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Vinegar is one of the most versatile ingredients in the kitchen. It comes in many styles and brands, can be made from any food which contains sugar or alcohol and has been used to make everything from fluffy pancakes to salad dressings and yes it has many roles to play in fermentation.
Vinegar can be used at the beginning stages of fermentation to lower the pH of foodstuffs to below 4.6. This protects the fermentation from contamination by unwanted microbial growth such as Clostridium botulinum. In later stages it can be used to adjust the consistency and acidity of a finished product.
These are just a few of the ways vinegar is used in fermentation. It is a very versatile product and depending on the type of fermentation it is used in different ways.
Use Vinegar to Sanitize Fermentation Equipment
Vinegar is a weak acid which has a toxic effect on acidic sensitive microorganisms. These include organisms like clostridium botulinum, escherichia coli, staphylococci, and Salmonella spp. These bacteria are inhibited in acidic conditions below a pH of 6.0, since most vinegar has a pH below 3.0 it is effective as a sanitizer for most home fermentation.
To use vinegar for sanitation you can either dip a clean cloth into a bowl of vinegar and wipe the surfaces you want sanitized or pour the vinegar directly into the container and swish it around until all the surfaces are wet from the vinegar. Pour any excess vinegar out and let air dry.
Use Vinegar to Adjust the Consistency of a Finished Fermentation
When making fermented sauces such as hot pepper sauce, salsa or chutney it is sometimes necessary to alter the consistency. To do this most normal food preparation uses water or oils of various types but when fermenting it is important to maintain the acidic conditions found in the fermentation. By adding vinegar the acidic conditions can be maintained while allowing a more fluid product.
When using vinegar to alter the consistency of a finished ferment there are a few things to avoid:
- Adding too much vinegar making it too fluid
When adding vinegar to alter the consistency be sure to add little amounts at a time. It is easy to add vinegar but once it is added it cannot be removed.
- Using vinegar with alters the flavor of the ferment
Vinegar is not a benin flavor and each type of vinegar has a specific flavor profile. When using vinegar to alter the consistency use vinegar which will not alter the flavor too much.
Don’t use balsamic vinegar to thin out a hot pepper sauce as it will add a different flavor profile to the sauce. Instead use white vinegar, hot pepper vinegar or apple cider vinegar.
When making a barbeque sauce you can adjust the consistency with any number of vinegars like white, balsamic, mead or stout/porter vinegar. These add flavors which can go well with a barbeque sauce as well as adding to the flavor profile.
Use Vinegar to Dilute Some of the Salt in Highly Salted Fermentations
Some fermentations if left alone will be very salty. Hot peppers used to make tabasco sauce are highly salted because of their long aging time (they are aged in wooden barrels for a minimum of three years). Such fermentations cannot be consumed with such a high salt content so they must be diluted with some type of acid.
Vinegar is ideal for this as it is a naturally produced weak acid which can enhance the flavors of a hot sauce or other condiment while ensuring the fermentation remains below a pH of 4.6. Add enough vinegar to dilute the concentration of the salt until you like the flavor. Let the fermentation age for a week or so for the flavors to mature.
How to Ferment fruits and vegetables using vinegar
- Use vinegar to lower the pH
A high percentage of spoilage bacteria are inhibited by acidic conditions. This includes Escherichia coli, staphylococci, and Salmonella spp. These bacteria are present in nature and are found on a wide variety of foods.
The use of vinegar at the beginning stages of fermentation prevents these bacteria from growing, preventing sickness or spoilage. Just add a little vinegar at the beginning of the fermentation to lower the pH, giving the wanted microorganisms a chance to dominate the fermentation.
- Use vinegar to add flavor
Vinegar comes in all types of flavors. Made from anything from apples to grain alcohol. Each type will produce a different flavor acid level and color so depending on the flavor you are after choose your vinegar addition with the end product in mind.
Fermentations like Hot Fermented Salsa need a sharp fresh vinegar like apple cider, pineapple or hot pepper vinegar. Other fermentations like Italian tomato sauce can be flavored with a well aged balsamic vinegar which adds additional flavors which augment the sauce nicely.
