 2019)

I don't think you're right in saying that citric acid is converted to acetic acid during fermentation. I recently made a mead with added fresh lime juice (high in citric acid) and had no vinegar characteristics in the resulting mead. I know if your sanitization isn't good you can introduce bacteria into the wine that convert alcohol into vinegar, but citric acid is in a lot of fruits/vegetables that people ferment all the time.

But I would be interested in reviewing your sources on this as I am by no means an expert winemaker.


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## Rappatuz (Apr 14, 2019)

tradowsk said:


> I don't think you're right in saying that citric acid is converted to acetic acid during fermentation. I recently made a mead with added fresh lime juice (high in citric acid) and had no vinegar characteristics in the resulting mead. I know if your sanitization isn't good you can introduce bacteria into the wine that convert alcohol into vinegar, but citric acid is in a lot of fruits/vegetables that people ferment all the time.
> 
> But I would be interested in reviewing your sources on this as I am by no means an expert winemaker.



Good to hear your mead turned out fine (non-vinegary). 

The wikipedia page on "Acids in wine" states the following: *"When citric acid is added, it is always done after primary alcohol fermentation has been completed due to the tendency of yeast to convert citric into acetic acid."* The source is "The Oxford Companion to Wine". 
URL: https://en.wikipedia.org/wiki/Acids_in_wine

Jack Keller's article "Acidity in wine" tells us that: *"Citric acid added to a must before fermentation will largely be lost during fermentation. Thus, it is best to add it after all signs of fermentation have disappeared."*
URL: http://winemaking.jackkeller.net/acid.asp

I'm considering splitting the batch into two smaller batches, one with all ingredients added before fermentation, and one where I add tomato/lemon juice after completed fermentation. A nice experiment. 

Of course there may be a re-fermentation on the added juices, but it'll probably be small scale. Mass wise, tomatoes contain about 2.6 % sugar, lemons about 2.5 %.


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## Johnd (Apr 14, 2019)

I’m not able to access The Oxford Companion to Wine, as it’s a publication for sale, but wanted to try to see the context in which the comment was made and subsequently extruded for Wiki. 

My understanding of the citric to acetic conversion is that it’s done by LAB in the MLF process, it’s an intermediate step that ultimately produces diacetyl in our wines. See attached from UC Davis: https://wineserver.ucdavis.edu/indu...chniques/common-chemical-reagents/citric-acid

Seems to my simple mind that if during AF, all yeast turned citric acid into acetic acid, we’d never be able to perform AF on any fruits with large concentrations of citric acid without making vinegar. 

I know that wine contains small quantities of acetic acid and there is an acceptable range. My understanding is that the creation of vinegar (acetic acid) is the result of actions by acetobacter, poor sulfite management, and exposure to oxygen.


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## Stressbaby (Apr 14, 2019)

Research this more to confirm, but generally it's bacteria, not yeast, which convert citric to acetic acid. 
Skeeter Pee and Dragon Blood are all lemon juice, and they don't wind up as vinegar.
Keep the SO2 up and it's not a problem. 

While I was typing @Johnd cross-posted, good to see we are in agreement.


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## sour_grapes (Apr 14, 2019)

Rappatuz said:


> The wikipedia page on "Acids in wine" states the following: *"When citric acid is added, it is always done after primary alcohol fermentation has been completed due to the tendency of yeast to convert citric into acetic acid."* The source is "The Oxford Companion to Wine".
> URL: https://en.wikipedia.org/wiki/Acids_in_wine



I also lack access to The Oxford Companion to Wine. However, I do not at all think that the Wiki article is citing the OCW as the source of that assertion. Here is what the Wiki article actually says:



> When citric acid is added, it is always done after primary alcohol fermentation has been completed due to the tendency of yeast to convert citric into acetic acid. In the European Union, use of citric acid for acidification is prohibited, but limited use of citric acid is permitted for removing excess iron and copper from the wine if potassium ferrocyanide is not available.[6]



The "[6]" refers, of course, to the OCW. Those two assertions are completely unrelated. There is a vanishingly small chance that BOTH assertions originate in the reference [6].


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## Rappatuz (Apr 14, 2019)

You are probably right. I just find it weird that two rather serious sources would get it wrong. 

For those of you who's made wine of citric fruit, did the citric flavor remain?


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## Rice_Guy (Apr 14, 2019)

Rappatuz said:


> You are probably right. I just find it weird that two rather serious sources would get it wrong.
> 
> For those of you who's made wine of citric fruit, did the citric flavor remain?


Yes
The flavor of citric acid Is distinctive, harder, citrus like, yes the citric acid flavor remains in finished wine. That said I have switched from using the free citric acid from work to a smoother flavor from tartaric when I make wine. Also I have not noted a wierd shift in pH back then.

