9 replies to this topic

[jonny84]

Hi all !

 

My name is John and i posted this new topic because i have a question with regard to the safe use of homemade vinegar.

Before going into further details, i would like to say a big thanks to all of you giving useful advice through ifsqn.com.

Your contribution is valuable and greatly appreciated !

 

I am an amateur wine maker and this year i decided to make red wine vinegar for the first time.

 

I followed the process summarized below:

 

1. Harvesting grapes 

2. Pressing/crushing grapes

3. Wine fermentation (no sulfites added)

4. Adding homemade mother of vinegar 

5. Vinegar fermentation

6. Removing mother of vinegar/ Filtering (with cheesecloth).

7. Storage of vinegar in the refrigerator (in 5 litres bottles, 15litres in total)

8. Executing infused vinegar recipe

9. Bottling infused vinegar in 250ml bottles

10.Kept refrigerated before/after use.

 

After step 7 (and before making the infused vinegar recipe), i got the acidity of the plain vinegar measured which was 3.5%. This percentage is lower than that stated in the local (Greece) and EU legislation (6% minimum). 

 

Furthermore, the infused vinegar recipe says that i have to simmer the vinegar together with the honey and figs. I think that the vinegar will lose part of its acidity -due to heating- and thus become even more weak. Therefore, i am a bit concern about its safety and fit for cosumption. I would like to ask the following:

 

> Are there any possible food safety (e.g. micobiological) issues related to low acidic homemade vinegars ?

> Is a homemade vinegar (heated and stored refrigerated) considered microbiologically stable, regardless of its acidity percentage ?   

> Is there any suggestion about the infused vinegar shelf life ? Is a two-month period acceptable, from a food safety perspective ?

  

Thank you very much in advance :-)

 

Kind regards

John

[MWidra]

> Are there any possible food safety (e.g. micobiological) issues related to low acidic homemade vinegars ?

> Is a homemade vinegar (heated and stored refrigerated) considered microbiologically stable, regardless of its acidity percentage ?   

> Is there any suggestion about the infused vinegar shelf life ? Is a two-month period acceptable, from a food safety perspective ?

  

Thank you very much in advance :-)

 

Kind regards

John

The low acidity of the vinegar will raise the effective pH, which will allow bacteria and mold to grow.  It is imperative to have the minimum acid content.  And if this is used to preserve other foods, those foods will not be protected.

 

I would say, from a food safety prospective, that until the vinegar is at the correct acidity, then it should not be considered to be microbiologically stable.  Stuff will grow in it unless there's enough acetic acid to stop them from growing and /or kill them.

 

Because it is not at the correct acidity, then there is no way to determine shelf life unless you do the testing yourself.

 

You are correct that heating the mixture will drive off some of the acetic acid and only make this batch worse.

 

I think you should start over and make sure that there is enough sugar in the grapes to make enough alcohol to be converted to acetic acid.  Do the initial fermentation to alcohol until the alcohol reaches the maximum.  Then keep the next fermentation running until the acidity is high enough.  You may be able to track it with pH paper, remembering that the higher the acidity, the lower the pH.  I would run the second fermentation until the pH is around 2, and then have it tested.

 

I have seen mold grow in cider vinegar in the refrigerator over a long period of time, so just refrigerating it does not guarantee that it won't grow anything.

 

Good luck,

Martha

[jonny84]

Thanks a lot for your prompt response and the useful advice !

 

I was wondering if there is any intervention for making the low acidic vinegar microbiologically stable.

For example can i add a type of commercical acid (e.g. acetic acid or tartaric acid) or a type of preservative (sulfites/metabisulfites) ?

 

Νot sure if what i suggest is feasible though. Sorry to bother again, but I am trying to find possible solutions in order to save the present batch, before deciding that i have to throw it away.

 

Kind regards

John

[Charles.C]

Dear jonny,

 

So what is the pH ?

 

Rgds / Charles.C

[jonny84]

Dear Charles

 

Thank you for the reply.

 

The lab, which i sent the samples to, only measured the vinegar's acidity which is 3.5%. I was told that this is below the safe limit (6%). I didn't get any pH measurement.

 

My mistake was that i evaluated the vinegar's acidity only based on taste and decided to remove the mother of vinegar very early. By the way the taste was so sharp that i was quite sure that my vinegar is very acidic !....I sent the sample to the lab after removing the mother of vinegar.

 

Now i am trying to come up with possible solutions in order to make the batch safe for consumption. I am thinking of doing the following steps:

 

1) Measure once again the vinegar's acidity plus pH (with lab analysis/pH strips)

 

2) If the acidity / pH is indeed below the limits, i am thinking of doing one of the following:

    (a) Start a new fermentation by adding the mother of vinegar back to the vinegar. (Not sure if i need to add extra alcohol to boost the fermentation)

    (b) Add a kind of commercial acetic acid.

    © Add a kind of wine preservative e.g. metabisulfites  

 

3) Check again acidity/pH

 

 

Of course any comment / suggestion is more than welcome :-)

 

Since I am not a professional vinegar maker, the discussions in this forum is a learning process for me. I really appreciate your willingenss to help me !

 

Regards 

John

[MWidra]

A huge consideration is if you are going to sell this or use it in something to sell, or if you are going to use it yourself.  Please include that so we can better craft our answers.

 

If you are going to sell it or add it to a comsumer item, I don't think you should try to "re-make" it by starting up the fermentation again or by adding acetic acid. It's not allowed in the US, but Greece may be different.

 

A consumer assumes  that when it says vinegar, it has been made in a certain way.  And adding something to keep it from going bad is not a good idea, because it should be a preservative because of the acid.  If you add acetic acid, it must be food grade, not a chemical grade.  It may say USP grade, don't use ACS grade.