Add small amounts of vinegar to the finished fermentation and stir. Taste after each addition so as to not over do the vinegar flavor. The flavor will continue to develop once the vinegar has been added so be careful not to add too much.
- Use vinegar to clean the equipment
The low pH of vinegar can destroy the cell bodies of some unwanted spoilage and pathogenic bacteria. By using vinegar as a wiping solution to reduce the number of unwanted bacteria on the surfaces of utensils and containers the population of these uninvited guests is greatly reduced, giving the desired bacteria and yeast a chance to dominate a culture.
There are three levels of cleanliness which are usually spoken of (almost interchangeably) when it comes to fermentation.
- Clean
Can be achieved through washing with soap and water and rinsing with clean flowing water.
- Sanitized
Is achieved through heating or chemical means. This can be done through dipping equipment in a sanitizer liquid, wiping with clean cloths dipped in sanitizer or spraying.
- Strealized
This requires high heat for extended periods of time. Once the equipment has been sterilized it must be treated especially carefully because contact with unsterilized objects will contaminate it again.
For vegetable fermentation having clean equipment is enough as the unwanted bacteria will be inhibited through environmental means. This is achieved with the addition of salt, placing the vegetables in an anaerobic environment and controlling the temperature.
For some fermentations which have a long fermentation time or a delicate flavor sanitized conditions can be beneficial. Sanitizing can be achieved using vinegar due to its acidic nature. The unwanted bacteria which can cause spoilage or illness are destroyed by the acidic nature of the vinegar.
To achieve a sanitized environment wash all equipment and surfaces with soap and water. Rinse well to remove any soap residue.
Fill a new spray bottle with distilled white vinegar and spray all surfaces. Allow to air-dry. Meanwhile soak a clean cloth in vinegar and wipe all equipment and containers with it. Let air-dry.
- Use vinegar to add bacteria
Well aged vinegar has very little active acetic acid bacteria in it. This is because of the lack of food energy left in the vinegar after a long period of aging but young vinegar aged less than six months does have some active acetic acid bacteria which can multiply rapidly when provided with the right environment.
To add additional acetic acid bacteria into a vinegar fermentation use young vinegar to lower the pH at the beginning stages of fermentation. This will do two things:
- It will lower the pH
- Add some new acetic acid bacteria
- Use vinegar to adjust consistency
Some fermentations turn out thicker than intended. This often happens when a sauce is blended for usage in a bottle. If it is too thick it can be difficult to pour. By adding some vinegar you can thin the consistency of the sauce.
Add small amounts of vinegar and blend. Test regularly for the consistency you are looking for. Once you have reached the desired viscosity you can filter the sauce to remove any solids or simply pour it into a bottle and refrigerate.
Can vinegar be fermented into alcohol?
Once a liquid has turned into vinegar it cannot be converted back into alcohol. Vinegar is a byproduct of the metabolism of alcohol into acetic acid by acetic acid bacteria whereas alcohol is produced from the metabolism of simple sugars into alcohol mainly by yeasts.
This is a one way process, alcohol cannot be made out of vinegar as the food energy which yeasts use (the microorganism responsible for most alcohol production) are simple sugars.
Acetic acid on the other hand can metabolize simple sugars, alcohol as well as acetic acid for growth. This is why wine and beer producers go through great lengths to avoid exposure.
Does Vinegar Stop Fermentation?
Vinegar is considered a weak acid and can be used to inhibit the growth of spoilage bacteria in the beginning stages of fermentation. This use leads some people to believe that it will kill all microorganisms which cause fermentation.
Vinegar does not stop fermentation as the yeast and bacteria which are responsible for fermentation are acid tolerant microorganisms. These include lactic acid bacteria which have an acid tolerance of 2.0 and yeasts which can survive in a pH of 2.2. To reach such low pH values the fermentation would become inedible.
Fermentation stops through the use for temperature treatments or lack of food energy. Temperature methods can be through heat treatments such as canning or through freezing. Refrigeration will slow the fermentation but not stop it.
Lack of food energy also will stop fermentation. This happens when the sugars found in the food are all consumed by the bacteria and yeasts. This is how many aged fermentations are produced such as wine, soy sauce and balsamic vinegar.