Why is a pig-skin like substance floating on top of my vinegar?
Apologies if this is off-topic.
Every year, I make about 25 litres of cider vinegar. I wash the apples in a bucket of tap water, press them, add a sachet of yeast and leave the fermenting vessel in the garage. The juice is very acidic so not very pleasant to drink. It does however make tasty vinegar.
I have several fermenting buckets in the garage each with a different vintage of vinegar. Floating in each is a jelly-like mother of vinegar. Today I discovered that the yeast in one of the vessels (18 month vintage) has gone a bit wonky. The mother is about an inch thick. It's mostly jelly-like but the very top has the texture of pig skin, is very tough, and smells like cheese. The vinegar has lost its acidic taste and also has a hint of cheese.
Can anyone tell me what might have happened? Why has the mother become so tough? Why does it smell like cheese? Is it safe to eat?
Best Answer
That looks like a symbiotic culture of bacteria and yeast -- a SCOBY.
As to why a SCOBY developed in one vessel and not the others, only guesses can be made. I found a blog post that may offer an explanation:
So a SCOBY is typically a SCOBY for all starting vinegar and kombucha fermentations when slow processes like vat or barrel fermentation are used. Both terms can work at this point. However, for vinegar around 1% acidity the yeast die off and at higher acidities the lactic acid bacteria die off as well leaving only acetic acid bacteria to feed on alcohol. At this point it is only a mother of vinegar containing one type of organism. Kombucha acidity usually ends between 0.5-1% while vinegar is 4% minimum and usually 5%. So calling a fermenting vinegar mother a SCOBY isn’t strictly accurate.
It may be the case that the yeast grew faster than the lactic acid bacteria and the solution never reached >1% acidity in that vessel. I would be interested to know if the pH of that vessel is higher than the others.
Pictures about "Why is a pig-skin like substance floating on top of my vinegar?"
What is floating in my vinegar?
When you find a bit of stringy sediment, large or small, in a bottle of vinegar don't fret. In fact \u2014 congratulations \u2014 you have a mother. A vinegar mother, that is. Yes, it looks rather grungy and scary, floating on the top of the vinegar like that, but this spongy mass of bacteria is completely harmless.What is the black stuff floating in my apple cider vinegar?
It's a dark and cloudy (some prefer to call it slimy) substance (or sediment) that is usually found near the bottom of the bottle. The mother is a result of vinegar bacteria and occurs in vinegar naturally. It's actually cellulose and it's harmless, plus it's the most nutritious part of the vinegar.What is growing in my apple cider vinegar?
"The 'mother' in apple cider vinegar is a culture of beneficial bacteria involved in the creation and fermentation of vinegar. The mother is usually found in unrefined and unfiltered versions of apple cider vinegar, which can carry more benefits than the filtered varieties.Can bacteria grow in vinegar?
The bacteriostatic and bactericidal actions of vinegar on food-borne pathogenic bacteria including enterohemorrhagic E. coli (EHEC) O157:H7 were examined. The growth of all strains evaluated was inhibited with a 0.1% concentration of acetic acid in the vinegar.PUT APPLE CIDER VINEGAR ON YOUR FEET AND SEE WHAT HAPPENS!
More answers regarding why is a pig-skin like substance floating on top of my vinegar?
Answer 2
Different organisms grew. In the different batch, either a contamination occured, or the growth conditions were different (pH, alcohol content, sugar content etc).
Don't know if it is edible.
As an example, some of the differing bacteria and their growth preferences are mentioned in the below article, in the section Acetic Acid bacteria
The Scientific World Journal. Volume 2014 |Article ID 394671 | http://doi.org/10.1155/2014/394671
Acetic Acid Bacteria and the Production and Quality of Wine Vinegar
by: Albert Mas , María Jesús Torija, María del Carmen García-Parrilla, and Ana María Troncoso Available at: http://www.hindawi.com/journals/tswj/2014/394671/
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Viktoriya Stasik, Kammeran Gonzalez-Keola, Karolina Grabowska, Karolina Grabowska