Microbiology did not point out that yeast metabolize citric. A guess is that this is a yes “IF” situation. Most species of yeast will not metabolize citric acid , and All species of saccharomyces which are sold for the production of alcohol are selected to minimize that metabolism. If we look far enough we can find an organism which will metabolize just about anything.
In all the texts I’ve read no one has suggested holding citric acid back or there is a known quality defect related to when citric acid is used. I like what I have read from Jack Keller and would trust him and ask “under what conditions”. This is a good curiosity to research when I can’t sleep.


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## Rappatuz (Apr 15, 2019)

Rice_Guy said:


> Yes
> The flavor of citric acid Is distinctive, harder, citrus like, yes the citric acid flavor remains in finished wine. That said I have switched from using the free citric acid from work to a smoother flavor from tartaric when I make wine. Also I have not noted a wierd shift in pH back then.
> 
> Microbiology did not point out that yeast metabolize citric. A guess is that this is a yes “IF” situation. Most species of yeast will not metabolize citric acid , and All species of saccharomyces which are sold for the production of alcohol are selected to minimize that metabolism. If we look far enough we can find an organism which will metabolize just about anything.
> In all the texts I’ve read no one has suggested holding citric acid back or there is a known quality defect related to when citric acid is used. I like what I have read from Jack Keller and would trust him and ask “under what conditions”. This is a good curiosity to research when I can’t sleep.



The reason I want to use tomato and lemon is because it's going to be a 'sea food' wine. Those flavors usually go very well with sea food. But I'm not going crazy with the amount, about 10-15 % of the total volume. If the taste becomes very 'hard' I may take the lemon out and replace with tartaric acid on my next try.

Good information about yeasts metabolizm of acid. I have a book on wine making that I haven't yet started. I'll check if it says anything about the subject.


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## BernardSmith (Apr 15, 2019)

Sounds like the OCW is referring to commercially fermented grape wine where the vintner is adding citric acid for some reason or another and so rules and regulations may be playing at least as much importance here as chemistry. But that said, Wikipedia is viewed by anyone as a source of factual information? That's a little like a doctoral candidate citing a children's encyclopedia as a reference. Sorry, but I prefer my sources to be by-lined and peer reviewed and not edited and written and then rewritten by anonymous self-proclaimed experts with all kinds of axes to grind. But even then, peer review does not completely prevent garbage from seeping through but it does make it a hell of a lot harder to get nonsense published.


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## Scooter68 (Apr 15, 2019)

Trying to understand what is meant by "Sea food wine". Is this a wine to be served with or on sea food? A wine vinegar perhaps?

Guess I'm still too old school with my thinking about wine - that just because you can ferment something into "wine" doesn't mean you should.

Sorry if this sounds harsh - blame it on the drugs - recovering from TURP procedure this morning.


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## BernardSmith (Apr 15, 2019)

A vegetarian, but my reading is that this is a wine used to marinade or cook sea food


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## Scooter68 (Apr 15, 2019)

Ok, got it now that makes sense. A Cooking wine.


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## sour_grapes (Apr 15, 2019)

Scooter68 said:


> recovering from TURP procedure this morning.



Had to google that, and, all I can say is "take care, you poor bastard!" Best of luck.


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## Johnd (Apr 15, 2019)

sour_grapes said:


> Had to google that, and, all I can say is "take care, you poor bastard!" Best of luck.



I googled it too, wish I hadn’t, hurts to read.


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## Scooter68 (Apr 16, 2019)

But the pain drugs are *GOOD. 

And it wasn't cancer. That's Always good news.*


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## Rice_Guy (Apr 16, 2019)

Rappatuz said:


> The reason I want to use tomato and lemon is because it's going to be a 'sea food' wine. Those flavors usually go very well with sea food. But I'm not going crazy with the amount, about 10-15 % of the total volume. If the taste becomes very 'hard' I may take the lemon out and replace with tartaric acid on my next try.


Every R&D product I have seen starts with a model system to play with flavors so that development time is reduced. 

If as Bernard suggests, the end is a marinade I would skip fermentation and build marinades. Wet food products (shelf stable sauces) meld flavors therefore pilot tests had to be aged a week before evaluating the likability of a formula.
Marketing folks actively sampled US and overseas for ideas, , as a home wine maker I sample wineries, the vinters club, restaurants, etc. for new mixtures that look promising. example; a flavor for salmon that has turned into a standard in this house started as a Tamarand curry at an Indian restaurant, the US ingredient version was built with apple concentrate/lemon juice/mushroom base/spices. 
I do sampeling for drinking wine too. The overall thought is to blend natural ingredients to accomplish stability rules like pH and alcohol without going to the chemical supplier for things that shoe horn the product. example; The favorite table wine out of 2017 was concord/elderberry— concord was there for lots of aroma and the elderberry was there for long tannic flavor notes.

This sounds like a fun project. Would be nice to see a bottle show up at Vinters meeting or at contest so I could try it. (copy the concept)


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## sour_grapes (Apr 16, 2019)

Sorry for the threadjack, @Rappatuz 



Scooter68 said:


> *And it wasn't cancer. That's Always good news.*



Yay, very glad to hear.

Now back to our regularly scheduled programming.