 

The good news is that the chemistry of making vinegar is pretty simple, so problems are easy to fix.  And it's not hard to make, so it would not be hard to make again.

 

It is very easy to check the pH with paper, and you can get pH paper from many outlets.  Make sure that it is measures the lower range of the scale.  Testing the acidity by taste is not recommended, your tongue will taste it as sour long before it is acidic enough, as you found out.

 

Waiting to hear your answer.

 

Martha

Edited by MWidra, 13 February 2015 - 12:35 PM.

[jonny84]

Dear Martha 

 

You're right i forgot to mention that it is not for selling purposes....I made it for personal use and i would also like to give it away, as a gift, to friends and relatives. Nevertheless, i want to make sure that it will not cause any food poisoning to those consuming it.

 

That's the reason why i am thinking of possible solutions like the use of acetic acid etc. However, If there is no way to make it safe for consumption, i will throw it away and start from scratch, with new raw materials. 

 

Kind regards

Ioannis

[MWidra]

 

Dear Martha 

 

You're right i forgot to mention that it is not for selling purposes....I made it for personal use and i would also like to give it away, as a gift, to friends and relatives. Nevertheless, i want to make sure that it will not cause any food poisoning to those consuming it.

 

That's the reason why i am thinking of possible solutions like the use of acetic acid etc. However, If there is no way to make it safe for consumption, i will throw it away and start from scratch, with new raw materials. 

 

Kind regards

Ioannis

Ioannis, that makes this a lot easier.

 

To make sure that it is safe for consumption, you would need to increase the acidity.  If you add plain acetic acid, that would do it, but it would also change the flavor profile, and if you want to give it as a gift, then you want it to taste good too.

 

For your purposes, re-adding the mother of vinegar and letting it run until all the alcohol is converted would be fine, and would preserve the flavor.  Make sure you test the pH of the batch before you stop the fermentation, and if it does not reach between 2 and 3, I would discard it and start over.

 

Good luck, and let us know how it works out!

 

Martha

[Charles.C]

Dear jonny,

 

Your original queries were -

 

1. > Are there any possible food safety (e.g. micobiological) issues related to low acidic homemade vinegars ?

2. > Is a homemade vinegar (heated and stored refrigerated) considered microbiologically stable, regardless of its acidity percentage ?   

3. > Is there any suggestion about the infused vinegar shelf life ? Is a two-month period acceptable, from a food safety perspective ?

 

 

I have zero experience of any kind of home wine, vinegar, etc making but a little googling  suggests -

 

1. Yes - notably botulism

2. . It's a time-related query. I assume the minimum acidity is an initial target regardless. I noticed these 2 comments - 

 

f you want to store homemade vinegar at room temperature for more than a few months, you must pasteurize it. Do this by heating it to 170 degrees Fahrenheit (use a cooking thermometer to determine the temperature) and hold it at this temperature for 10 minutes. Put the pasteurized vinegar in sterilized containers with tight-fitting lids, out of direct sunlight.

 

http://recipes.howst...egar-works2.htm

 

And, from a book - 

 

 pasturize.png   29.33KB   0 downloads

 

 

3. No idea, way outside my knowledge base.

 

I enclose below a few related comments on some of the chemical aspects discussed, The most potent advice I saw  (to a non-home experimenter like myself) was to only follow "official" procedures but I appreciate that a lot of the enjoyment presumably derives from the (hopefully safe) do-it-oneself routines. Good Luck.

 

Homemade Vinegar Acidity

Do you have any information on the acidity of homemade vinegar? It is safe to use as an ingredient in home canning recipes?

ANSWER - Store-bought vinegar is standardized to at least 5% acetic acid or about pH 3 (read the label).

The acidity of homemade vinegar is variable because of variation in characteristics of the starting material. It could contain more or less acid.

To assure a safe product when pickling or canning with vinegar, the USDA Complete Guide to Home Canning recommends using vinegar of at least 5% acidity. Homemade vinegars should not be used in canning recipes.

 

http://extension.psu...vinegar-acidity

 

Bottle your vinegar and use it like you would store-bought, except for in waterbath canning. Don’t use homemade vinegar for pickling or preserving food in jars you plan to seal and store at room temp. Acidity levels in homemade vinegars will vary and a simple pH test strip might not give you a reliable reading of the pH of your vinegar. Be safe my friends. (I’d use this vinegar for pickles you make and keep only in the fridge, though.)

 

http://www.hipgirlsh...ap-vinegar.html

 

A Homemade Vinegar Caution

The acidity of homemade vinegar varies greatly. If you make your own vinegar, do not use it for canning, for preserving, or for anything that will be stored at room temperature. The vinegar's acidity, or pH level, may not be sufficient to preserve your food and could result in severe food poisoning. The pH level in homemade vinegar can weaken and allow pathogens, such as the deadly E. coli, to grow. Homemade vinegar is well suited for dressings, marinades, cooking, or pickled products that are stored in the refrigerator at all times.

 

http://recipes.howst...egar-works2.htm

 

http://forums.garden...o-kill-botulism

This is an extended forum discussion regarding the relationship of pH to safety and its measurement. Participants seem to include food technologists and home product enthusiasts.

 

Rgds / Charles.C

[jonny84]

To Marhta:

I think re-adding the mother of vinegar would be the best idea. I hope it will work out...i will let you know !

 

To Charles:

Very useful source of information! I looked through it but definetely it is worth to be read carefully ... Thanks a lot for taking the time to answer my questions !

 

Kind regards

John (or Ioannis in the Greek language )