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## Scooter68 (Apr 16, 2019)

Rice Guy - I agree. The flavors in a marinade seem to me to be stronger than those that a wine could provide. Certainly a wine of some variety added to a marinade could lend a hand in tenderizing during cooking but the marinade has much stronger flavors than a wine could impart. I would suggest a creating more simple wine variety and a marinade to accompany the wine.


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## garymc (Apr 17, 2019)

If citric acid is turned into acetic acid, I'm not using any more acid blend in my wine. I sure would have thought the companies that make that stuff would know better than to make it with 50% citric acid.


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## Rice_Guy (Apr 17, 2019)

garymc said:


> If citric acid is turned into acetic acid, I'm not using any more acid blend in my wine. I sure would have thought the companies that make that stuff would know better than to make it with 50% citric acid.


As wine makers we fight the conditions that create acetic acid, , , generally called exposure to excess oxygen with naturally occurring bacteria.

If yeast could metabolize anaerobic citric acid and produce acetic acid in levels that are detectable (ppm), , , everyone one this list would decide not to use it the first time tried , , , everyone on this list would avoid country wine , , , and grandpa a hundred years ago would have advised that fruit wines are a really good preservative but don’t ever try to drink them.

Our collective experience is oxygen is the risk factor for acetic acid.


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## Rice_Guy (Apr 17, 2019)

a reference: Wine Faults, Causes, Effects, Cures; John Huddleston Ph.D. 2011, 
“causes of Acetic Acid
Numerous microbes produce VA in wine, the most important being the following:
* Acetobacter and Gluconobacter, which are aerobic (oxygen requiring) bacteria.
* Lactic acid Bacteria (LAB), although some varieties more than others.
* Wild yeast strains, such as Kloeckera apiculata, Pechia membranaefaciens and, to a lesser degree, some strains of Saccharomyces cerevisiae.
* Pediococcus bacteria, which are anaerobic and, therefore, a concern after bottling.
* Botrytis, which is found on damaged fruit, usually as a result of Acetobacter, which is carried in by fruit flies and bees.
* Brettanomyces and its telemorph Deckers cause acetic acid in the presence of oxygen.”

the key is the phrase SOME STRAINS . . of S cerevisiae.
_Unfortunately this reference doesn’t mention citric acid metabolism
_
The next reference for overall reactions is Concepts in Wine Chemistry, second edition, Yair Margarita Ph.D, , , , ? where did I put it? ?


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## Scooter68 (Apr 17, 2019)

Wikipedia as a scientific source is about as trustworthy as the kid on the playground description of 'how to seduce a woman.'

Similarly there are endless publications on all kinds of topics (Often self-published) and especially YouTube videos that do more to demonstrate how ignorant people can be. Sadly many are out to make money or they just haven't got a clue - in the past year alone I watched a number of those "Living Off-the-Grid" YouTubers who repeated demonstrated how NOT to do things while thinking they are 'helping' others.
_
MY POINT: When investigating a subject to learn 'how to' proceed with caution and investigate as many sources as possible. Relying on just one or two sources can still provide you with info that is dead wrong or simply incomplete. _


The acetic acid problem arises only when a wine maker allows the conditions and materials (bacteria) to produce acetic acid to exist in their wine. Thousands, probably millions, of people have made wine quite successfully with citric acid in a large percentage in their wine. It only takes a few reasonable precautions to prevent the problem from ever ruining a wine. Acid Blend contains citric acid because it works, not because it's cheaper or easier.


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## BernardSmith (Apr 17, 2019)

I would go even further than that Scooter68. Acid blend contains citric acid because many, many fruits contain citric acid and if you are making wines from those fruits you may want/need to add some additional acidity, but
if you added only tartaric acid - the dominant wine in grapes, or malic acid, the dominant wine in apples your wine would take on flavors that would be somewhat alien. Adding either citric acid or a blend that includes citric acid means that the flavors coming from the acid additions better match the fruit "substrate".


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## stickman (Apr 18, 2019)

As was stated earlier, using citric acid doesn't automatically cause VA. The main issue is when citric acid is added to a wine that is intended to go through ML fermentation. Generally wines going through ML are not protected by so2 until after completion, so the citric acid is at risk of being consumed. Excess diacetyl (butter aromatic) may be produced as well as an increased risk of higher than normal levels of VA. Much depends on the wine pH and the microbes present.

The following is from Lallemand, DR. SIBYLLE KRIEGER.

"Trials conducted using simultaneous bacterial and yeast inoculation vs. bacterial inoculation upon completion of the alcohol fermentation showed no significant difference in the final acetic acid concentration, but a direct relationship between citric acid degradation and an increase in acetic acid concentration was demonstrated. Depending on the availability of oxygen and the oxidation-reduction potential of the medium, citric acid can either be used as an electron acceptor, which will result in acetic acid production, or it can be degraded to diacetyl."


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## jgmillr1 (Apr 18, 2019)

stickman said:


> The main issue is when citric acid is added to a wine that is intended to go through ML fermentation.



Bingo


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